AT&T 555-025-201 DEFINITY® Communications System Network and Data Connectivity
CONTENTS ________________________________________________________________________________________ ______________________________________________________________________________________ A AB BO OU UT TT TH HIIS SD DO OC CU UM ME EN NT T xxvviiii PREREQUISITE SKILLS AND KNOWLEDGE xvii DOCUMENT ORGANIZATION xvii HOW TO MAKE COMMENTS ABOUT THIS DOCUMENT xix 11..
iv CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MULTIPLEXING OUTSIDE THE SWITCH 1-29 Multiplexing onto T1 Trunks 1-29 Compressing the Signal 1-31 Altering Channel Assignments on T1 Trunks 1-31 Getting the Signal Ready for the Central Office 1-31 Changing the Transmission Medium from Met
CONTENTS v ________________________________________________________________________________________ ______________________________________________________________________________________ Internal Dial Plan 2-8 Auxiliary Call Information 2-10 Automatic Alternate Routing 2-11 Automatic Route Selection 2-14 NETWORK ADMINISTRATION 2-17 PRIVATE NETWORK TRUNKS 2-17 NETWORKING FEATURE PARAMETERS 2-17 33..
vi CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Automatic Route Selection ETN INTERACTIONS WITH OTHER NETWORKS 5-7 5-7 Extension Number Portability Clusters 5-8 Software-Defined Network 5-9 Release Link Trunk Networks — CAS and ACD 5-12 Distributed Communications System Clusters 5-14 Ma
CONTENTS vii ________________________________________________________________________________________ ______________________________________________________________________________________ Parallel vs.
viii CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ The Communication System as a LAN Backup PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS PUBLIC DATA NETWORKS 8-20 8-21 8-21 Packet-Switched Public Data Networks 8-21 Circuit-Switched Public Data Networks 8-22 PRIVATE DATA NETWORKS 8-26 Terres
CONTENTS ix ________________________________________________________________________________________ ______________________________________________________________________________________ USE OF GENERIC 2 AS A SYSTEM CLOCK REFERENCE B-29 USE OF GENERIC 1 AS A SYSTEM CLOCK REFERENCE B-30 C C.. T TR RU UN NK KIIN NG GT TE ER RM MS SA AN ND DC CA AP PA AB BIIL LIIT TIIE ES S C C--11 D D..
x CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ LIST OF FIGURES Figure 1-1. Analog-to-Digital Conversion 1-4 Figure 1-2. Transmission States for Voice Communication 1-8 Figure 1-3. Transmission States for Data Transmission 1-12 Figure 1-4. Time Slot 1-17 Figure 1-5.
CONTENTS xi ________________________________________________________________________________________ ______________________________________________________________________________________ Figure 6-3. Direct Link DCS Connections 6-5 Figure 6-4. Minimized Link Connections 6-6 Figure 6-5. DCIU/PI Linkage in a DCS Cluster 6-7 Figure 6-6. Short Haul Analog Signaling: System 75/G1 to System 75/G1 Via DSU 6-8 Figure 6-7. Long Haul Analog Signaling: System 75/G1 to System 75/G1 Via Modem 6-9 Figure 6-8.
xii CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Figure 8-9. Common ISN Configuration 8-18 Figure 8-10. LAN-to-LAN Connections Through the Switch 8-19 Figure 8-11. X.25/StarGROUP Connectivity 8-20 Figure 8-12. LAN/SNA Connectivity 8-20 Figure 8-13.
CONTENTS xiii ________________________________________________________________________________________ ______________________________________________________________________________________ Figure B-11. External and Internal Reference Levels B-19 Figure B-12. Nonpublic Network without Digital Switches B-20 Figure B-13. Proper Use of Backup Facilities B-21 Figure B-14. Improper Use of Backup Facilities B-22 Figure B-15. Optimal Diverse Routing B-23 Figure B-16.
xiv CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ LIST OF TABLES Table 1-1. Terminal/Port Compatibility 1-9 Table 1-2. Trunk Port Types 1-10 Table 1-3. Protocol States for Data Communication 1-14 Table 1-4. Physical-Layer Protocol vs. Character Code 1-15 Table 1-5. DMI Mode vs.
CONTENTS xv ________________________________________________________________________________________ ______________________________________________________________________________________ Table 8-8. Requirements for PBX-to-PBX Private Network Spectrum Connections 8-29 Table B-1. SCS References Switches B-10 Table D-1. Some CCITT Digital Standards D-6 Table D-2. Some CCITT Analog Standards D-7 Table D-3. Some CCITT ISDN Standards D-8 Table D-4. Some Well-Known Protocol Standards D-10 Table D-5.
xvi CONTENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
ABOUT THIS DOCUMENT ________________________________________________________________________________________ ______________________________________________________________________________________ This document explains how to arrange two or more communications systems in a network. It also tells how to use your communications system to connect one data communications device or network to another device or network.
xviii ABOUT THIS DOCUMENT _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ PART I • Chapter 2 — Communications System Networking — An Overview— Introduces the networking software packages that are used to implement a PBX network.
ABOUT THIS DOCUMENT xix ________________________________________________________________________________________ ______________________________________________________________________________________ HOW TO MAKE COMMENTS ABOUT THIS DOCUMENT Reader comment cards are in the back of this document. While we have tried to make this document fit your needs, we are interested in your suggestions for improving it and urge you to fill one out.
xx ABOUT THIS DOCUMENT _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
1. INTRODUCTION TO CONNECTIVITY ________________________________________________________________________________________ ______________________________________________________________________________________ This book explains two aspects of communicating through a business communications system: • Part I, Communications System Networking, explains how to arrange two or more communications systems in a network so that they communicate with each other efficiently and cost effectively.
1-2 INTRODUCTION TO CONNECTIVITY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
TRANSMISSION TYPES ________________________________________________________________________________________ ______________________________________________________________________________________ Both analog and digital transmission can be used to carry information across telephone lines and data links. ANALOG TRANSMISSION Analog transmission carries information as continuously varying electrical waves. Variables like the wave amplitude, phase, and frequency impart the information contained in the signal.
1-4 TRANSMISSION TYPES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ 1. Original signal 2. PAM pulses 6.2 5.9 4.1 3.0 2.8 1.4 1.3 Ts 6 6 3. PCM pulses 4 3 3 1 1 011 001 110 001 011 110 4.
TRANSMISSION TYPES 1-5 ________________________________________________________________________________________ ______________________________________________________________________________________ • Voice: To carry voice over digital transmission facilities, analog voice signals must be converted into digital information. To do this, the voice signal is sampled 8000 times a second. The sample is encoded according to a process called pulse-code modulation or PCM.
1-6 TRANSMISSION TYPES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ signals became feasible through the economic, operational, and reliability features of solid-state electronics.
TRANSMISSION STATES ________________________________________________________________________________________ ______________________________________________________________________________________ When you plan a communications network, there are certain rules that you cannot violate: • Analog signals cannot be carried over digital facilities without first being converted to digital. • Digital signals cannot be carried over analog facilities without first being converted to analog.
1-8 TRANSMISSION STATES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DIGITAL SWITCH 142536 7*809# DIGITAL PCM VOICE TERMINAL 142536 7*809# DIGITAL PCM VOICE TERMINAL 142536 7*809# DIGITAL PCM VOICE TERMINAL D I G I T A L L I N E A N A L O G PCM P O R T T R U N K P O R T ANALOG VOICE ANALOG
TRANSMISSION STATES 1-9 ________________________________________________________________________________________ ______________________________________________________________________________________ • Incoming digital-trunk calls to a digital switch need no conversion since the call is already PCM encoded. Incoming digital-trunk calls to analog switches are converted outside the switch at a D4 channel bank. In these cases, the digital trunk terminates at the D4 channel bank.
1-10 TRANSMISSION STATES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 1-2.
TRANSMISSION STATES 1-11 ________________________________________________________________________________________ ______________________________________________________________________________________ DATA TRANSMISSION Because of the variety of protocols that can be used in data communication, data transmission has many more options than voice.
1-12 TRANSMISSION STATES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ ORIGINATING DCE DTE DATA MODULE DTE DATA MODULE 1 RS-232 2 ASCII SWITCH DCP DESTINATION DCE D I G I T A L P O R T D I G I T A L P O R T D I G I T A L P O R T D I G I T A L P O R T RAW BITS DATA MODULE DATA MODULE D
TRANSMISSION STATES 1-13 ________________________________________________________________________________________ ______________________________________________________________________________________ Protocols Used The following is a list of the protocols that are meaningful when you transmit data to and through the switch. The list is organized by protocol layers. As you read through the list, follow the protocol changes through the transmission paths shown in figure 1-3.
1-14 TRANSMISSION STATES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ types of trunk protocols (for example, primary rate interface [PRI] and 24th-channel signaling) use DS1 protocol at layer 1. (See the Trunking section of this chapter for an explanation of these trunk types.
TRANSMISSION STATES 1-15 ________________________________________________________________________________________ ______________________________________________________________________________________ Note that both the physical-layer protocol and the DMI mode used in the connection are dependent upon the type of 8-bit code used at layer 2 between the DTE and DCE. (See tables 1-4 and 1-5.) Table 1-4. Physical-Layer Protocol vs.
1-16 TRANSMISSION STATES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DCP-line port. The only caveat is that the destination data module must be set for mode-2 DMI communication. (See appendix D for a discussion of DMI modes.
MULTIPLEXED COMMUNICATION ________________________________________________________________________________________ ______________________________________________________________________________________ As signals are transmitted away from the switch and onto a public or private network, multiplexed communication becomes an option. Multiplexed communication results from the interleaving of signals from multiple circuits into a single communications path.
1-18 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Time-division multiplexing can be bit interleaved or byte interleaved. With bit interleaving, the time slot assigned to a particular channel is one bit long and the channel recurs every 15.5 microseconds over a DS1 link.
MULTIPLEXED COMMUNICATION 1-19 ________________________________________________________________________________________ ______________________________________________________________________________________ Line Coding Line coding is the pattern that data assumes as it is propagated over a communications channel. Governing line coding is a set of parameters that must be defined for all digital transmissions.
1-20 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ ever be all zeros. Mode-2 communication always ensures signal inversion, while mode 3 usually does. ZCS is the only line coding allowed over DS1 restricted channels.
MULTIPLEXED COMMUNICATION 1-21 ________________________________________________________________________________________ ______________________________________________________________________________________ Signal Inversion Signal inversion is the replacement of all 1s in a digital transmission stream with 0s; and the replacement of all 0s with 1s. The use of signal inversion is related to the transmission facilities, the DMI mode, and the line coding.
1-22 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 1-7.
