Nortel Networks 311

158 NT1R20 Off-Premise Station Analog Line card

•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 or a keytelephone 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 used in an OPS

arrangement without consideration for these characteristics, the result could

be a signiﬁcant deviation from optimum loudness performanceThe 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;

that at the OPS termination end depends on the OPS termination

receive loudness characteristics. With standard telephone sets, these

characteristics are such that satisfactory—if not optimum—performance is

achievablewithin the above noted objectives for connecting facilities.

A feature of many (though not all) standard telephone sets is that the

loudness increases with decreased current. So as the line (Meridian 1 to

OPS termination) facility gets longer and loss increases, the increased

loudness of the set somewhat compensates forthe 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 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 deployedin 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.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 01.04 Standard

Release 5.0 23 May 2008