Nortel Networks 1000 User Manual
Page 625
Configuration
625
The VNL class of service is assigned at the prompt CLS with the response
VNL. The non-VNL class of service is assigned at prompt CLS by selecting
either the Transmission Compensated (TRC) or Non-Transmission
Compensated (NTC) response.
Non-VNL trunks are assigned a TRC or NTC class of service to ensure
stability and minimize echo when connecting to long-haul trunks, such as
TIE trunks. The class of service determines the operation of the switchable
pads contained in each unit. They are assigned as follows:
•
TRC for a 2-wire non-VNL trunk facility with a loss of greater than 2
dB, or for which impedance compensation is provided, or for a 4-wire
non-VNL facility
•
NTC for a 2-wire, non-VNL trunk facility with a loss of less than 2 dB,
or when impedance compensation is not provided
See
Table 238 "Pad switching algorithm" (page 625)
for the pad switching
control for the various through connections and the actual port-to-port loss
introduced for connections between the Universal trunk card and any other
IPE or PE port designated as Port B.
Table 238
Pad switching algorithm
Port B pads
Universal Trunk
Pads
Port-to-port loss (dB)
Port B
Transmit
D to A
Receive
A to D
Transmi
D to A
Receive
A to D
Port B to
Universal
trunk
card
Universal
trunk
card to
Port B
IPE line
N/A
N/A
Out
Out
0.5
0.5
Universal trunk (TRC)
In
Out
In
Out
1
1
IPE TIE (VNL)
In
In
Out
Out
0
0
PE line
N/A
N/A
Out
Out
1
1
Note 1: Transmit and receive designations are from and to the Meridian 1. Transmit is from the
Meridian 1 to the external facility (digital-to-analog direction in the Universal trunk card). Receive is
to the Meridian 1 from the external facility (analog-to-digital direction in the Universal
Note 2: When Port B is the call originating port. If the Universal trunk card is the originating port, the
UTC pads are out, the Port B (PE CO/FX/WATS) pads are in.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
02.06
Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.