Nortel Networks 1000 - Manual (Page 149)

Application 149
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 in the following
situations:
•
when the termination is a non-compensating telephone set
• when the OPS port is served by a line card using a constant-current
feeding bridge
• when 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.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
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