Nortel Networks 311

Application 155

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 ohm loop including telephone resistance). 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 voicerange to the full limit of the signaling range:

15.0 dB (loss corresponding to the maximum signaling range)

–4.5 dB (OPS service loss objective)

=10.5 dB (required gain treatment)

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

line cards beyond 15 dB is not recommended.

Loss is inserted between OPS analog line card ports and other Meridian

1 ports in accordance with the Meridian 1 loss plan. This plan determines

the port-to-port loss for each call. When a port is conﬁgured for OPS

class-of-service, loss is programmed into the OPS analog line card on a

call-by-call basis. When conﬁgured for ONS class-of-service, an OPS

analog line card port is programmed to a value that is ﬁxed forall calls,

although the loss in the other port involved in the call may vary on a

call-by-call basis to achievethe 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.Of that total, the loss in the facility between the PBX

and the terminal should not exceed 4.5 dB (see "QPC430 and QPC723

interfaces" (page 472)).

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 consideration has

led to modiﬁcations of these historic objectives. However, the

loss provisions in the PBX for OPS are constrained by regulatory

requirements as wellas industr y standards; so, theyare not designed

to compensate for modiﬁed ICL designs in the connecting facilities.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 01.04 Standard

Release 5.0 23 May 2008