Page396 of 544 NT8D15E&M TrunkCard
553-3011-100 Standard14.00 January 2002
Release Control
Release control of a call made over a trunk is specified in the route data block
(LD 16). Disconnect supervision is specified for each trunk group
independently.
Only incoming trunks in idle ground start configuration can provide
disconnect supervision. For a list of prompts and responses and default
conditions see the Administration (553-3001-311).
PAD Switching
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
2dB 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.
In Option 11C systems, Table120 on page 397 shows the insertion loss from
IPE port to IPE port.