Nortel Networks 553-3001-211 manual NTRB21 DTI/PRI/DCH Tmdi card Page 823

NTRB21 DTI/PRI/DCH TMDI card Page 823 of 894

•receive clock output

•transmit clock output

The bit rate of the receive and transmit clocks can vary slightly from each other. This is determined by the transmit and receive carrier clocks.

Feature selection through software configuration for the D-channel includes:

•56 kbps

•64 kbps clear

•64 kbps inverted (64 Kbps restricted)

DCHI can be enabled and disabled independent of the PRI card, as long as the PRI card is inserted in its cabinet slot. The D-channel data link cannot be established unless the PRI loop is enabled.

On the NTRB21 use switch 1, position 1 to select either the D-channel feature or the DPNSS feature, as follows:

OFF = D-channel

The ON setting for DPNSS (U.K.) is not supported at this time.

DS-1 Carrier interface

Transmitter

The transmitter takes the binary data (dual unipolar) from the PCM transceiver and produces bipolar pulses for transmission to the external digital facility. The Digital Signal – Level 1 (DS-1) transmit equalizer enables the cabling distance to be extended from the card to the Digital Signal

Circuit Card Description and Installation