SIM800_Hardware Design_V1.
Smart Machine Smart Decision Document Title SIM800 Hardware Design Version 1.05 Date 2014-03-25 Status Release Document Control ID SIM800_Hardware Design_V1.05 General Notes SIMCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by SIMCom. The information provided is based upon requirements specifically provided to SIMCom by the customers.
Smart Machine Smart Decision Contents Version History ........................................................................................................................................................ 9 1. Introduction ................................................................................................................................................. 10 2. SIM800 Overview ...................................................................................................................
Smart Machine Smart Decision 4.10.4. SD Card Interface ............................................................................................................................ 44 4.11. Keypad Interface .................................................................................................................................... 44 4.12. I2C BUS ................................................................................................................................................. 47 4.13.
Smart Machine Smart Decision Table Index TABLE 1: SIM800 KEY FEATURES.............................................................................................................................. 10 TABLE 2: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ............................ 12 TABLE 3: OVERVIEW OF OPERATING MODES........................................................................................................ 12 TABLE 4: PIN DESCRIPTION .........................................
Smart Machine Smart Decision TABLE 47: GSM 900 AND GSM 850 CONDUCTED RF OUTPUT POWER .............................................................. 59 TABLE 48: DCS 1800 AND PCS 1900 CONDUCTED RF OUTPUT POWER............................................................. 60 TABLE 49: CONDUCTED RF RECEIVE SENSITIVITY ............................................................................................. 60 TABLE 50: OPERATING FREQUENCIES...................................................................
Smart Machine Smart Decision Figure Index FIGURE 1: SIM800 FUNCTIONAL DIAGRAM ........................................................................................................... 13 FIGURE 2: SIM800 PIN OUT DIAGRAM (TOP VIEW) ............................................................................................... 14 FIGURE 3: DIMENSIONS OF SIM800 (UNIT: MM) ....................................................................................................
Smart Machine Smart Decision FIGURE 47: GSM ANTENNA MATCHING CIRCUIT ................................................................................................. 52 FIGURE 48: GSM SIMPLE ANTENNA MATCHING CIRCUIT .................................................................................. 52 FIGURE 49: BLUETOOTH ANTENNA MATCHING CIRCUIT .................................................................................. 53 FIGURE 50: TOP AND BOTTOM VIEW OF SIM800 ...................................
Smart Machine Smart Decision Version History Date Version Description of change Author 2013-07-29 1.00 Origin Ma Honggang Teng Lili 2013-08-05 1.01 Update RESET pin parameter; Update figure 12, 13, 15. Ma Honggang 2013-08-21 1.02 Update figure 3 and figure 23; Update chapter 7.3; Ma Honggang 2014-01-17 1.03 Update table32, correct NETLIGHT to PIN 52; Ma Honggang 2014-03-11 1.04 Update table 11 Ma Honggang 2014-03-25 1.
Smart Machine Smart Decision 1. Introduction This document describes SIM800 hardware interface in great detail. This document can help user to quickly understand SIM800 interface specifications, electrical and mechanical details. With the help of this document and other SIM800 application notes, user guide, users can use SIM800 to design various applications quickly. 2.
Smart Machine Smart Decision Transmitting power z z Class 4 (2W):GSM850,EGSM900 Class 1 (1W):DCS1800,PCS1900 GPRS connectivity z z GPRS multi-slot class 12（default） GPRS multi-slot class 1~12 (option) z z Normal operation:-40°C ~ +85°C Storage temperature -45°C ~ +90°C z z z z z z z GPRS data downlink transfer: max. 85.6 kbps GPRS data uplink transfer: max. 85.6 kbps Coding scheme: CS-1, CS-2, CS-3 and CS-4 PAP protocol for PPP connect Integrate the TCP/IP protocol.
Smart Machine Smart Decision Table 2: Coding schemes and maximum net data rates over air interface Coding scheme 1 timeslot 2 timeslot 4 timeslot CS-1 9.05kbps 18.1kbps 36.2kbps CS-2 13.4kbps 26.8kbps 53.6kbps CS-3 15.6kbps 31.2kbps 62.4kbps CS-4 21.4kbps 42.8kbps 85.6kbps 2.2. Operating Modes The table below summarizes the various operating modes of SIM800.
