D-Channel Interface - Nortel Enterprise 1000 Reference Manual

Page 202 of 236
Table 53
Digital pad values and offset allocations (Part 2 of 2)
Offset
C
D
E
F

D-channel interface

553-3023-211 Standard 1.00 June 2001
NTRB21 DTI/PRI/DCH TMDI card
The D-channel interface is a 64 kbps, full-duplex, serial bit-stream configured
as a Data Circuit-terminating Equipment (DCE) device. The data signals
include:
• receive data output
• transmit data input
• 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
PAD set 0
1dB
–2dB
–5db
–6db
PAD set 1
spare
spare
spare
spare