Demand test descriptions and error codes - Avaya Support

The TN2208 LGATE MFB provides Communication Manager with the interface to
Adjunct-Switch Application Interface (ASAI) and Avaya 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-Chels (referred to as B1 and B2
throughout this section) and one D-Chel. In this context, the term “ISDN-BRI port” is used to
refer collectively to ports on the TN2208 circuit pack that are connected to ASAI or Avaya
adjuncts.
The TN556 and TN2198 ISDN-BRI Line circuit packs provide the system with the interface to
ISDN-BRI endpoints, Adjunct-Switch Application Interface (ASAI) and Avaya adjuncts (for
example, CONVERSANT® Voice System). The circuit packs contain 12 ports of line circuit
interface, each of which operates with two B-Chels (referred to as B1 and B2 throughout this
section) and one D-Chel. In this context, the term “ISDN-BRI port” is used to refer collectively to
ports on the TN556 and TN2198 circuit packs that are connected to either BRI endpoints, ASAI
or Avaya adjuncts.
The MM720 BRI Media Module provides 8 S/T ISDN 2B+D ports that interface to either the
central office or another PBX. The MM720 contains eight, 4-wire ports that interface to the
network at the ISDN S/T reference point over two 64 Kb chels (B1 and B2) and over a 16Kb
signaling (D) chel. The B1 and B2 chels can be simultaneously circuit switched, or individually
packet switched. The D-chel is circuit switched. The circuit-switched connections have a
Mu-law or A-law option for voice and operate as 64Kb clear data chels.
Note:
Note: This maintenance object applies to the MM720 BRI Media Module only if its ports
are all configured as station line ports instead of trunk ports.
For BRI endpoints, each B-Chel may support voice or circuit-switched data and may be
circuit-switched simultaneously. The B-Chels are not used on ports connected to ASAI or Avaya
adjuncts. The D-Chel is used for conveying signaling between the switch and a BRI endpoint(s),
ASAI or Avaya adjunct. Each ISDN-BRI D-Chel is connected to the switch processor and the
ISDN-BRI port through the packet bus.
ISDN-BRI endpoints are available in various configurations. Every endpoint requires the D-Chel
to convey signaling information to the switch. Only one B-Chel is required for a voice-only set or
a stand-alone data module (BRI-DAT). A voice and data-capable set requires both B-Chels (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 Avaya adjunct may be connected to an ISDN-BRI port. Multiple adjuncts
per line are not supported.
Figure 4: ISDN-BRI Port Interactions 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-Chels and one D-Chel. Each ISDN-BRI circuit pack can support up to 12 of these physical
connections to different voice and voice/data sets or ASAI or Avaya 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.
216 Maintenance Alarms for Communication Manager, Media Gateways and Servers