Smart Machine Smart Decision 2.3. SIM800 Functional Diagram The following figure shows a functional diagram of SIM800: z GSM baseband engine z Flash z GSM RF part z Antenna interfaces z Other interfaces Figure 1: SIM800 functional diagram SIM800_Hardware Design_V1.
Smart Machine Smart Decision 3. Package Information 3.1. Pin Out Diagram Figure 2: SIM800 pin out diagram (Top view) SIM800_Hardware Design_V1.
Smart Machine Smart Decision 3.2. Pin Description Table 4: Pin description Pin name Pin number I/O Description Comment I SIM800 supplies 3 VBAT pins, and the power range is from 3.4V to 4.4V. Power supply should provide sufficient current so that the module can work normally; the peak current is nearly 2A. Zener diode is Strongly recommended to anti surge on VBAT. Power supply VBAT 55,56,57 VRTC 26 I/O Power supply for RTC It is recommended to connect VRTC to a battery or a capacitor (e.g.
Smart Machine Smart Decision ROW2 42 O ROW1 43 O ROW0 44 O GPIO17 11 I/O GPIO19 13 I/O Programmable output.
Smart Machine Smart Decision I/O Connect Bluetooth antenna Impendence must be controlled to 50Ω. 67 O RF burst synchronous signal Do not pull up RESET 16 I Reset input(Active low) KPLED 23 I Drive keypad backlight ANT_BT 53 RF synchronization RF_SYNC Other signal SIM800_Hardware Design_V1.
Smart Machine Smart Decision 3.3. Package Dimensions Figure 3: Dimensions of SIM800 (Unit: mm) SIM800_Hardware Design_V1.
Smart Machine Smart Decision Figure 4: Recommended PCB footprint outline (Unit: mm) SIM800_Hardware Design_V1.
Smart Machine Smart Decision 4. Application Interface 4.1. Power Supply The power supply range of SIM800 is from 3.4V to 4.4V. Recommended voltage is 4.0V. The transmitting burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the VBAT input, a bypass capacitor (low ESR) such as a 100µF is strongly recommended. The 33pF and 10pF capacitors can effectively eliminate the high frequency interference. A 5.
Smart Machine Smart Decision If there is a high drop-out between the input and the desired output (VBAT), a DC-DC power supply will be preferable because of its better efficiency especially with the 2A peak current in burst mode of the module. The following figure is the reference circuit. FB101 is very important, customer can get better EMI feature with appropriate filtering bead. Figure 7: Reference circuit of the DC-DC power supply The single 3.
Smart Machine Smart Decision input voltage never drop below 3.0V even when current consumption rises to 2A in the transmit burst. If the power voltage drops below 3.0V, the module may be shut down automatically. The PCB traces from the VBAT pins to the power supply must be wide enough (at least 60mil) to decrease voltage drops in the transmit burst. The power IC and the bypass capacitor should be placed to the module as close as possible. Figure 9: The minimal VBAT voltage requirement at VBAT drop 4.1.2.
Smart Machine Smart Decision Figure 11: Power on/down module using button The power on timing is illustrated as following figure. Figure 12: Timing of power on module When power on procedure is completed, SIM800 will send following URC to indicate that the module is ready to operate at fixed baud rate. RDY This URC does not appear when autobauding function is active. Note: User can use AT command “AT+IPR=x” to set a fixed baud rate and save the configuration to non-volatile flash memory.
Smart Machine Smart Decision z z Abnormal power down: over-voltage or under-voltage automatic power down. Abnormal power down: over-temperature or under-temperature automatic power down. 4.2.2.1. Power down SIM800 by the PWRKEY Pin User can power down SIM800 by pulling down the PWRKEY pin for at least 1 second and then release. Please refer to the power on circuit. The power down sequence is illustrated in following figure.
Smart Machine Smart Decision 4.2.2.3. Over-voltage or Under-voltage Power down The module software monitors the VBAT voltage constantly. If the voltage ≤ 3.5V, the following URC will be reported: UNDER-VOLTAGE WARNNING If the voltage ≥ 4.3V, the following URC will be reported: OVER-VOLTAGE WARNNING If the voltage < 3.4V, the following URC will be reported, and the module will be automatically powered down. UNDER-VOLTAGE POWER DOWN If the voltage > 4.