MULTIPLEXED COMMUNICATION 1-23 ________________________________________________________________________________________ ______________________________________________________________________________________ TABLE 1-7: Data-Module Capabilities (Part 2 of 2) ______________________________________________________________________________________________________ Data DMI User Data Sync Async Bit Protocol Handshake Comments Module Mode Rate Invert Packaging _______________
1-24 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ 1 SUPERFRAME = 12 FRAMES 1.5 MS, 2316 BITS FT 1 0 FS 1 0 COMBINED F 1 FRAME # 0 F1 0 0 0 F2 0 F3 1 1 1 F4 1 F5 0 1 0 F6 1 F7 F8 1 1 1 1 F9 0 0 0 F10 F11 1 F12 1 FRAME 125 µSEC.
MULTIPLEXED COMMUNICATION 1-25 ________________________________________________________________________________________ ______________________________________________________________________________________ The framing format does not place any requirement on the type of signaling or line coding to be used. However, the type of framing used at both ends of the DS1 transmission facility must be identical.
1-26 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ FRAME NUMBER FRAME BIT FRAME BIT DEFINITIONS CHANNEL 1 1 DATA LINK F BIT (DL) 8-BITS 2 CRC-6 F BIT 8-BITS 3 DATA LINK SIGNAL 8-BITS 4 FRAME SYNC PATTERN 5 DATA LINK SIGNAL 8-BITS 6 CRC-6 F BIT 7-BITS 7 DATA
MULTIPLEXED COMMUNICATION 1-27 ________________________________________________________________________________________ ______________________________________________________________________________________ Facilities using RBS carry digital data at 56 kbps. They can be used to carry voice, voice-grade data, or data that uses only 56 kbps of the available 64-kbps bandwidth (for example, mode-1 data).
1-28 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ number and the signaling state for that channel. The channel identification number is necessary since the channel signaling information may not be synchronized with the voice or data channel that it describes.
MULTIPLEXED COMMUNICATION 1-29 ________________________________________________________________________________________ ______________________________________________________________________________________ MULTIPLEXING OUTSIDE THE SWITCH As signals propagate away from the switch, they can be multiplexed onto increasingly higher-capacity facilities. As the capacity of facilities increases, the transmission medium can also change — for example, from metallic to fiber to microwave and back again.
1-30 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ HOST T1 DIGITAL PBX T1 T1 CEM T1 T1 CDM CSU CSU CSU T1 PRIVATE T1 FACILITIES T1 DACS #4ESS T1 T1 CSU #5ESS T1 CSU T1 CHANNEL BANK CDM CEM ANALOG PBX DIGITAL PBX HOST T1 DMI HOST Legend: CDM = channel di
MULTIPLEXED COMMUNICATION 1-31 ________________________________________________________________________________________ ______________________________________________________________________________________ Compressing the Signal Through a process called adaptive differential pulse-code modulation (ADPCM), voice transmissions can be compressed so that they consume only half of their original bandwidth.
1-32 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ AT&T offers two types of CSUs. The ESF T1 CSU, AT&T’s most recent offering, can be set for D4 or ESF framing, and ZCS or B8ZS line coding.
MULTIPLEXED COMMUNICATION 1-33 ________________________________________________________________________________________ ______________________________________________________________________________________ AT&T Microwave Modem 3B Computers T1 ATT CDM AT&T FAX 3510D 128 terminals at various rates 7000 Series Terminals PC 6300 System 75/85 or G1/G2 ATT Terminals 740 TMUX PC 6300 PC 6300 T1 Teleconferencing D4/CEM DIMENSION PBX 0 - 56K ATT terminals DSU T1/DS1 could be twisted pair or fiber
1-34 MULTIPLEXED COMMUNICATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Note that the Digital Access and Cross-Connect System (DACS) takes input multiplexed up to the DS1 level.
TRUNKING ________________________________________________________________________________________ ______________________________________________________________________________________ Trunks are the transmission medium through which voice and data signals travel from one switch to another. Studying the variety of ways trunks can differ can help simplify your decisions when you implement and administer a network.
1-36 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ attendant or ACD agents. • 800-service trunks — 1-way incoming trunks connecting the switch to a CO equipped to handle 800 Service calls (also known as INWATS).
TRUNKING 1-37 ________________________________________________________________________________________ ______________________________________________________________________________________ numbers (without their accompanying location code) are sent over access trunks to identify a call destination. • Bypass access trunks — 1-way outgoing trunks that connect a tandem switch to a main switch that is "homed on" another tandem.
1-38 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ the switch of origin for routing and processing, and, then, disengages the RLT, readying it for another call.
TRUNKING 1-39 ________________________________________________________________________________________ ______________________________________________________________________________________ Access can also be switched or nonswitched. • With switched access, either the LEC or interexchange carrier provides access to their switching complex for the special services for which you have contracted.
1-40 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ signals on-hook on all calls by opening the path between the tip and the ring. • LS (loop start) supervision — A supervisory signaling scheme used between a telephone and a PBX in which the telephone completes the loop current path.
TRUNKING 1-41 ________________________________________________________________________________________ ______________________________________________________________________________________ DMI — A DS1 link that uses the digital multiplexed interface (DMI) as the level 2 protocol on the bearer or information channels. AVD — When a trunk is administered as AVD, it can carry only voice and digital data. Without explicitly administering the trunk as AVD, only voice and voice-grade data are allowed.
1-42 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • Framing — On System 85 and G2, you can administer a DS1 port for either D4 or ESF framing through PROC 260 Word 1, field 6. On System 75 and G1, use the DS1 Circuit Pack Screen to set these options.
TRUNKING 1-43 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 1-10.
1-44 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
TRUNKING 1-45 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 1-11.
1-46 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
TRUNKING 1-47 ________________________________________________________________________________________ ______________________________________________________________________________________
1-48 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 1-12.
TRUNKING 1-49 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 1-13.
1-50 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
TRUNKING 1-51 ________________________________________________________________________________________ ______________________________________________________________________________________
1-52 TRUNKING _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
2. COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW ________________________________________________________________________________________ ______________________________________________________________________________________ A network is an interconnected group of communications systems that can exchange voice and data across the transmission media that connect them. Arranging communications systems into networks involves physically linking the systems (nodes) together with the appropriate hardware.
2-2 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ TYPES OF NETWORKS The type of network you install depends upon the geographical distribution of the network nodes, the capabilities you need in each node, and the relative cost of each networking alternative.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-3 ________________________________________________________________________________________ ______________________________________________________________________________________ MAIN LOCATION A TANDEM A ETN SDN LOCATION B TANDEM B MAIN MAIN SATELLITE • Electronic tandem network/Software-Defined Network (ETN/SDN) hybrid network — A network in which users served by the public network are integrated into a private ETN.
2-4 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ The networking software has been packaged to accommodate this type of network evolution. Table 2-1 shows the types of software (and their PECs) that must be activated to enable particular types of networks.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-5 ________________________________________________________________________________________ ______________________________________________________________________________________ network calls. In addition, ARS provides toll-sensitive routing. (See Network Call Processing later in this chapter for further details.) • Trunk access through dial access codes.
2-6 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ switch for processing.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-7 ________________________________________________________________________________________ ______________________________________________________________________________________ • The Uniform Dial Plan function — With this function, the switch uses the extension number to find the RNX. The RNX is used to route the call through AAR to its destination.
2-8 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ On all switches, the internal dial plan comes with the basic software.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-9 ________________________________________________________________________________________ ______________________________________________________________________________________ 9 + (NPA) + NNX + XXXX OR NETWORK OR NETWORK TO ARS DAC + EXT EXTENSION NO. STEERING EXT • DAC + EXT EXTENSION NO.
2-10 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ the extension and RNX number to AAR for processing. The UDP function is available on the System 75 and Generic 1 communications systems when either the UDP or PNA package is activated.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-11 ________________________________________________________________________________________ ______________________________________________________________________________________ • Bearer capabilities — Bearer capability (System 75 R1V3 and Generic 1 communication systems) and bearer capability classes of service (System 85 R2V4 and Generic 2 communications system) are assigned to indicate whether calls are analog or digital.
2-12 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ EXTENSION NUMBER PORTABILITY FROM INTERNAL DIAL PLAN MATCH EXT EXT + NODE + RNX TO RNX EXT + NODE CONDITIONAL ROUTING COUNT OBTAIN PATTERN UNIFORM DIAL PLAN FUNCTION MATCH RNX TO NODE EXT + RNX EXT + (N
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-13 ________________________________________________________________________________________ ______________________________________________________________________________________ Selecting a Trunk Group Various criteria make one trunk group more appropriate than another for routing a call. Among these criteria are cost, speed, transmission medium, and the bearer capability class of the call (which lets the system match like digital formats).
2-14 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Automatic Route Selection Automatic Route Selection (ARS) is the feature that handles outgoing public network calls that callers have dialed using the ARS feature access code (usually a 9).
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-15 ________________________________________________________________________________________ ______________________________________________________________________________________ TO AAR RNXs FROM INTERNAL DIAL PLAN 01X IN 1ST 3 POSITIONS MATCH WITH 10-TO-7 DIGIT CONVERSION AND UNAUTHORIZED CALL TABLE 9 + (NPA) + (NNX) + EXT 0 YES (S75/G1) YES (S85/G2) NO PARTITION GROUP NUMBER (S75/G2) 6-DIGIT TABLE IN POSITION 1 ? YES 0 OR 1 IN POSITION 2 ? FOREI
2-16 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • 0 in position 1 — ARS knows that these are IXC (Generic 1 only) or telephone company operatorassisted calls and sends them on to pattern selection.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-17 ________________________________________________________________________________________ ______________________________________________________________________________________ • When an IXC facility is chosen and the caller dialed an AT&T number. In this case, ARS can be used to insert an IXC prefix. • When an AT&T facility is chosen and the caller dialed an IXC number. In this case, ARS can be used to delete the IXC prefix. (Generic 1 only.
2-18 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 2-2.
COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW 2-19 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 2-3.
2-20 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
3. TANDEM TIE TRUNK NETWORKS ________________________________________________________________________________________ ______________________________________________________________________________________ A tandem tie trunk (TTT) network is an network of DIMENSION, System 85, and/or Generic 2 switches linked by dial-repeating trunks. In this type of network, calls are not automatically routed to the final destination.
3-2 TANDEM TIE TRUNK NETWORKS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
4. MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES ________________________________________________________________________________________ ______________________________________________________________________________________ Main-satellite/tributary (MS/T) networks are arrangements of switches in which one switch is designated as the main, while subtending switches are satellites or tributaries.
4-2 MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MS/T CONFIGURATIONS There are two types of MS/T configurations: main-satellite and main-tributary.
MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES 4-3 ________________________________________________________________________________________ ______________________________________________________________________________________ ETN NETWORK CENTRAL OFFICE LDN (727-XXXX) TRIBUTARY EXTENSIONS 3600-3699 NETWORK INWARD DIALING (NID) RNX (542-XXXX) TIE TRUNK CENTRAL OFFICE LDN/DID (725-XXXX) MAIN PBX EXTENSIONS 2800-2899 3200-3299 REMOTE ACCESS TIE TRUNK SATELLITE PBX
4-4 MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MS/T FEATURES MS/T configurations are implemented differently on different communications systems: • The System 75 and Generic 1 communications systems use the Uniform Dial
MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES 4-5 ________________________________________________________________________________________ ______________________________________________________________________________________ S/T: DIMENSION, SYSTEM 85, GENERIC 2 S/T: DIMENSION, SYSTEM 85, GENERIC 2 S/T: SYSTEM 75, GENERIC 1 S/T NETWORKING PACKAGE: MULTIPREMISES WITH ETA ST NETWORKING PACKAGE: MULTIPREMISES WITHOUT ETA S/T NETWORKING PACKAGE: UDP MAIN MAIN S/T S
4-6 MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MAIN: DIMENSION, SYSTEM 85, GENERIC 2 MAIN: ALL SWITCHES MAIN AND S/T: SYSTEM 75 OR GENERIC 1 MAIN NETWORKING PACKAGE: MULTIPREMISES MAIN NETWORKING PACKAGE: PNA, ETN M
MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES 4-7 ________________________________________________________________________________________ ______________________________________________________________________________________ Routing Incoming Calls Except for a configuration that incorporates a bypass access trunk between an ETN node and a tributary, all calls into the MS/T complex come through the main. Calls arrive at the main from both the public and private network.
4-8 MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ From the main to the satellite or tributary: • The caller dials the destination extension and the AAR databases route the call appropriately.
MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES 4-9 ________________________________________________________________________________________ ______________________________________________________________________________________ • • • • Senderized operation. Can automatically delete digit(s) at the sending end and add digit(s) at the receiving end. Can be either touch-tone or rotary operation.
4-10 MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Distributed communication system (DCS) software can coexist with MS/T software. Therefore, it is possible for MS/T network switches to be nodes in a DCS cluster.
5. ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES ________________________________________________________________________________________ ______________________________________________________________________________________ An ETN is a wide-area private network that tandems calls through one or more switches to reach their destinations. In an ETN, the tandem switches are tied together with tie trunks and other equipment needed to transmit voice and data.
5-2 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ The characteristics of a hierarchical network (see figure 5-1) are: • • • • Each tandem switch has an assigned level (upper and lower).
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-3 ________________________________________________________________________________________ ______________________________________________________________________________________ SATELLITE MAIN MAIN UPPER LEVEL DIMENSION PBX TANDEM SWITCH DDD WATS FX IXC TRIBUTARY FINAL OVERFLOW SYSTEM 85 TANDEM SWITCH FINAL FINAL BYPASS ACCESS TIE TRUNK INTERMEDIATE HIGH USAGE INTERMACHINE TIE TRUNKS OVERFLOW PRIMARY HIGH USAGE SYSTEM 85 TANDE
5-4 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Access and Bypass Access Tie Trunks An access tie trunk is a 1-way outgoing or 2-way trunk connecting a main to a tandem switch.
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-5 ________________________________________________________________________________________ ______________________________________________________________________________________ Off-Net Trunks The public network trunks carry off-net AAR call traffic when the call is identified by a 10-digit number (NPA-NXX-XXXX). In some cases, calls may be carried as far as possible on-net and then routed to offnet trunks.
5-6 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ TO C.0. TANDEM PBX ATTENDANT (555) 555-0111 555-1234 TO C.0. TANDEM PBX 444-1234 ATTENDANT (444) 666-0111 TANDEM PBX TO C.0. (666) ATTENDANT 444-0111 666-1234 TO C.0. TO C.0.
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-7 ________________________________________________________________________________________ ______________________________________________________________________________________ Note that a System 75 or Generic 1 communications system that functions as a tandem supports only a 7digit uniform numbering plan; while DIMENSION, System 85, and Generic 2 communications systems support a 5-, 6-, or 7-digit uniform numbering plan.
5-8 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ In some cases, the software and/or administration used to implement the above types of networks reside on the same switch as do the ETN (Standard Network) package or the Private Network Acces
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-9 ________________________________________________________________________________________ ______________________________________________________________________________________ Like System 85 and Generic 2 communications systems that function as ETN tandems, ENP nodes require the ETN (Standard Network) package.
5-10 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ SWITCHED ACCESS EQUAL DID (4 OR 5 DIGIT) ACCESS S75/ END OFFICE LEC G1 AT&T SDN NPA-NXX-XXX NCP 7- OR 10DIGIT ETN ETN PNI S85/ G2 PNI ACP DIM FP8 ACP SO SO 0- TO 7DIGIT S85/ G2
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-11 ________________________________________________________________________________________ ______________________________________________________________________________________ AT&T SDN NCP (3) DATA BASE QUERY ETN PNI ACP SO (6) 592-3456 ACP (5) ROUTE CALL (4) BILLING & ROUTING INSTRUCTIONS (2) 592-3456 SO 3456 592 SDN DIRECT ACCESS (1) 8-592-3456 Figure 5-6. Call Flow SDN - to - ETN 4.
5-12 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ AT&T SDN (4) DATA BASE QUERY ETN NCP (5) BILLING & ROUTING INSTRUCTIONS (3) 346-1234 PNI ACP (2) 346-1234 SO ACP (6) ROUTE CALL (7) 1234 SO SDN DIRECT ACCESS (1) 8-346-1234 1234 3
ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-13 ________________________________________________________________________________________ ______________________________________________________________________________________ TANDEM AAR CAS BRANCH LDN G1/G2 TIE LINE RLT AAR CAS MAIN RNX 333 TIE LINE AAR AAR TIE LINE CONSOLES RLT TIE LINE CAS BRANCH LDN INTELLIGENT MAIN D2000 FP8 RLT SYS.
5-14 ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Distributed Communications System Clusters The distributed communications system (DCS) is a information system that provides a messaging overlay for main-satellite/tributary (MS/T) networks,
6. DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) ________________________________________________________________________________________ ______________________________________________________________________________________ The distributed communications system (DCS) is a information system that provides a messaging overlay for main-satellite/tributary (MS/T) networks, electronic tandem networks (ETNs), or ETN-MS/T complexes that are designed for DCS implementations.
6-2 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DCS CLUSTERS DCS is installed on groups of switches, called "DCS clusters." Nodes in DCS clusters can be DIMENSION, System 75, System 85, Generic 1, or Generic 2 communications system.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-3 ________________________________________________________________________________________ ______________________________________________________________________________________ Tie Trunks In ETNs, the tie trunks connecting DCS nodes are intermachine tie trunks. On the System 75 and Generic 1 communications system, they are administered as tandem trunks; while on the DIMENSION, System 85, and Generic 2 communications system, they are type 41 trunks.
6-4 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ administrable amount of time elapses, the packet is retransmitted. The link can be reset and restarted if packets are not delivered or if the packets arrive out of sequence.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-5 ________________________________________________________________________________________ ______________________________________________________________________________________ (See chapter 9 for detailed permanent connection configurations. The DEFINITY Communications System System 75 and Generic 1.
6-6 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Linkage Design Signaling links between DCS nodes can be designed with an underlying direct linkage or minimized linkage philosophy. Direct Linkage.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-7 ________________________________________________________________________________________ ______________________________________________________________________________________ A 1 4 2 3 1 1 1 3 C 4 3 D 4 B 1 2 2 4 E 3 2 4 3 2 2 2 1 1 2 1 G 1 H 4 3 3 4 I 2 F 3 3 4 4 1 3 2 K 4 2 1 1 3 4 2 J L 4 3 Figure 6-5. DCIU/PI Linkage in a DCS Cluster Mixed Link Connections.
6-8 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DCS SIGNALING LINK CONNECTIONS Many variables influence how the signaling channel on one DCS node is connected to the signaling channel on another DCS node.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-9 ________________________________________________________________________________________ ______________________________________________________________________________________ PI PI SIGNALING CHANNEL TN764 (DIGITAL LINE) TN760 (TIE TRUNK) TN722 OR TN767 (DS1) DCP MTDM RS232 MODEM RS232 MODEM MTDM DCP ANALOG OR DS1 VOICE CHANNEL SYSTEM 75/G1 TN764 (DIGITAL LINE) TN760 (TIE TRUNK) TN722 OR TN767 (DS1) SYSTEM 75/G1 Figure 6-7.
6-10 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ PI PI SIGNALING CHANNEL TN764 (DIGITAL LINE) DCP MTDM MPDM TN764 (DIGITAL LINE) DCP RS232C MALE/MALE CABLE TN760 (TIE TRUNK) TN722 OR TN767 (DS1) TN760 (TIE TRUNK) TN722 OR TN767 (DS1) ANALOG OR DS1 VOICE
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-11 ________________________________________________________________________________________ ______________________________________________________________________________________ SIGNALING CHANNEL RS449 DCIU DCIU RS232C MODEM RS232C RS449 MODEM DCIU DCIU RS449 TO RS232C CONVERSION OR TN760 (TIE TRUNK) TN722 OR TN767 (DS1) OR SN232 (TIE TRUNK) ANN11 (DS1) GENERIC 2 WITH UNIVERSAL MODULE TN760 (TIE TRUNK) TN722 OR TN767 (DS1) SN233 (TIE TRUNK) ANN11 (DS1
6-12 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ System 75 or Generic 1 (G1) to System 85 or Generic 2 (G2) SIGNALING CHANNEL PI TN754 (DIGITAL LINE) RS449 DCIU DCIU RS232C DCP DSU DSU MTDM RS232C TO RS449 CONVERSION TN760 (TIE TRUNK) TN722 OR TN767 (DS
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-13 ________________________________________________________________________________________ ______________________________________________________________________________________ PI RS232C TO RS449 CONVERSION DCIU MPDM DCIU RS449 SN270B (DIGITAL LINE) OR TN754 (DIGITAL LINE) T1 USING AVD DS1* CARRIER TN722 OR TN767 (DS1) TN722 OR TN767 (DS1) ANN11 (DS1) SYSTEM 85/G2 WITH TRADITIONAL MODULE SYSTEM 75/G1 GENERIC 2 WITH UNIVERSAL MODULE *ONE OF THE 23 AVD
6-14 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ SIGNALING CHANNEL PI TN754 (DIGITAL LINE) DCIU DCIU RS449 DCP MPDM OR TN760 (TIE TRUNK) TN722 OR TN767 (DS1) SN233 (TIE TRUNK) ANN11 (DS1) ANALOG OR DS1 VOICE CHANNEL SYSTEM 75/G1 SYSTEM 85/G2 WITH TRADITI
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-15 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 6-3.
