Demand test descriptions and error codes - Avaya Support

On 24-chel interfaces, any of the first 23 ports on the DS1 circuit packs or media modules can
be a B-Chel. On the TN464C or higher suffix UDS1 circuit pack or DS1 Media Module, the 24 th
port may be used as a B-Chel or as a D-Chel depending on the type of ISDN-PRI signaling
group (FAS or NFAS) implemented on the circuit pack or media module. For more details, see
ISDN-SGR (ISDN-PRI Signaling Group). On the TN767 DS1 circuit pack, all 24 ports are used
as B-Chels since D-chel signaling is not supported on the TN767 circuit pack. The signaling for
these B-Chels is done over a D-Chel located on a UDS1 TN464C or higher suffix board.
On 32-chel interfaces, any of ports 1 – 15 and 17 – 31 on the DS1 interface circuit pack or
media module can be a B-Chel. The 16th port may be used as a B-Chel or as a D-Chel
depending on the type of ISDN-PRI signaling group (FAS or NFAS) to which it belongs. For
more details, see ISDN-SGR (ISDN-PRI Signaling Group) and DS1-BD (DS1 Interface Circuit
Pack) or MG-DS1 (DS1 Interface Media Module).
For interfaces using country protocol 1 on the DS1 circuit pack or media module administration
form (including US), the signaling protocol used for the maintenance of the B-Chel is defined by
the Avaya ISDN-PRI specification. For interfaces using country protocols other than 1, the
signaling protocol used for the maintenance of the B-Chel is defined by the CCITT ISDN-PRI
Specification.
There are five possible service states for a B-Chel. The service state is negotiated with the
far-end switch, changes over time, and may have far-end and near-end components. The
service state is initialized to Out-of-Service/Far-End, and an attempt is made to negotiate it to
In-Service.
Note: The
Note:
service state of a particular DS1 ISDN Trunk B-Chel can be displayed by
entering status trunk grp#/mem# on the system access terminal.
When a call is present, the specification defines the permissible call states, as well. There are
tests in the short and long test sequences for DS1 ISDN Trunk designed to audit these states
and ensure agreement between both ends of the PRI connection.
558 Maintenance Alarms for Communication Manager, Media Gateways and Servers