Smart Machine Smart Decision Figure 14: Reset circuit The typical value of RESET pin high level is 2.8V, so for the 3V or 3.3V, customer could use MCU’s GPIO to driver this pin directly, resistor in serial the RESET signal could enhance the ESD performance but the value should not be too high, otherwise the level of RESET could be lower than threshold value; RESET hardware parameters can refer to the following table.
Smart Machine Smart Decision 4.3. Power Saving Mode SIM800 has two power saving modes: Minimum function mode and sleep mode. The AT command “AT+CSCLK=1”can be used to set SIM800 into sleep mode. The AT command “AT+CFUN=” can be used to set SIM800 into minimum function. When SIM800 is in sleep mode and minimum function mode, the current of module is the lowest. 4.3.1. Function Mode There are three function modes, which could be set by the AT command “AT+CFUN=”.
Smart Machine Smart Decision 4.4. RTC Backup VRTC is an input pin when the VBAT is not supplied by external power. When the VBAT power supply is in present and the backup battery is in low voltage state, VRTC can charge the backup battery. The RTC power supply of module can be provided by an external capacitor or a battery (non-chargeable or rechargeable) through the VRTC. The following figures show various reference circuits for RTC back up.
Smart Machine Smart Decision 4.5. Serial Port and USB Interface SIM800 provides one unbalanced asynchronous serial port. The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection between module and client (DTE).
Smart Machine Smart Decision Autobauding allows SIM800 to automatically detect the baud rate of the host device. Pay more attention to the following requirements: z Synchronization between DTE and DCE: When DCE powers on with autobauding enabled, firstly, user must send character “A” or “a” to synchronize the baud rate. It is recommended to send “AT” until DTE receives the “OK” response, which means DTE and DCE are correctly synchronized. For more information please refer to the AT command “AT+IPR”.
Smart Machine Smart Decision Figure 20: Level converting by resistor If the voltage of UART is 3V or3.3V, user also can use following reference circuits: Figure 21: Isolation circuit by diodes Note: when a diode used to isolate voltage cross, customer should notice that there’s voltage drop on the diode. And the signal’s voltage level should meet the customer’s electrical character. The recommend diode is Schottky diode e.g. RB551V-30TE-17 and SDM20U40.
Smart Machine Smart Decision VDD_EXT Customer VDD_EXT MCUVDD 4.7K 4.7K Module 47K MCUTXD RXD Figure 23: RX level converting by transistor Note: The recommend Transistors’ part numbers are 2SC4617TLR and PBHV8115Z. when update firmware via the TXD/RXD circuit as figure 22 and figure 23 shows, customer should make sure the VDD_EXT has voltage output, or a external LDO should be added to power VDD_EXT. 4.5.3 USB Interface USB interface supports software debug function.
Smart Machine Smart Decision 4.5.4 Software Upgrade and Debug USB and UART interfaces can be used for firmware upgrade. If customer upgrading firmware via the USB port, SIM800 must be powered first, then connect VBUS, USB_DP, USB_DM and GND to PC. There is no need to operate PWRKEY pin in the whole procedure, when SIM800 detects VBUS and could communicate normally by USB_DP and USB_DM, module will enter USB download mode automatically.
Smart Machine Smart Decision TXD 9 TXD UTXD1(OUT) RXD 10 RXD URXD1(IN) Note: Multiplex Function needs different software version. 4.6. RI Behaviors Table 12: RI Behaviors State RI response Standby High Voice call The pin is changed to low. When any of the following events occur, the pin will be changed to high: (1)Establish the call (2)Hang up the call Data call The pin is changed to low.
Smart Machine Smart Decision Figure 28: RI behaviour of URC or receive SMS However, if the module is used as caller, the RI will remain high. Please refer to the following figure. HIGH LOW RI Idle Ring Establish the call Hang up the call Idle Figure 29: RI behaviour as a caller 4.7. Audio Interfaces SIM800 provides one analog input, which could be used for electret microphone. The module also provides one analog output. The output can directly drive 32Ω receiver.
Smart Machine Smart Decision 4.7.1. Speaker Interfaces Configuration Figure 30: Speaker reference circuit 4.7.2. Microphone Interfaces Configuration Figure 31: Microphone reference circuit SIM800_Hardware Design_V1.