6-16 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Group Selection button. Busy Verification of Terminal Lines The attendant can verify a terminal’s state (busy or idle) at any DCS node/endpoint.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-17 ________________________________________________________________________________________ ______________________________________________________________________________________ Transparent Voice Terminal Features The following voice terminal features operate transparently at voice terminals attached to nodes within a DCS cluster. (See table 6-4 for a list of transparent voice terminal features and the communications systems from which you can expect transparency.
6-18 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • If the called party is at a System 85, Generic 2, or DIMENSION PBX node, the callback call can only be activated if the called node is returning busy tone or special audible ringback.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-19 ________________________________________________________________________________________ ______________________________________________________________________________________ feature allows the caller to leave a ‘‘call me’’ message for the called party. The switch automatically creates a message that contains: calling party name and extension number, date, time, and a short customer-specified message such as ‘‘please call’’.
6-20 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ SYSTEM 85 (R2V2-V4), SYSTEM 75 (R1V3), GENERIC 1, AUDIX "HOST" GENERIC 2, OR SWITCH DIMENSION PBX FP8 ISSUE 3L8 VOICE LINKS SWITCH ACD TIE GROUP TRUNKS DATA LINKS COMMUNICATIONS DCIU PROCESSOR DCS SIGN
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-21 ________________________________________________________________________________________ ______________________________________________________________________________________ • Leave Word Calling — Leave Word Calling messages can be stored on AUDIX for users on remote switches. Leave Word Calling activation can be from any switch.
6-22 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ A DCIU or PI Call goes over this tie trunk. C All links and channels between here used up , let’s say, so take detour via B to find a route to C.
DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-23 ________________________________________________________________________________________ ______________________________________________________________________________________ ADMINISTRATION CONSIDERATIONS To determine how to administer DCS nodes, refer to the DEFINITY Communications System System 75 and Generic 1.
6-24 DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • If the far-end switch from a System 75 or Generic 1 is a System 85, Generic 2, or DIMENSION PBX and if a 5-digit dialing plan is used with AAR that routes the first two digits to an RNX, intermachine tie trunks mu
7. DATA CONNECTIVITY — AN OVERVIEW ________________________________________________________________________________________ ______________________________________________________________________________________ This part of the AT&T Network and Data Connectivity document explains how to use your communications system to connect one data communications device or network to another device or network.
7-2 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DATA COMMUNICATIONS VARIABLES Data terminal equipment (DTE) are devices where data originates and/or terminates. Host computer ports and terminal ports usually function as DTEs.
DATA CONNECTIVITY — AN OVERVIEW 7-3 ________________________________________________________________________________________ ______________________________________________________________________________________ NETWORKING DIGITAL PBX PUBLICSWITCHED NETWORK PACKET SWITCH ISN OR STARLAN ASYNCHRONOUS AND SYNCHRONOUS POOLED MODEM SYNCHRONOUS 3270 DATA MODULE DIGITAL PBX CLUSTER CONTROLLER 3270-TYPE TERMINAL 3270 DATA MODULE ASYNCHRONOUS PERSONAL COMPUTER MAINFRAME COMPUTER DIGITAL PHONE AT&T 6500
7-4 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ communications path. • Interface protocols that control communication between links in a data network, but do not cross the network.
DATA CONNECTIVITY — AN OVERVIEW 7-5 ________________________________________________________________________________________ ______________________________________________________________________________________ ASYNCHRONOUS (START/STOP) TRANSMISSION ONE CHARACTER (7 OR 8 BITS) AT A TIME IDLE ST 1 2 3 4 5 6 7 P SP ST 1 2 ••• ST = START, P = PARITY, SP = STOP SYNCHRONOUS TRANSMISSION SYN SYN SOH TEXT ETX BCC BLOCK OF CHARACTERS Figure 7-2. Synchronous vs.
7-6 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MODES OF OPERATION RECEIVE SEND SIMPLEX HALF DUPLEX (TURNAROUND) •• FULL DUPLEX Figure 7-3. Modes of Link Operation Parallel vs.
DATA CONNECTIVITY — AN OVERVIEW 7-7 ________________________________________________________________________________________ ______________________________________________________________________________________ 1 0 1 1 0 1 SERIAL 0 0 1 0 1 1 0 1 0 0 PARALLEL 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 Figure 7-4. Serial vs.
7-8 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Channel Assignment — Dial-up vs. Dedicated Connections The assignment of a communications stream to a path or channel through a circuit switch is made dynamically or on a permanent basis.
DATA CONNECTIVITY — AN OVERVIEW 7-9 ________________________________________________________________________________________ ______________________________________________________________________________________ At the point in the communications stream where the transmission mode changes between analog and digital the switch automatically inserts a modem pool member.
7-10 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 7-1.
DATA CONNECTIVITY — AN OVERVIEW 7-11 ________________________________________________________________________________________ ______________________________________________________________________________________ Note that BRI terminals follow the asynchronous user interface specification, which means that the terminals are always in the command mode by default. This implies that whenever a call is to be placed, the user must always dial "d" at the very least.
7-12 DATA CONNECTIVITY — AN OVERVIEW _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DCP "UP TO 21 SYNCHRONOUS CHANNELS" RS-232C MTDM DCP SYSTEM 85, SYSTEM 75, OR GENERIC 1/2 • • • MTDM DCP • • • • RS-232C M U X DDS NETWORK FACILITIES DSU RS-232C MTDM DSU M U X • • • • 3002 TYPE PRIVATE LINE
8.
8-2 DATA COMMUNICATIONS CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
DTE CONNECTIONS ________________________________________________________________________________________ ______________________________________________________________________________________ Through your communications system, you can communicate with both asynchronous and synchronous DTEs. The DTEs may include terminals and personal computers, as well as host computer ports. Designing these connections is a multi-step process: • First, you must determine whether the DTEs are compatible.
8-4 DTE CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Terminal Emulators Many host and personal computer manufacturers endorse terminal emulation software that will send data in a format that the destination DTE expects.
DTE CONNECTIONS 8-5 ________________________________________________________________________________________ ______________________________________________________________________________________ DCE POSSIBILITIES DCEs that communicate with AT&T communications systems can be categoried as follows: • Data Modules — Link DTEs with the switch’s digital ports — that is, BRI and DCP ports.
8-6 DTE CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Standalone Data Modules Standalone data modules are self-contained pieces of equipment that transform the transmission signal as it enters and exits the switch.
DTE CONNECTIONS 8-7 ________________________________________________________________________________________ ______________________________________________________________________________________ If you choose to use DCP (digital-line or GPP) ports for the connection, refer to table 8-1 to determine which DCE best meets your needs. Table 8-2 lists your choices if you select a BRI port for the connection.
8-8 DTE CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 8-1.
DTE CONNECTIONS 8-9 ________________________________________________________________________________________ ______________________________________________________________________________________ TABLE 8-1.
8-10 DTE CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MODEM POOLING CONNECTIONS Modem pooling connections are used under the following conditions: • When an off-premises connection is made over analog facilities, while on-premises facilities are digital.
DTE CONNECTIONS 8-11 ________________________________________________________________________________________ ______________________________________________________________________________________ TN754 OR SN270 DCP 7400A RS-232D PBX TN742 OR SN243 TIP-RING MODEM (HAYES AT COMPATIBLE) Figure 8-3. External Modem Pool Using Intelligent Modems (Hayes-compatible) EIA SYSTEM 75, GENERIC 1 7400B, ADU, ETC ANALOG DIGITAL PORTION ANALOG PORTION DM MODEM POOLED MODEM CARD (TN758) Figure 8-4.
8-12 DTE CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DTE DATA MODULE 7400A S75/S85 24th D G1/G2 CHANNEL D A MODEM PRIVATE DATA NETWORK S75/S85 24th G1/G2 D CHANNEL A D MODEM D = DCP Port; A = Analog Port Figure 8-5.
LOCAL AREA NETWORK CONNECTIONS ________________________________________________________________________________________ ______________________________________________________________________________________ A local area network (LAN) is a collection of geographically close PCs, printers, and hosts that communicate with each other over a high-speed link.
8-14 LOCAL AREA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ LAN TRANSMISSION MEDIA The transmission media through which LAN nodes are linked may be fiber optic cable, coaxial cable, twisted-pair, or a combination of these.
LOCAL AREA NETWORK CONNECTIONS 8-15 ________________________________________________________________________________________ ______________________________________________________________________________________ — It can give outside users access to the LAN and the hardware and software resources that reside there. — It can provide LAN users with access to the lines and trunks attached to communications system. • Second, it can let LAN nodes communicate with nodes in other networks.
8-16 LOCAL AREA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Operating Type of Gateway PC __________________________________________________________ LAN System Software __________________________________________________________ StarLAN, StarGROUP LAN Manag
LOCAL AREA NETWORK CONNECTIONS 8-17 ________________________________________________________________________________________ ______________________________________________________________________________________ REMOTE PC (RPC) CLIENT S75/85/G1/G2 LAN MANAGER REMOTE GATEWAY 7400B 7400A/ ADU/ MADU REMOTE PC (RPC) CLIENT (OFF PREMISES) 6386 PC LAN WITH StarGROUP MODEM POOL MODEM Figure 8-7.
8-18 LOCAL AREA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ ISN Communication The AT&T Information System Network (ISN) is a packet-switched LAN that links its nodes together through a data-only digital switch.
LOCAL AREA NETWORK CONNECTIONS 8-19 ________________________________________________________________________________________ ______________________________________________________________________________________ S75/S85/G1/G2 LAN BRIDGE OR ROUTER MPDM D C P D S 1 S75/S85/G1/G2 T1 D S 1 D C P MPDM BRIDGE OR ROUTER LAN Figure 8-10. LAN-to-LAN Connections Through the Switch Table 8-5.
8-20 LOCAL AREA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ S75/85/G1/G2 S75/85/G1/G2 T-1 LAN WITH StarGROUP 3B2 OR 6386 X.25 ROUTER MPDM MPDM X.25 CARD NAU 3B2 OR 6386 X.25 ROUTER X.25 CARD LAN WITH StarGROUP NAU Figure 8-11. X.
PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS ________________________________________________________________________________________ ______________________________________________________________________________________ This section describes how to use public and private digital data networks to link DTEs and local area networks spread across a wide geographical area. These data networks ensure end to end digital transmission and can be packet-switched or circuit-switched.
8-22 PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ ports, although Memotec also has higher capacity units. (See figure 8-13.) SYSTEM 85 ASYNC ENDPOINTS 7400A, 7400B, ADU, OR MPDM MEMOTEC X.25 SP/630 PAD MODEM OR PRIVATE LINE APS X.25 •• X.
PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS 8-23 ________________________________________________________________________________________ ______________________________________________________________________________________ • Image viewing and transfer — Using slow-scan and freeze-frame capabilities, SDS and SDDN let senders and receivers jointly study databases, engineering drawings, and X-rays.
8-24 PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table 8-6.
PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS 8-25 ________________________________________________________________________________________ ______________________________________________________________________________________ MPDM, 7400A&B, 7500B DTE S85 G1/G2 PRI 4ESS POP PUBLIC SWITCHED DATA NETWORK (DOMESTIC) POP 4ESS PRI S85 G1/G2 MPDM, 7400A&B, 7500B DTE Figure 8-15.
8-26 PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ PRIVATE DATA NETWORKS AT&T leases facilities to private companies for nonswitched connections to private network endpoints.
PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS 8-27 ________________________________________________________________________________________ ______________________________________________________________________________________ Table 8-7. Requirements for PBX-to-PBX Private Network T1.
8-28 PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ 5. Also, supports 64-kbps 3270C/PC-PBX connections. 6. Older data modules (such as the DTDM, 7404 data module, and 7406 and 7407 data stands), can be used for Mode 2 connections. 7.
PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS 8-29 ________________________________________________________________________________________ ______________________________________________________________________________________ Private Terrestrial Connections Through ACCUNET Spectrum of Digital Services (ASDS) The requirements for using ASDS for PBX-to-PBX connections are given in table 8-8. Table 8-8.
8-30 PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DTE MPDM/M1* S75/S85 G1/G2 DS1 (ROBBED BIT) TRUNKS • DACS 4ESS POP VOICE CHANNELS AT&T PUBLIC NETWORK DATA CHANNELS PUBLIC SWITCHED DATA NETWORK DATA CHANNELS 4ESS POP DS1 (ROBBED BIT) TRUNKS S75/S85 G1
TELEMARKETING HOST CONNECTIONS ________________________________________________________________________________________ ______________________________________________________________________________________ A telemarketing host is a processor that is used for the online input of telephone transactions. To complete the online transaction screens that the host displays, a three-way interaction between the host, the agent, and the communications system takes place.
8-32 TELEMARKETING HOST CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ AT&T NETWORK 3B2 GATEWAY AT&T 3B2 COMPUTER AT&T SYSTEM 85 OR DEFINTY GENERIC 1 OR GENERIC 2 SOFTWARE APPLICATION ON HOST COMPUTER AGENT POSITIONS Figure 8-22.
TELEMARKETING HOST CONNECTIONS 8-33 ________________________________________________________________________________________ ______________________________________________________________________________________ For further details, see: • Integrated Telemarketing Gateway, System Description and Planning (585-246-202) • AT&T ISDN Gateway, Planning and Application Development (585-245-201)
8-34 TELEMARKETING HOST CONNECTIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
DATA NETWORK ADMINISTRATION ________________________________________________________________________________________ ______________________________________________________________________________________ The lines and trunks you use for data communication can be administered through the terminals and systems shown in table 2-4. In addition, you can use AT&T’s Unified Network Management Architecture (UNMA) ACCUMASTER tools for end-to-end control of your information network.
8-36 DATA NETWORK ADMINISTRATION _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
9. DATA COMMUNICATIONS CONFIGURATIONS ________________________________________________________________________________________ ______________________________________________________________________________________ Chapter 8 described how DTEs and LANs can communicate through your communications system. In addition, it told you how your communications system could communicate over greater distances using any of the ACCUNET data services.
9-2 DATA COMMUNICATIONS CONFIGURATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DSC AND PSC CONNECTIONS The dedicated switched connection (DSC) is a feature that provides a dedicated path using circuit-switched facilities on the System 85 (R2V4) and Generic 2 communications system; the permanent swit
DATA COMMUNICATIONS CONFIGURATIONS 9-3 ________________________________________________________________________________________ ______________________________________________________________________________________ ORIGINATING DATA MODULE HIGH-USAGE DATA TERMINAL MADU SUPPORTS ASYNCHRONOUS ONLY S75/G1 MPDM MADU EIA INTERFACE DIGITAL LINE PORT HOST COMPUTER OR FRONT-END PROCESSOR PSC — ALSO REFERRED TO AS "SOFTWARE CONNECTION" A.
9-4 DATA COMMUNICATIONS CONFIGURATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ HOST COMPUTER S75/S85/G1/G2 PSC OR DSC MADU EIA INTERFACE EIA UP TO 19.2-KBPS ASYNC MADU DS1 SWITCH COMPUTER OR PRINTER SWITCH (24TH-CHANNEL OR ISDN PRI MOS SIGNALING COMMUNICATION TYPE MUST BE AVD OR DATA) D.
DATA COMMUNICATIONS CONFIGURATIONS 9-5 ________________________________________________________________________________________ ______________________________________________________________________________________ SNA NODE CONNECTIONS You can use your communications system to connect the nodes in your SNA network. To do this, you use a dedicated connection (DSC or PSC) through the communicating switches. A workable configuration is shown in figure 9-2, although other configurations are possible.
9-6 DATA COMMUNICATIONS CONFIGURATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ CONNECTIONS THROUGH PUBLIC OR PRIVATE DATA NETWORKS You can connect your local communications systems with each other through DS1 facilities over public or private data networks for file transfers, video teleconferencing,
DATA COMMUNICATIONS CONFIGURATIONS 9-7 ________________________________________________________________________________________ ______________________________________________________________________________________ ACCUNET MPDM* ACCUNET MPDM* PICTURETEL SYSTEM 75/ SYSTEM 85/ GENERIC 1/ GENERIC 2 DS1 SWITCHED DIGITAL NETWORK DS1 SYSTEM 75/ SYSTEM 85/ GENERIC 1/ GENERIC 2 ACCUNET MPDM* ACCUNET MPDM* PICTURETEL *Also called MPDM/M1*. Figure 9-4.
9-8 DATA COMMUNICATIONS CONFIGURATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ OPTICAL SCANNER SERVER GATEWAY T1 MUX CAD/ IMAGE SERVER T1 MUX DS1 DS1 FILM SCANNER DATA NETWORK OPTICAL STORAGE DDS DS1 IMAGE PROCESSOR LAN ACCUNET MPDM GATEWAY DSU WITH RS366 S75/S85/ G1/G2 F E P IBM HOS
A.
A-2 RELATED DOCUMENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ AT&T DR23N Marketing Guide (350-068) D4 Channel Bank Description (365-170-100) Switched-On Data (451-400) Digital Multiplexed Interface Technical Specification Issue 3.
RELATED DOCUMENTS A-3 ________________________________________________________________________________________ ______________________________________________________________________________________ A Guide to Premises Distribution (555-400-021) Multiple Asynchronous Data Unit User Manual (555-401-702) Z3A Asynchronous Data Unit Product Manual (555-401-708) Introduction to ACCUMASTER Trouble Tracker (585-225-020) Private Network Management (5CE-054) 551 T1 Channel Service Unit User’s Manual (999-100-189IS)
A-4 RELATED DOCUMENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DIMENSION Administration Administration and Maintenance Manual — System Administration Procedures (500-915 to 917) RMATS-1 — Description, Operation, Maintenance, and Installation (554-010-130) Feature Translations for DIMENSION 600 (554-1
RELATED DOCUMENTS A-5 ________________________________________________________________________________________ ______________________________________________________________________________________ System 75, System 85, and DIMENSION PBX Systems — Application Notes — Trunk Signaling and Transmission ( 555-025-205) SYSTEM 75 AND GENERIC 1 Administration PC/PBX Connection Switch Administration for Packages 1, 3, and 5 (555-016-501) System 75 Implementation Manual Release 1 Version 3 (555-200-652) Applicatio
A-6 RELATED DOCUMENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ DEFINITY Communications System and System 75 and System 85 Terminals and Adjuncts (555-015-201) DEFINITY Communications System and System 75 and System 85 DS1/DMI/ISDN PRI (555-025-101) System 75 and 85 Connectivity Certification Mult
RELATED DOCUMENTS A-7 ________________________________________________________________________________________ ______________________________________________________________________________________ Sales Data Switching Sales Guide (555-035-001) Data Switching Applications (555-035-002) Service Communications System and System 75 and System 85 Terminals and Adjuncts Installation and Tests (555-015-104) DEFINITY ISDN Terminal Installation and Tests (555-021-101) SYSTEM 85 AND GENERIC 2 Administration PC/P
A-8 RELATED DOCUMENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ System 85 7434 Voice Terminal Application Notes (555-109-003) System 85 7400A Data Module Host Access Operation Application Notes (555-109-004) System 85 7400A Data Module External Modem Pooling Operation Application Notes (555-109-005) V
RELATED DOCUMENTS A-9 ________________________________________________________________________________________ ______________________________________________________________________________________ System 85 R2V4 to 740 Multiplexer (555-037-214) System 85 R2V4 to CSU (555-037-215) System 85 R2V4 to DR23n Microwave (555-037-216) System 85 R2V4 to 4ESS Via ISDN PRI Access (555-037-232) System 85 R2V4 to DEFINITY Generic 1.
A-10 RELATED DOCUMENTS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
B. SYNCHRONIZATION OF DIGITAL FACILITIES ________________________________________________________________________________________ ______________________________________________________________________________________ The DS1 transmit and receive buffers (for Generic 1 and Generic 2) operate from a single external or internal clock. Each digital switch can accommodate multiple DS1 or T1 spans that link multiple switches. These may include both ISDN-PRI and DS1 links.
B-2 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ systems connected by T1-carrier facilities. For this arrangement, the transmitting portion of each channel bank independently determines the clock rates.
SYNCHRONIZATION OF DIGITAL FACILITIES B-3 ________________________________________________________________________________________ ______________________________________________________________________________________ Notice in figure B-1-B, Options for Synchronization, that the overrun or underrun problem can be prevented by forcing the channel bank transmitter to operate at the same clock rate as the receive portion of the channel bank. This arrangement is called channel-bank loop timing.
B-4 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ For the hierarchical method, a node containing a very stable reference frequency is identified as the source or master reference.
SYNCHRONIZATION OF DIGITAL FACILITIES B-5 ________________________________________________________________________________________ ______________________________________________________________________________________ synchronized together. However, to provide higher quality synchronization performance, stratum-3 clocks are currently being used with some customer-premises equipment. Because of recent changes within the synchronization hierarchy, stratum-4 clocks are now defined as stratum-4E or stratum-4.
B-6 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ The public digital network nodes and services that the AT&T private digital switches and digital terminal products can connect to are as follows: • • • • DDS Digital serving office (DSO), also called a digital toll o
SYNCHRONIZATION OF DIGITAL FACILITIES B-7 ________________________________________________________________________________________ ______________________________________________________________________________________ STRATUM 1 AT&T STANDARD REFERENCE FREQUENCY DSO .. . . .. DEFINITY G1 OR G2 . .. .. . . .. . . .. . .. .. . .. .. .. .. SYSTEM 75 OR 85 DSO . . .. .. .. .. .. . .. . . .. . .. . . . . .. DCO . .. .. DSO .. .. .. STRATUM 2 DCO DACS DEFINITY . . . . . . SYSTEM . . .
