Nortel Networks 1000 - Manual (Page 148)

148 NT1R20 Off-Premise Station Analog Line card
•
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 may 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 be a significant deviation from optimum loudness performance.
The loss plan for OPS connections is designed so that a connection with
an OPS termination provides satisfactory end-to-end listener volume
when the OPS termination is a standard telephone. 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.
A feature of many (though not all) standard telephones is that the loudness
increases with decreased current. So as the line (Meridian 1 to OPS
termination) facility gets longer and lossier, the increased loudness of the
telephone somewhat compensates for the higher loss, assuming direct
current feed from the PBX with constant voltage at the feeding bridge.
However, this compensation is not available when:
• the termination is a non-compensating telephone
•
the OPS port is served by a line card using a constant-current feeding
bridge
•
the OPS termination is to telephones behind a local switch providing
local current feed, such as a fax machine
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 used in an
OPS arrangement without consideration for these characteristics, the result
could be a significant deviation from optimum loudness performance.
The loss plan for OPS connections is designed so that a connection with
an OPS termination provides 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.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.