Smart Machine Smart Decision 4.7.3. Audio Electronic Characteristic Table 14: Microphone input characteristics Parameter Min Mic biasing voltage Typ Max Unit 1.9 2.2 V 2 mA 27 KΩ -67 dBm Working Current Input impedance(differential) 13 20 Idle channel noise SINAD Input level:-40dBm0 29 dB Input level:0dBm0 69 dB Table 15: Audio output characteristics parameter Conditions Min Typ Max Unit Normal output RL=32 Ω receiver - 90 - mW 4.7.4.
Smart Machine Smart Decision z z z z z z Fully compliant with Bluetooth specification3.0 + EDR Support operation with GPS and GSM/GPRS worldwide radio systems Fully integrated PA provides 10dbm output power Up to 4 simultaneous active ACL links Support sniff mode Supports PCM interface and built-in programmable transcoders for liner voice with transmission 4.9.
Smart Machine Smart Decision card detection function. For details of this AT command, please refer to document [1]. If the SIM card detection function is not used, user can keep the SIM_PRESENCE pin open. The reference circuit of 6-pin SIM card holder is illustrated in the following figure. Figure 33: Reference circuit of the 6-pin SIM card holder 4.9.2.
Smart Machine Smart Decision Figure 34: Molex 91228 SIM card holder Table 17: Pin description (Molex SIM card holder) Pin name Signal Description C1 VSIM SIM card power supply C2 SIM_RST SIM card reset C3 SIM_CLK SIM card clock C3 GND Connect to GND C5 GND Connect to GND C6 VPP Not connect C7 SIM_DATA SIM card data I/O C8 SIM_PRE Detect SIM card presence For 6-pin SIM card holder, SIMCom recommends to use Amphenol C707 10M006 5122 .User can visit http://www.amphenol.
Smart Machine Smart Decision Figure 35: Amphenol C707 10M006 5122 SIM card holder Table 18: Pin description (Amphenol SIM card holder) Pin name Signal Description C1 VSIM SIM card power supply C2 SIM_RST SIM card reset C3 SIM_CLK SIM card clock C5 GND Connect to GND C6 VPP Not connect C7 SIM_DATA SIM card data I/O 4.10. PCM Interface SIM800 provides PCM interface.
Smart Machine Smart Decision PCM_SYNC 14 PCM synchrony PCM_CLK 68 PCM clock SIM800 PCM interface only supports master mode, data length is 16 bits (linear), and PCM clock rate is 256 KHz.
Smart Machine Smart Decision 4.10.2. PCM Interface Refer to the following figure for PCM design: Figure 36: PCM reference circuit 4.10.3. LCD Display/SPI Interface SIM800 provides a serial interface. It could be used as SPI interface in the embedded AT application. For details about embedded AT application, please refer to document [1].
Smart Machine Smart Decision 4.10.4. SD Card Interface DAT2 DAT3 MC3DA2 MC3DA3 MC3CM0 VDD_EXT MC3CK VSS MC3DA0 MC3DA1 CMD VDD CLK VSS DAT0 DAT1 SD card Module Figure 38: SD reference circuit If the VDD of SD card is 2.8V, user can use VDD_EXT power the SD card directly. If the VDD is 3.3V, customer should design the power circuit external. 4.11.
Smart Machine Smart Decision Module supports a new keypad connection, it can support 5*5*2 amount 50 keypads, meet full keyboard demand, and the connection diagram is as follow: Figure 40: Extended keypad reference circuit Note: Do not change the 20KΩ resistor in the diagram. Customer should add a resistor to enhance the ESD performance and the value of resistor should be less than 1KΩ, the connection diagram is shown in figure 41 as an example.
Smart Machine Smart Decision Figure 42: Keypad detected Table 22: Pin definition of the keypad interface Name Pin Function Default state COL0 51 Pull up COL1 50 Pull down COL2 49 COL3 48 Pull down COL4 47 Pull down ROW0 44 Pull down ROW1 43 Pull down ROW2 42 ROW3 41 Pull down ROW4 40 Pull down Keypad matrix column Keypad matrix row Pull down Pull down Table 23: Keypad multiplex function Pin name Pin number Mode 0(default) Mode 1 COL0 51 COL0 GPIO10 COL1 50 COL
Smart Machine Smart Decision 4.12. I2C BUS The SIM800 provides an I2C interface, it can be driven by either the master or slave and conform to the I2C specification.