B-8 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ TN463 CIRCUIT PACK STRATUM 4 HIGH ACCURACY CLOCK BACKPLANE CABLE TO PRIMARY DS1 INTERFACE (NOTE) BACKPLANE CABLE TO SECONDARY DS1 INTERFACE (NOTE) PRIMARY REFERENCE MAIN PHASE LOCKED LOOP MODULE CONTROL OR TMS CLO
SYNCHRONIZATION OF DIGITAL FACILITIES B-9 ________________________________________________________________________________________ ______________________________________________________________________________________ System 85 or Generic 2 with a duplicated architecture and cross-coupled cables. PRIMARY DS1 INTERFACE SCS 0 MODULE CLOCK OR TMS CLOCK 0 SWITCHING NETWORK 0 SECONDARY PORT CARRIERS PRIMARY SECONDARY DS1 INTERFACE SCS 1 MODULE CLOCK OR TMS CLOCK 1 SWITCHING NETWORK 1 Figure B-5.
B-10 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • • • • • • Red alarm means that two out of four (or worse) framing patterns were received.
SYNCHRONIZATION OF DIGITAL FACILITIES B-11 ________________________________________________________________________________________ ______________________________________________________________________________________ • The LED in position #5 refers to the secondary DS1 reference. The LED is OFF if a synchronization signal is present and the SCS is capable of locking. The #5 LED is ON if an error condition exists and the synchronization cable is present.
B-12 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ TN768 or TN780 CIRCUIT PACK EXTERNAL SYNC SOURCE EXTERNAL SYNC SOURCE STRATUM 4 ACCURACY CLOCK TONE GENERATOR PRIMARY REFERENCE MAIN PHASELOCKED LOOP MISCELLANEOUS TONES MAIN SYSTEM BUSS SECONDARY REFERENCE
SYNCHRONIZATION OF DIGITAL FACILITIES B-13 ________________________________________________________________________________________ ______________________________________________________________________________________ The TN768 and TN780 circuit packs contain edge-mounted LEDs. These LEDs indicate the following status sequences: • Yellow LED is on 2.7 seconds and off 0.3 seconds — the tone-clock synchronizer is in ‘‘active’’ mode and a DS1 is being used as a synchronization reference.
B-14 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ With automatic reference switching enabled, most Generic 1 error counters are decremented by 1 every 15 minutes and initialized to zero on reaching the threshold value.
SYNCHRONIZATION OF DIGITAL FACILITIES B-15 ________________________________________________________________________________________ ______________________________________________________________________________________ and secondary references also apply to these references. For System 85 and Generic 2, all functions previously performed by SCS synchronization software are now provided external to the switch — by the external clock.
B-16 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ STRATUM 3 REFERENCE #1 CLOCK INPUT #1 TIMING OUTPUT, COMPOSITE CLOCK B STRATUM 3 CLOCK A SYSTEM 85 AND GENERIC 2 ONLY PHASE BUILD OUT STRATUM 3 REFERENCE #2 TO TN2131 0 STRATUM 3 CLOCK B CLOCK INPUT #2 -48VD
SYNCHRONIZATION OF DIGITAL FACILITIES B-17 ________________________________________________________________________________________ ______________________________________________________________________________________ TN2131 CIRCUIT PACK COMPOSITE CLOCK OUTPUT A COMPOSITE CLOCK OUTPUT B COMPOSITE CLOCK CONVERTER LOS DETECTION ALARMS NOTE 1 BACKPLANE SIGNAL TO TMS OR MODULE CONTROL CLOCK SYNC OUTPUT NOTE 2 NOTES: 1. Alarm signals are cabled to the cross-connect field.
B-18 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ NETWORK SYNCHRONIZATION AND ENGINEERING The primary goals of network synchronization are: • To keep each digital network node reliable • To make sure that each digital termination can meet the network objectives With
SYNCHRONIZATION OF DIGITAL FACILITIES B-19 ________________________________________________________________________________________ ______________________________________________________________________________________ DIGITAL SERVING OFFICE EXTERNALLY REFERENCED NODES INTERNALLY REFERENCED NODES SYSTEM 85 OR 75 SYSTEM 85 OR 75 DIGITAL TRANSMISSION FACILITY PRIMARY FREQUENCY REFERENCE Figure B-11.
B-20 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ If there are one or more clocks in the network at the lowest stratum level, the following steps can be taken to determine the clock that should become the network reference clock source.
SYNCHRONIZATION OF DIGITAL FACILITIES B-21 ________________________________________________________________________________________ ______________________________________________________________________________________ RULE 2: A node may use a facility as a backup only if the node at the other end is not using that same facility as a backup. EXAMPLE FOR RULE 2 Figure B-13, Proper Use of Backup Facilities, illustrates an application of rule 2 and proper use of a backup facility between nodes A and C.
B-22 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ B A ................................. ................................. C D DIGITAL TRANSMISSION FACILITY PRIMARY FREQUENCY REFERENCE .................. SECONDARY (BACKUP) FREQUENCY REFERENCE Figure B-14.
SYNCHRONIZATION OF DIGITAL FACILITIES B-23 ________________________________________________________________________________________ ______________________________________________________________________________________ Facility rank ordering is generally based on limited technical and operational information. It is recommended that facility selections be based on local field experience where available.
B-24 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ A B ................................... C D DIGITAL TRANSMISSION FACILITY PRIMARY FREQUENCY REFERENCE ................. SECONDARY (BACKUP) FREQUENCY REFERENCE Figure B-16.
SYNCHRONIZATION OF DIGITAL FACILITIES B-25 ________________________________________________________________________________________ ______________________________________________________________________________________ A .. .. .. .. .. .. .. .. .. .. .. .. B D C DIGITAL TRANSMISSION FACILITY PRIMARY FREQUENCY REFERENCE .............. SECONDARY (BACKUP) FREQUENCY REFERENCE Figure B-17. Excessive Cascading A D .. .. .. . .. .. .. . .. . .. .. .. .
B-26 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ RULE 7: The number of nodes receiving synchronization reference from any given node should be minimized.
SYNCHRONIZATION OF DIGITAL FACILITIES B-27 ________________________________________________________________________________________ ______________________________________________________________________________________ A B C .... ... .... ... .... .... ... .... ... .... .... ... .... ... .... ... .... .... ... D E F DIGITAL TRANSMISSION FACILITY PRIMARY FREQUENCY REFERENCE .............. SECONDARY (BACKUP) FREQUENCY REFERENCE Figure B-20.
B-28 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ AVAILABILITY OF SYNCHRONIZATION SOURCES Misconception 1 The local exchange company (LEC) can always provide the synchronization source. Fact 1 The LECs are not always subscribers to the AT&T reference frequency.
SYNCHRONIZATION OF DIGITAL FACILITIES B-29 ________________________________________________________________________________________ ______________________________________________________________________________________ CONCLUSIONS ON SYNCHRONIZATION Make no assumptions regarding synchronization. Reverify items such as the availability of a synchronization source, the clock stratum, and compatibility of every T1 span.
B-30 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ only mode DS1s should not be used to determine the health of a clock reference (that is, they would tend to make the reference appear to be in better condition than it may be).
SYNCHRONIZATION OF DIGITAL FACILITIES B-31 ________________________________________________________________________________________ ______________________________________________________________________________________ Trunk-Mode Interface (ISDN-PRI + Robbed Bit) (TN767) Since it is expected that a trunk mode DS1 would terminate at a class-5 or higher CO or at another switch, the trunk interface should be suitable for use as a primary or secondary clock reference (or to be the timing master for another swi
B-32 SYNCHRONIZATION OF DIGITAL FACILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
C. TRUNKING TERMS AND CAPABILITIES ________________________________________________________________________________________ ______________________________________________________________________________________ This appendix contains a list of trunking-related terms. The terms are listed in alphabetical order and should serve as a supplement to the glossary.
C-2 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Alerting Signals Functions to establish the way information is sent and received across trunks, once they are seized. For tie trunks, there exist five different alerting signals.
TRUNKING TERMS AND CAPABILITIES C-3 ________________________________________________________________________________________ ______________________________________________________________________________________ CCSA (or Common Control Switching Arrangement) A private network configuration in which switching is provided by one or more CO switches. Typically, these CO switches may be shared by other private networks as well as by the public switched telephone network.
C-4 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Delay-Dial The method of alerting whereby the originating switch waits for the terminating switch to acknowledge (via a start-dial signal) that it is ready to receive the address digits.
TRUNKING TERMS AND CAPABILITIES C-5 ________________________________________________________________________________________ ______________________________________________________________________________________ Derived E&M Lead Signaling A signaling interface arrangement where the basic E&M interface is modified so that the E&M leads derive/superimpose either simplex, duplex, or composite type signals.
C-6 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Direct Access Refer to ‘‘Special Access Connections.’’ EPSCS (or Enhanced Private Switched Communications Service) A private network configuration in which switching is provided by one or more CO switches.
TRUNKING TERMS AND CAPABILITIES C-7 ________________________________________________________________________________________ ______________________________________________________________________________________ (4) All out-of-building (inter-building) applications should have lightning protection optioned. Note: For System 85 and Generic 2 traditional module trunks, the method of selecting E&M options involves configuring DIP switches on the SN circuit pack.
C-8 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Glare A problem that can occur with any 2-way trunks. Glare occurs when both ends seize the same trunk circuit simultaneously. Glare is more likely to occur with loop start than other types of trunks.
TRUNKING TERMS AND CAPABILITIES C-9 ________________________________________________________________________________________ ______________________________________________________________________________________ (3) If the other entity is a PBX, either encode may be used by mutual agreement; however, they must be opposite for the trunk to work at all.
C-10 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • 100-milliseconds——for DIMENSION PBX switches. Interdigit Time-out The maximum number of seconds that the switch can wait from one digit to the next digit before a time-out occurs and a retry is required.
TRUNKING TERMS AND CAPABILITIES C-11 ________________________________________________________________________________________ ______________________________________________________________________________________ Main PBX In a main—satellite/tributary communications network, it is the primary (main) node that handles all trunk traffic for the connected satellite and tributary switches.
C-12 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Note: System 75 R1V1 DOES NOT SUPPORT precise dial tone. Therefore, it is recommended that the distant switch be optioned to provide the R1V1 switch with a dc signal (e.g.
TRUNKING TERMS AND CAPABILITIES C-13 ________________________________________________________________________________________ ______________________________________________________________________________________ Signaling Type With System 85 (R2V4) and the Generic 2 communications system, the switch provides the capability to administer a different signaling type (e.g., E&M, ground start, etc.) from that implied by or defaulted by the trunk type.
C-14 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Touch-Tone Signaling Refer to DTMF.
