Owner's manual

ManualsBrandsNortel Networks ManualsVideo surveillance systems1000

141

142

143

144

145

146

147

148

149

150

146 NT1R20 Off-Premise Station Analog Line card

For satisfactory transmission performance, particularly on connections

between the public network and an OPS termination, it is recommended

that facilities conform to the following:

• Total 1 kHz loss from the local serving CO to the OPS terminal

should not exceed 7.0 dB. The total loss in the facility between

the PBX and the terminal must not exceed 4.5 dB. See Figure 90

"NTCK80AA/AB/AC/AD" (page 332). The following requirements are

based on historic inserted connection loss (ICL) objectives:

—

PBX – CO trunk: 5 dB with gain; 0 – 4.0 dB without gain

— OPS line: 4.0 dB with gain; 0 – 4.5 dB without gain Economic and

technological changes led to modifications of these objectives. But

since the loss provisions in the PBX for OPS are constrained by

regulatory requirements as well as industry standards, they are not

designed to compensate for modified ICL designs in the connecting

facilities.

•

Nortel Networks recommends that the attenuation distortion (frequency

response) of the OPS facility be within ±3.0 dB over the frequency

range from 300 to 3000 Hz. It is desirable that this bandwidth extend

from 200 to 3200 Hz.

• The terminating impedance of the facility at the OPS port be

approximately that of 600 ohms cable.

If the OPS line facility loss is greater than 4.5 dB but does not exceed 15

dB, line treatment using a switched-gain Voice Frequency Repeater (VFR)

extends the voice range.

The overall range achievable on an OPS line facility is limited by the

signaling range (2300 ohms loop including telephone set resistance). The

signaling range is unaffected by gain treatment; so gain treatment can

be used to extend the voice range to the limit of the signaling range. For

example, on 26 AWG wire, the signaling range of 2300 ohms corresponds

to an untreated metallic loop loss of 15 dB. Gain treatment (such as a

VFR) with 10.5 dB of gain would maintain the OPS service loss objective

of 4.5 dB while extending the voice range to the full limit of the signaling

range.

15 dB

–4.5 dB

= 10.5

The use of dial long line units to extend signaling range of OPS analog line

cards beyond 15 dB is not recommended.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 02.06 Standard

27 August 2008