Smart Machine Smart Decision 4.14. ADC Table 27: Pin definition of the ADC Pin name Pin number Description ADC 25 Analog to Digital Converter SIM800 provides an auxiliary ADC, which can be used to measure the voltage. User can use AT command “AT+CADC” to read the voltage value. For details of this AT command, please refer to document [1]. Table 28: ADC specification Parameter Min Typ Max Unit Voltage range 0 - 2.8 V ADC Resolution - 10 - bits Sampling rate - - 1.
Smart Machine Smart Decision VBAT PWM 4.7K 47K Figure 43: Reference circuit of PWM drive buzzer Table 30: Buzzer output characteristics Parameter Min Typ Max Unit Working voltage 2.5 2.8 2.9 V 16 mA Working current Note: PWM pin must keep low when module in the boot process. Table 31: PWM multiplex function Pin name Pin number Mode 0(default) Mode 1 PWM1/GPIO22 35 PWM1 GPIO22 PWM2/GPIO23 36 GPIO23 PWM2 4.16.
Smart Machine Smart Decision Figure 44: Reference circuit of NETLIGHT 4.17. Operating Status Indication The STATUS pin indicates the operating status of module. The pin output high when module power on, output is low when module powered off. Table 34: Pin definition of the STATUS Pin name Pin number Description STATUS 66 Operating status indication 4.18. KPLED SIM800 provides one open-drain LED driver pin.
Smart Machine Smart Decision Table 36: KPLED specification Pin name Min Typ Max Unit KPLED 60 - 100 mA 4.19. RF Synchronization Signal The synchronization signal serves to indicate growing power consumption during the transmit burst. Table 37: Definition of the RF_SYNC pin Pin name Pin number Description RF_SYNC 67 Transmit synchronization signal Note: Do not pull up RF_SYNC. The timing of the synchronization signal is shown in the following figure.
Smart Machine Smart Decision 4.20.1. GSM Antenna Interface There is a GSM antenna pad named RF_ANT to connect an external GSM antenna, the connection of the antenna must be decoupled from DC voltage. This is necessary because the antenna connector is DC coupled to ground via an inductor for ESD protection.
Smart Machine Smart Decision Figure 49: Bluetooth antenna matching circuit R201, C201, C202 are the matching circuit, the values depend on antenna debug result. Normally R201 is 0Ω, C201 and C202 are not mounted. SIM800_Hardware Design_V1.
Smart Machine Smart Decision 5. PCB Layout Usually, most electronic products with good performance are based on good PCB layout. Poor PCB layout will lead to lots of issues, like TDD noise, SIM card undetected, etc. The final solution for these problems is to redo PCB layout. Making good PCB layout will save developing schedule and cost as well. This section will give some guidelines on PCB layout, in order to eliminate interfere or noise by greatest degree, and save product development period. 5.
Smart Machine Smart Decision 5.2.4 Audio Interface In order to avoid TDD noise, or current noise, or some other noise, the signal trace of audio should far away from antenna and power, and it is recommended to surround audio traces by ground. And do not rout audio trace and VBAT trace parallel. 5.2.5 Others It’s better to trace signal lines of UART bunched, as well as signals of USB and LCM. SIM800_Hardware Design_V1.
Smart Machine Smart Decision 6. Electrical, Reliability and Radio Characteristics 6.1 Absolute Maximum Ratings The absolute maximum ratings stated in following table are stress ratings under non-operating conditions. Stresses beyond any of these limits will cause permanent damage to SIM800. Table 38: Absolute maximum ratings Symbol Min Typ Max Unit VBAT - - 4.5 V Peak Current 0 - 2.
Smart Machine Smart Decision 6.4 SIM Card Interface Characteristics Table 41: SIM card interface characteristic Symbol Parameter Min Typ Max Unit IIH High-level input current -1 - 1 uA IIL Low-level input current -1 - 1 uA VIH High-level input voltage 1.4 - - V 2.4 - - V VIL Low-level input voltage - - 0.27 V 0.4 V VOH High-level output voltage VOL Low-level output voltage 6.5 1.62 - - V 2.7 - - V - - 0.36 V - - 0.
