Nortel Networks 311

Application 153

When a port is conﬁgured for CLS OPS, loss is programmed into the OPS

analog line card on a call-by-call basis. When conﬁgured for CLS ONS, an

OPS analog line card port is programmed to a value that is ﬁxed for all calls.

The loss in the other port involved in the call can vary on a call-by-call basis

to achieve the total loss scheduled by the plan.

For satisfactory transmission performance, particularly on connections

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

that facilities conform to the following:

•Total1 kHz loss from the local ser ving 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 25 "TraditionalOPS

application conﬁguration" (page 149).

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. In recent times

economic and technological considerations led to modiﬁcations of

these historic 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 recommends that the attenuation distortion (frequency response)

of the OPS facility be within ±3.0 dB overthe 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 VoiceFrequency Repeater (VFR)

extends the voice range.

The overall range achievableon an OPS line facility is limited by the

signaling range (2300 ohms loop including telephone 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 AWGwire, 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 voicerange to the full limit of the signaling range.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 01.04 Standard

Release 5.0 23 May 2008