TRUNKING TERMS AND CAPABILITIES C-15 ________________________________________________________________________________________ ______________________________________________________________________________________ Note: Previously, most switch implementations of the universal trunk type have not actually timed for a precise wink signal. However, they do provide dial-tone detection for subnet trunk groups.
C-16 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ SUGGESTIONS AND HELPFUL HINTS (1) Given a choice of multiple trunk supervision methods—E&M generally works best.
TRUNKING TERMS AND CAPABILITIES C-17 ________________________________________________________________________________________ ______________________________________________________________________________________ TRUNKING CHARACTERISTICS TABLE D ——identifies the DEFAULT supervision option on the Generic 2 for the associated trunk group type and the only option for R2V3 and earlier releases.
C-18 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-19 ________________________________________________________________________________________ ______________________________________________________________________________________ _______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-20 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-21 ________________________________________________________________________________________ ______________________________________________________________________________________ ______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-22 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-23 ________________________________________________________________________________________ ______________________________________________________________________________________ ______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-24 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-25 ________________________________________________________________________________________ ______________________________________________________________________________________ _______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-26 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-27 ________________________________________________________________________________________ ______________________________________________________________________________________ _______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-28 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-29 ________________________________________________________________________________________ ______________________________________________________________________________________ _______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-30 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _______________________________________________________________________________________ SWITCH A FOR EACH "SWITCH A" TRUNKING OPTION (LISTED BELOW) — REFER TO THE CORRESPONDING RECOMMENDED "SWITCH B" TRU
TRUNKING TERMS AND CAPABILITIES C-31 ________________________________________________________________________________________ ______________________________________________________________________________________ _______________________________________________________________________________________ SWITCH B RECOMMENDED TRUNK OPTIONS — OTHER OPTIONS MAY WORK FOR SOME APPLICATIONS; HOWEVER THESE OPTIONS SHOULD ALWAYS WORK.
C-32 TRUNKING TERMS AND CAPABILITIES _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
D. COMMUNICATIONS PROTOCOLS ________________________________________________________________________________________ ______________________________________________________________________________________ A protocol is a set of rules for how transmissions are to be initiated and maintained between communication points. These rules are conventions that govern the syntax and sequencing of messages. Several domestic and international organizations formulate standards for data communications protocols.
D-2 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ OSI MODEL To provide a model through which all protocols could be classified and studied, the International Organization for Standardization (ISO) created the Open Systems Interconnection (OSI) architecture.
COMMUNICATIONS PROTOCOLS D-3 ________________________________________________________________________________________ ______________________________________________________________________________________ LEVEL 7 APPLICATION LAYER LEVEL 6 PRESENTATION LAYER LEVEL 5 SESSION LAYER LEVEL 4 TRANSPORT LAYER LEVEL 3 NETWORK LAYER LEVEL 2
D-4 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Figure D-1.
COMMUNICATIONS PROTOCOLS D-5 ________________________________________________________________________________________ ______________________________________________________________________________________ Session Layer The session layer, or layer 5, provides a mechanism for controlling dialogue between applications. It establishes, manages, and terminates connections between cooperating applications.
D-6 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table D-1.
COMMUNICATIONS PROTOCOLS D-7 ________________________________________________________________________________________ ______________________________________________________________________________________ Table D-2.
D-8 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ TABLE D-2.
COMMUNICATIONS PROTOCOLS D-9 ________________________________________________________________________________________ ______________________________________________________________________________________ Application Presentation Session End-to-end user signaling CCITT-ISO OSI-related protocols Transport Network Call control I.451 Data link X.25 Packet level ( Further study ) X.25 Packet level X.25 LAP-B LAP-D (I.441) Physical Layer 1 (I.430, I.
D-10 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • ADCCP (Advanced data communications control procedures) — A protocol developed by ANSI, and later adopted by the National Bureau of Standards, the Federal Communications Standards Committee, and the Defense Department.
COMMUNICATIONS PROTOCOLS D-11 ________________________________________________________________________________________ ______________________________________________________________________________________ • The Bell standard for X.25 (BX.25) The primary rate interface standard is the ISDN standard for communication along a DS1 facility. AT&T has its own implementation of this standard.
D-12 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ —Requires a ‘‘circuit-switched’’ transmission facility Applications: There are two uses of mode 0. They are: (a) 8-bit PCM voice (no robbed-bit or inband signaling is allowed) (b) 64-kbps user data.
COMMUNICATIONS PROTOCOLS D-13 ________________________________________________________________________________________ ______________________________________________________________________________________ data frames are multiplexed into a DCP and DS1 frame. The state of the status bit along with its transition from one frame to another frame is used to convey the state of the following RS-449/V.
D-14 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Data Mode 2 Capabilities: —Low, 300, 1200, 2400, 4800, 9600, or 19.
COMMUNICATIONS PROTOCOLS D-15 ________________________________________________________________________________________ ______________________________________________________________________________________ FLAG 01111110 E SPARE SCA S DATA/CONTROL CRC VARIABLE LENGTH Figure D-4. Data mode 2 Frame Structure Note: For asynchronous data, the SCA field is left spare. The data/control field is a variable length field.
D-16 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ • CD • CA. Also, the update messages support three special control functions.
COMMUNICATIONS PROTOCOLS D-17 ________________________________________________________________________________________ ______________________________________________________________________________________ The DCP protocol physical level requires a 4-wire data link. Therefore, the data link must be composed of at least two twisted pairs. The physical interface may include additional wire pairs for spares and auxiliary power functions.
D-18 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ _____________________________________________________ Transmit Pair 1&2 3&6 _____________________________________________________ Receive Pair 3&6 4&5 _____________________________________________________ I
COMMUNICATIONS PROTOCOLS D-19 ________________________________________________________________________________________ ______________________________________________________________________________________ Physical Layer. This layer for BX.25 is compatible with the RS-232C and RS-449 standards. Data-Link Layer. At this layer, BX.25 uses a procedure is compatible with the HDLC (High-Level Data Link Control) procedure and is performed by DCIU firmware and by an HDLC chip on each of the DCIUs eight links.
D-20 COMMUNICATIONS PROTOCOLS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Message, Packet, and Frame The units of information in BX.25 are the message, the packet, and the frame. Starting with the data that an application (e.g.
E. LEAD DEFINITIONS ________________________________________________________________________________________ ______________________________________________________________________________________ This appendix provides tables that list the lead definitions for the most common physical interfaces.
E-2 LEAD DEFINITIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table E-1. EIA RS-232C (V.28) LEADS/DEFINITIONS ________________________________________________________________ PIN EIA CCITT LEAD DESCRIPTION NO.
LEAD DEFINITIONS E-3 ________________________________________________________________________________________ ______________________________________________________________________________________ Table E-2. EIA RS-232D (V.28) LEADS/DEFINITIONS ______________________________________________________________________ PIN EIA CCITT LEAD DESCRIPTION NO.
E-4 LEAD DEFINITIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table E-3. EIA RS-449 (V.
LEAD DEFINITIONS E-5 ________________________________________________________________________________________ ______________________________________________________________________________________ Table E-4. EIA RS-366 LEADS/DEFINITIONS ___________________________________________________ PIN LEAD DESCRIPTION MPDM EIA NO.
E-6 LEAD DEFINITIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Table E-5. CCITT V.35 LEADS/DEFINITIONS ______________________________________________________________________ PIN MPDM CCITT EIA LEAD DESCRIPTION NO.
LEAD DEFINITIONS E-7 ________________________________________________________________________________________ ______________________________________________________________________________________ Table E-6. EIA RS-232C (V.28) LEADS SUPPORTED FOR AT&T TERMINALS _____________________________________________________________________ PIN PC 6300/ DTDM/ PDM/ TDM/ ADU/MADU PC 7300 _____________________________________________________________________ (NOTE 1) NO.
E-8 LEAD DEFINITIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Notes: 1. The SN238 and TN726 circuit packs provide the same signal leads as the ADU/MADU. 2. This lead is ignored in MODE 2 operation. 3. These leads are tied together on this terminal. 4. This lead is used for speed mode indication. 5.
F. NETWORKING FEATURES——AVAILABILITY MATRIX ________________________________________________________________________________________ ______________________________________________________________________________________ The following list compares the network features available in the AT&T private switching systems. In the list NA = NOT APPLICABLE; Y = YES; N = NO.
F-2 NETWORKING FEATURES——AVAILABILITY MATRIX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ __________________________________________________________________________________ ‘‘DIMENSION’’ DEFINITY SYSTEM 85 SYSTEM 75 FEATURE PBX ___________________________________________
NETWORKING FEATURES——AVAILABILITY MATRIX F-3 ________________________________________________________________________________________ ______________________________________________________________________________________ NETWORKING FEATURES——AVAILABILITY MATRIX (Contd) ___________________________________________________________________________________________ ‘‘DIMENSION’’ DEFINITY SYSTEM 85 SYSTEM 75 FEATURE PBX __________________________________________________________
F-4 NETWORKING FEATURES——AVAILABILITY MATRIX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ NETWORKING FEATURES——AVAILABILITY MATRIX (Contd) ____________________________________________________________________________________ ‘‘DIMENSION’’ DEFINITY SYSTEM 85 SYSTEM 75 FEATURE
NETWORKING FEATURES——AVAILABILITY MATRIX F-5 ________________________________________________________________________________________ ______________________________________________________________________________________ NETWORKING FEATURES——AVAILABILITY MATRIX (Contd) ________________________________________________________________________________ ‘‘DIMENSION’’ SYSTEM 75 DEFINITY SYSTEM 85 FEATURE PBX _______________________________________________________________
F-6 NETWORKING FEATURES——AVAILABILITY MATRIX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
ABBREVIATIONS ________________________________________________________________________________________ ______________________________________________________________________________________ 4ESS number 4 electronic switching system 5ESS number 5 electronic switching system AAR Automatic Alternate Routing ACA Automatic Circuit Assurance ACD Automatic Call Distribution ACP action control point (for SDN) ADPCM adaptive differential pulse-code modulation ADU asynchronous data unit AMI alterna
AB-2 ABBREVIATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ CO central office CRC cyclic redundancy check CSM Centralized System Management CSU customer service unit DAC dial access code DACS digital access and crossconnect system DCE data circuit-terminating equipment data communications
ABBREVIATIONS AB-3 ________________________________________________________________________________________ ______________________________________________________________________________________ ETA extended trunk access ETN electronic tandem network FAX facsimile FEP front end processor FP8 feature package 8 (for DIMENSION) FRL facility restriction level FX foreign exchange G1/G2 Generic 1/Generic 2 GPP general-purpose port Gbps billion bits per second HAC high accuracy clock HEHO h
AB-4 ABBREVIATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ MPDM modular processor data module MS/T main satellite/tributary network MTDM modular trunk data module Mbps million bits per second NCP network control point (for SDN) NID network inward dialing OSI Open Systems Interconnection
ABBREVIATIONS AB-5 ________________________________________________________________________________________ ______________________________________________________________________________________ SDN Software-Defined Network SMT system management terminal SNA Systems Network Architecture SO serving office (for SDN) SW56 Switched 56 ACCUNET Service SW64 Switched 64 ACCUNET Service TEHO tail end hop off TSI time slot interchange unit TTT tandem tie trunk (network) UDP Uniform Dial Plan (pac
AB-6 ABBREVIATIONS _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________
GLOSSARY ________________________________________________________________________________________ ______________________________________________________________________________________ 24th-channel signaling Digital signal level-1 (DS1) signaling in which the signaling for each of the first 23 channels is multiplexed onto the 24th channel, thereby providing a full 64 kbps for user data on each of the first 23 channels. Also called clear-channel signaling.