Smart Machine Smart Decision 6.8 Current Consumption (VBAT=4V) Table 45: Current consumption Symbol Parameter VBAT Voltage IVBAT IMAX Conditions Min Typ Max Unit 3.4 4.0 4.4 V Power drop PCL=5 350 mV Voltage ripple PCL=5 @ f<200kHz @ f>200kHz 50 2 mV mV 60 uA Average current Peak current Power down mode 50 Sleep mode (AT+CFUN=1): ( BS-PA-MFRMS=9 ) ( BS-PA-MFRMS=5) ( BS-PA-MFRMS=2) 1.171 1.307 2.046 mA mA mA Idle mode (AT+CFUN=1): EGSM900 22.
Smart Machine Smart Decision 6.9 Electro-Static Discharge SIM800 is an ESD sensitive component, so more attention should be paid to the procedure of handling and packaging. The ESD test results are shown in the following table. Table 46: The ESD characteristics (Temperature: 25°C, Humidity: 45 %) Pin Contact discharge Air discharge VBAT ±5KV ±10KV GND ±5KV ±10KV RXD, TXD ±4KV ±8KV Antenna port ±5KV ±10KV SPK_P/SPK_N/MIC_P/MIC_N ±4KV ±8KV PWRKEY ±4KV ±8KV 6.
Smart Machine Smart Decision Table 48: DCS 1800 and PCS 1900 conducted RF output power DCS1800,PCS1900 PCL Nominal output power (dBm) 0 Tolerance (dB) for conditions Normal Extreme 30 ±2 ±2.5 1 28 ±3 ±4 2 26 ±3 ±4 3 24 ±3 ±4 4 22 ±3 ±4 5 20 ±3 ±4 6 18 ±3 ±4 7 16 ±3 ±4 8 14 ±3 ±4 9 12 ±4 ±5 10 10 ±4 ±5 11 8 ±4 ±5 12 6 ±4 ±5 13 4 ±4 ±5 14 2 ±5 ±6 15 0 ±5 ±6 6.
Smart Machine Smart Decision 7. Manufacturing 7.1. Top and Bottom View of SIM800 Figure 50: Top and Bottom View of SIM800 7.2. Typical Solder Reflow Profile Figure 51: Typical Solder Reflow Profile Note: Please refer to《Module secondary-SMT-UGD》 for more information about the module shipping and manufacturing. SIM800_Hardware Design_V1.
Smart Machine Smart Decision 7.3. The Moisture Sensitivity Level The moisture sensitivity level of SIM800 is 3. The module should be mounted within 168 hours after unpacking in the environmental conditions of temperature <30°C and relative humidity of <60% (RH).
Smart Machine Smart Decision 8. Appendix I. Related Documents Table 53: Related Documents SN Document name [1] SIM800 Series_AT Command Manual_V1.00.doc [2] ITU-T Draft recommendation V.25ter: [3] GSM 07.07: Digital cellular telecommunications (Phase 2+); AT command set for GSM Mobile Equipment (ME) [4] GSM 07.10: Support GSM 07.10 multiplexing protocol GSM 07.
Smart Machine Smart Decision II.
Smart Machine Smart Decision III.
Smart Machine Smart Decision TE Terminal Equipment, also referred to as DTE TX Transmit Direction UART Universal Asynchronous Receiver & Transmitter URC Unsolicited Result Code USSD Unstructured Supplementary Service Data VSWR Voltage Standing Wave Ratio Phonebook abbreviations FD SIM fix dialing phonebook LD SIM last dialing phonebook (list of numbers most recently dialed) MC Mobile Equipment list of unanswered MT calls (missed calls) ON SIM (or ME) own numbers (MSISDNs) list RC Mobil
Smart Machine Smart Decision IV. Safety Caution Table 56: Safety caution Marks Requirements When in a hospital or other health care facility, observe the restrictions about the use of mobiles. Switch the cellular terminal or mobile off, medical equipment may be sensitive to not operate normally for RF energy interference. Switch off the cellular terminal or mobile before boarding an aircraft. Make sure it is switched off.
Smart Machine Smart Decision Contact us: Shanghai SIMCom Wireless Solutions Ltd. Add: SIM Technology Building,No.633,Jinzhong Road,Changning District,Shanghai P.R. China 200335 Tel: +86 21 3235 3300 Fax: +86 21 3235 3301 URL: www.sim.com/wm SIM800_Hardware Design_V1.
