794 NT8D15 E and M Trunkcard
•Port-to-port connection loss is automatically set by software on the basis
of the port type selected in LD 16; only the port type is set by the user.
The transmission properties of each trunk are characterized by the class of
service assigned in LD 14. Transmission properties can be Via Net Loss
(VNL) or non-Via Net Loss (non-VNL).
The VNL class of service is assigned at the CLS prompt by typing VNL. The
non-VNL class of service is assigned at the CLS prompt by typing TRC
(TransmissionCompensated) or NTC (Non-Transmission Compensated).
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 fora 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 Table307 "Pad switching algorithm" (page 792) for the pad switching
control for the various through connections and the actual port-to-port
loss introduced for connections between the E and M Trunkcard and any
other IPE port designated as Port B. Figure 258 "Pad orientation" (page
795) shows the pad switching orientation.
Table308
Pad switching algorithm
Port B pads E and M Trunk Pads Port-to-port loss (dB)
Port B Transmit
DtoA Receive
AtoD Transmit
DtoA Receive
AtoD Port B to
E and M E and M to
Port B
IPE line N/A N/A Out In 2.5 3.5
Universal
trunk (TRC) Out Out In In 00
IPE tie (VNL) In Out In Out 00
PE line N/A N/A Out In 3.0 4.0
Note: Transmit and receive designations are from and to the CS 1000. Transmit is from the CS
1000 to the external facility (digital-to-analog direction in the E and M Trunk card). Receive is to the
CS 1000 from the external facility (analog-to-digital direction in the E and M Trunk card).
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright© 2003-2008, Nor tel Networks
.