Nortel Networks 1000 User Manual

Page 715

Applications

715

Table 283
Insertion Loss from IPE Ports to IPE Ports (measured in dB) (cont’d.)

The transmission properties of each trunk are characterized by
class-of-service (COS) assignments in the trunk data block (LD 14). The
assignment may be non-Via Net Loss (non-VNL) or via Net Loss (VNL). To
ensure stability and minimize echo when connecting to long-haul VNL (Tie)
trunks, non-VNL trunks are assigned either Transmission Compensated
(TRC) or Non-Transmission Compensated (NTC) class-of-service.

The TRC and NTC COS options determine the operation of the switchable
pads contained in the trunk circuits. They are assigned as follows:

•

TRC for a two-wire non-VNL trunk facility with a loss of greater than 2
dB or for which impedance compensation is provided, or for a four-wire
non-VNL facility.

•

NTC for a two-wire non-VNL trunk facility with a loss of less than 2 dB
or when impedance compensation is not provided.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311

02.06

Standard

27 August 2008