Nortel Enterprise 1000 Reference Manual page 225

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.
The use of dial long line units to extend signaling range of OPS analog line
cards beyond 15 dB is not recommended.
Termination transmission characteristics
The loss plan for OPS connections is designed so that a connection with an
OPS termination will provide satisfactory end-to-end listener volume when
the OPS termination is a standard telephone set. The listener volume at the
distant end depends on the OPS termination transmit loudness characteristics;
the volume at the OPS termination end depends on the OPS termination
receive loudness characteristics.
On some standard telephone sets, the loudness increases with decreased
current. As the line (PBX to OPS termination) facility gets longer and loss
increases, the increased loudness of the set compensates for the higher loss,
assuming direct current feed from the PBX with constant voltage at the
feeding bridge. This compensation is not available when:
• the termination is a non-compensating telephone set
• the OPS port is served by a line card using a constant-current feeding
bridge
• the OPS termination is to telephone sets behind a local switch providing
local current feed, such as a key telephone system
OPS line terminations with loudness characteristics designed for other
applications can also impact transmission performance. For example,
wireless portables loudness characteristics are selected for connections to
switching systems for wireless communication systems; if deployed in an
OPS arrangement without due consideration for these characteristics, the
result could deviate significantly from optimum loudness performance.
Succession Communication Server for Enterprise 1000 Circuit Card Reference Guide
Analog line cards
15 dB
– 4.5 dB
= 10.5 dB
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