Nortel Networks Circuit Card 311 User Manual
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NT1R20 Off-Premise Station Analog Line card
•
The attenuation distortion (frequency response) of the OPS facility
should 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 should
approximate that of 600 ohm 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 ohm loop including telephone set 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 voice range to the full limit of the signaling range:
•
15 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 signaling range of OPS analog line
cards beyond 15 dB is not recommended.
Loss is inserted between OPS analog line card ports and other ports in
accordance with the loss plan. This plan determines the port-to-port loss
for each call. 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:
•
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
. 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
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
01.04
Standard
Release 5.0
23 May 2008
Copyright © 2003-2008, Nortel Networks
.