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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127
Issue 1
August 1997
Maintenance Object Repair Procedures
Page 10-155BRI-PORT (ISDN-BRI Port), ABRI-PORT (ASAI ISDN-BRI Port)
10
!
WARNING:
If a significant Packet Bus failure occurs, errors and alarms may not be
logged as expected for
BRI-PORT/ABRI-PORT/ATT-PORT/LGATE-PT/ATTE-PT. Conditions under
which this occurs are detailed in the "Maintenance of the Packet Bus"
section of Chapter 9, "Packet Bus Fault Isolation and Correction".
The TN2208 LGATE MFB provides DEFINITY with the interface to Adjunct-Switch
Application Interface (ASAI) and AT&T adjuncts (for example, CONVERSANT
®
.
Voice System). The circuit pack contains 12 ports of line circuit interface
(although only 8 are usable by the switch), each of which operates with two
B-channels (referred to as B1 and B2 throughout this section) and one D-channel
as specified in the AT&T ISDN-BRI Specification. In this context, the term
"ISDN-BRI port" is used to refer collectively to ports on the TN2208 circuit pack
which are connected to ASAI or AT&T adjuncts.
The TN556 and TN2198 ISDN-BRI Line circuit packs provide DEFINITY with the
interface to ISDN-BRI end points, Adjunct-Switch Application Interface (ASAI)
and AT&T adjuncts (for example, CONVERSANT®. Voice System). The circuit
packs contain 12 ports of line circuit interface, each of which operates with two
B-channels (referred to as B1 and B2 throughout this section) and one D-channel
as specified in the AT&T ISDN-BRI Specification. In this context, the term
"ISDN-BRI port" is used to refer collectively to ports on the TN556 an TN2198
circuit packs which are connected to either BRI endpoints or ASAI or AT&T
adjuncts.
For BRI endpoints, each B-channel may support voice or circuit-switched data
and may be circuit-switched simultaneously. The B-channels are not used on
ports connected to ASAI or AT&T adjuncts. The D-channel is used for conveying
signaling between the switch and a BRI endpoint(s) or ASAI or AT&T adjunct.
Each ISDN-BRI D-channel is connected to the switch processor and the
ISDN-BRI port through the Packet Control circuit pack and the Packet Bus.
ISDN-BRI endpoints are available in various configurations. All endpoints require
the D-channel to convey signaling information to the switch. Only one B-channel
is required for a voice-only set or a stand-alone data module (BRI-DAT). A voice
and data-capable set requires both B-channels (one for voice and one for data).
Therefore, each TN556 or TN2198 port can support either two voice-only sets,
two stand-alone data modules (BRI-DAT), or one voice and data-capable set.
Only a single ASAI or AT&T adjunct may be connected to an ISDN-BRI port.
Multiple adjuncts per line are not supported.
Figure 10-6 illustrates the physical connection (solid line) between an ISDN-BRI
Port and its associated ISDN-BRI set(s). Each physical connection allows for two
B-channels and one D-channel. Each ISDN-BRI circuit pack can support up to
12 of these
physical
connections to different voice and voice/data sets or ASAI or
AT&T adjuncts. On a TN2198 each ISDN-BRI circuit pack can support up to 12
physical
connections to a NT1, which, in turn, connects to 2 terminals.