GL-2 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ American National Standard Code for Information Interchange See ASCII. analog The representation of information by means of continuously varying physical quantities such as amplitude, frequency, phase, or resistance.
GLOSSARY GL-3 ________________________________________________________________________________________ ______________________________________________________________________________________ AUDIX Standalone An AUDIX system that has no data link and allows AUDIX service to be provided in association with any communications system but with less functionality than when AUDIX is integrated via a data link with a communications system. See also AUDIX.
GL-4 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ bearer capability A term used with Integrated Services Digital Networks (ISDNs) to identify the kinds of service that are requested or are available for a call. See also bearer-capability class.
GLOSSARY GL-5 ________________________________________________________________________________________ ______________________________________________________________________________________ BRI See basic rate interface. BSC See binary synchronous communications. BX.25 An AT&T version of the CCITT X.25 protocol for data communications. BX.25 adds a fourth level to the standard X.25 interface.
GL-6 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ class of service (COS) 1. On the System 75 and Generic 1, a number (0 through 15) that specifies a group of feature-access permissions of a group of telephones.
GLOSSARY GL-7 ________________________________________________________________________________________ ______________________________________________________________________________________ CSU The terms channel service unit and customer service unit are both abbreviated to CSU and are both synonymous with network channelterminating equipment. See network channel-terminating equipment.
GL-8 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ data communications interface unit (DCIU) An interface between the System 85 main processor (501CC) and AUDIX equipment, or (in a DCS configuration) other switches.
GLOSSARY GL-9 ________________________________________________________________________________________ ______________________________________________________________________________________ DDC See Direct Department Calling. DDD See direct distance dialing. dedicated line Also known as a private or leased line. It is for the exclusive use of the leasing party.
GL-10 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ digital multiplexed interface (DMI) An interface that provides connectivity between a communications system and a host computer or between two communications systems using digital signal level-1 (DS1) 24th-channel signaling.
GLOSSARY GL-11 ________________________________________________________________________________________ ______________________________________________________________________________________ direct outward dialing (DOD) A feature that enables a communications-system telephone user to gain access to the public network without the assistance of an attendant by dialing an access code and receiving a second dial tone. The user can then dial the desired public-network number.
GL-12 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ end user The ultimate source or destination of information flowing through a network. It may be an application program, an operator or a physical device medium (such as cards or tapes).
GLOSSARY GL-13 ________________________________________________________________________________________ ______________________________________________________________________________________ final trunk group A last-choice trunk group that receives overflow traffic and may receive first-route traffic. See also trunk group. first-choice trunk group The group of trunks on a communications system that is chosen first for a particular call. See also trunk group. flexible assignment of BX.
GL-14 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ GPP See general-purpose port. half-duplex transmission A transmission system capable of carrying signals in both directions, but in only one direction at a time.
GLOSSARY GL-15 ________________________________________________________________________________________ ______________________________________________________________________________________ Integrated Services Digital Network (ISDN) A public or private network that provides end-to-end digital connectivity for all services to which users have access by a limited set of standard multipurpose user-network interfaces defined by the CCITT.
GL-16 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ listed directory number (LDN) The listed number in a public directory for a communications system. An incoming call to an LDN is usually answered by an attendant.
GLOSSARY GL-17 ________________________________________________________________________________________ ______________________________________________________________________________________ MPDM See modular processor data module. MTDM See modular trunk data module. mu-255 A type of code by which analog signals are encoded to digital signals. multiplexer A device used to combine a number of individual channels into a common bit stream for transmission.
GL-18 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ Open Systems Interconnection (OSI) reference model A logical model, consisting of seven levels of interfaces, created by the International Standards Organization (ISO) to show how interconnected telecommunications systems should interface.
GLOSSARY GL-19 ________________________________________________________________________________________ ______________________________________________________________________________________ permanent switched connection (PSC) On the System 75 and Generic 1, a capability that establishes and maintains a continuous switched connection between two data endpoints. PSCs are automatically established when the communications system is started or restarted, and are maintained until the system becomes inactive.
GL-20 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ protocol converter (PC) A device consisting of hardware, software, or a combination of both, that allows two systems, each using a different protocol, to communicate and exchange messages with each other.
GLOSSARY GL-21 ________________________________________________________________________________________ ______________________________________________________________________________________ route advance A telecommunications routine that routes outgoing calls over alternate trunk groups when the first-choice trunk group is busy. RS-232 A physical interface specified by the EIA. RS-232 transmits and receives asynchronous data at speeds of up to 19.2 kbps over cable distances of up to 50 feet.
GL-22 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ switch Any kind of telephone switching system. See also communications system and ESS.
GLOSSARY GL-23 ________________________________________________________________________________________ ______________________________________________________________________________________ tip and ring Tip and ring are common nomenclature derived from old cord switchboard technology to differentiate between the two leads of an analog line or trunk. trunk A dedicated telecommunications channel between two communications systems or central offices (COs). See also facility.
GL-24 GLOSSARY _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ WATS (Wide Area Telecommunications Service) A service that allows calls to certain areas for a flat-rate charge based on expected usage.
INDEX ________________________________________________________________________________________ ______________________________________________________________________________________ 1 10-to-7 digit conversion 2-14 2 24th channel signaling 1-27 2-wire trunk C-1 3 3270C 8-6 4 4-wire link 7-5, D-17 4-wire trunk C-1 7 718 Stat Mux 1-34 719 Networker 1-34 7400A 8-6 7400B 8-6 7500B 8-6 8 800 service 1-36 A AAR 2-5, 2-6, 2-7, 2-8, 2-11, 2-13, 4-4, 4-7, 4-8, 5-1, 5-13 ACA 6-15 access code AAR 2-6, 4-7 dial 2
IN-2 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ ARS 2-4, 2-7, 2-8, 2-14 plan 2-16 asynchronous data-module 8-5 Asynchronous Gateway Server 8-16 AT&T reference frequency B-28 attendant 1-37, 2-2, 4-1, 4-3, 4-8, 5-12, 6-23 control of trunk group access 6-15 transparent features 6-14 attendant-call-wa
INDEX IN-3 ________________________________________________________________________________________ ______________________________________________________________________________________ compression—Contd BCM-3200 1-31 channel expansion multiplexer 1-31 conditional call routing count 2-10 configuration main/satellite 4-2 main/tributary 4-3 connection dedicated 9-5 dedicated switched 6-4, 7-8, 9-2 dial-up 7-8 nailed-up 7-8, C-13 permanent switched 6-4, 7-8, 9-2 SNA node 9-5 special access C-13 controlled sl
IN-4 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ dial tone C-5, C-11 alerting 1-40 dialing C-14 computer 7-10 terminal 7-9 basic 7-9 break signal 7-9 default 7-9 Hayes-AT 7-9 mnemonic 7-9 dial-repeating 1-40 DID 1-36, 4-2, C-5 digital telephones 1-7 facilities, synchronization of B-1 multiplexed int
INDEX IN-5 ________________________________________________________________________________________ ______________________________________________________________________________________ fiber-optic transmission 1-32, 8-14 file transfer 8-22, 9-6 fractional T1 8-26 frame 1-24 D4 1-24, 1-27, 1-29 ESF 1-24, 1-27, 1-29 synchronization pattern 1-25 framing formats 1-24 free run ability B-4 frequency-division multiplexing 1-17 FRL 2-10, 2-13, 2-16 default 2-10 FT-1 1-32 full-duplex communication 7-2, 7-5 G gat
IN-6 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ line-only-mode B-29 line-+trunk-mode B-30 link synchronization B-1 link-layer protocols D-2, D-9, D-19 listed directory number 4-1, 4-2, 4-3 local area network 7-2, 8-13 logical channel 6-3, D-19 long distance facilities 5-9 loop start 1-40 LOS B-9, B
INDEX IN-7 ________________________________________________________________________________________ ______________________________________________________________________________________ network—Contd synchronization—Contd plan—Contd example B-20 issues B-1 tandem tie trunk 1-36, 2-2, 3-1, C-13 tuning B-29 network-layer protocols D-2 NFAS 1-28 NID 4-2 node connections, cascade B-24 noise 1-6 number international 2-14 IXC 2-14 listed directory 4-1, 4-2, 4-3 local 2-14 O OCU data port card 1-30 off-hook 8-1
IN-8 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ protocols—Contd layer 2 1-11 link layer 1-11 network layer D-2 Open System Interconnect 1-11 OSI 1-11 physical interface 1-13 physical layer 1-11, 1-15, D-2, D-9 presentation layer D-5 PRI 1-13, D-11 RS-232C 1-13, 6-3 RS-449 1-13, 6-3 ACCUNET modific
INDEX IN-9 ________________________________________________________________________________________ ______________________________________________________________________________________ signaling—Contd address C-1 DTMF C-3 AVD 1-41 common channel signaling arrangement C-3 DMI BOS 1-27 DMI MOS 1-27 DX C-3 E&M 1-39, C-3, C-5, C-6 facility associated 1-28 ground start 1-39 inband 1-26 ISDN PRI 1-27 loop start 1-40, C-10 nonfacility associated 1-28 out-of-band C-11 proprietary 1-27 RBS 1-26 reverse battery 1-
IN-10 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________ synchronous transmission B-1 system clock reference using Generic 1 B-30 using Generic 2 B-29 System 75 and Generic 1 synchronization architecture B-11 and Generic 1 synchronization software operation B-12 T T1 carrier 1-6, 1-18, 1-32 compression
INDEX IN-11 ________________________________________________________________________________________ ______________________________________________________________________________________ trunk—Contd 4-wire C-1 800 service 1-36 analog 1-9, 1-15 APLT 1-38 application 1-35 auxiliary 1-10, 1-35, 1-37 CCSA 1-38 central office 1-35 CO 1-10 communications type 1-41 connectivity 1-38 DID 1-10, 1-36, C-5 digital 1-9 DMI 1-40 DOD 1-36 DS1 1-10, 1-15, 1-41, 6-4, 7-8 EPSCS 1-38 ETN C-7 foreign exchange 1-35 FX C-7 gr
IN-12 INDEX _____________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________