Meridian Nortel 1 Option 11C Technical Reference Manual page 435

NT1R20 Off Premise Station (OPS) analog line card
Port-to-port loss
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 for all calls, although the loss in
the other port involved in the call may 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. Of that total, the loss in the facility between the PBX
and the terminal should not exceed 4.5 dB (see Figure 56).
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 well as industry standards; thus, they are not
designed to compensate for modified ICL designs in the connecting
facilities.
• 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) will
extend the voice range.
Option 11C and 11C Mini
Page 435 of 544
Technical Reference Guide