Nortel Communication Server 1000S Installation And Configuration Manual page 251

NTAK93 D-channel Handler Interface (DCHI) daughterboard
The NTAK93 DCHI daughterboard interfaces with the system Central
Processing Unit (CPU) and mounts on the NTAK09 DTI/PRI circuit card for
PRI or ISL shared mode applications. The DCHI is responsible for
performing the Q.921 layer 2 protocol information. It transfers layer 3
signaling information between two adjacent network switches.
The NTAK93 DCH daughterboard, when installed on the NTAK09 circuit
card, is addressed in the same slot as the NTAK09. The NTAK93 can use SDI
I/O addresses 0 to 79 and port 1.
Note: I/O addresses 0, 1, 2, 8 and 9 are preconfigured on the Small
System and must not conflict with the I/O addresses on the NTAK93
card.
A minimum of one NTAK93 is required for each PRI link. If more than one
PRI link connects to the same end location, a single DCHI circuit card can
support up to a maximum of sixteen PRI connections for the Small System
and CS 1000S system. This allows a total of 382 B-channels or PRI trunks to
be supported if a backup D-channel is also used. A total of 383 B-channels or
PRI trunks are supported if a backup channel is not used.
NTBK51BA Downloadable D-channel (DDCH) daughterboard
The NTBK51BA DDCH daughterboard interfaces with the Small System
Central Processing Unit (CPU) and mounts on the NTAK09 DTI/PRI circuit
card for PRI D-channel applications. The DDCH is equivalent to the MSDL
card used on a Large System, but it only supports D-channel applications (no
SDI or ESDI).
The NTBK51BA DDCH daughterboard, when installed on the NTAK09
circuit card, is addressed in the same slot as the NTAK09.
A minimum of one NTBK51BA is required for each PRI link. If more than
one PRI link connects to the same end location, a single DDCH circuit card
can support up to a maximum of sixteen PRI connections for the Small
Systems and CS 1000S systems. This allows a total of 382 B-channels or PRI
trunks to be supported if a backup D-channel is also used. A total of 383
B-channels or PRI trunks are supported if a backup channel is not used.
1.5 Mb PRI implementation
ISDN Primary Rate Interface
Page 251 of 394
Installation and Configuration