Nortel Networks 553-3001-211 manual 652 of 894 NT8D15 E&M Trunk card

Page 652 of 894 NT8D15 E&M Trunk card

Applications

The optional applications, features and signaling arrangements for each trunk are assigned through unique route and trunk data blocks. Refer to the Features and Services (553-3001-306) for information about assigning features and services to trunks.

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 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.

553-3001-211 Standard 2.00 September 2004