MERLIN LEGEND Communications System Release 5.0
Feature Reference
555-650-110
Issue 1
June 1997
Features
Page 84
Basic Rate Interface (BRI)
Terminology
3
Lines/Trunks
3
In this section on BRI,
lines
are the representations that appear on extensions or
are put into pools.
Trunks
are the facilities that link switches. For all trunks except
DS1 (T1 or PRI) and BRI, inside line numbers have a one-to-one correspondence
to line/trunk jacks. Because there are two transmission channels, or bearer
channels (called
B-channels
), for each BRI connection, two inside line numbers
are assigned for each BRI port. B-channels are present for each Digital
Subscriber Line (DSL); therefore 16 inside lines are assigned for each module
used.
A B-channel is used to carry user information, such as the voice or data content of
a call, between the system and the far-end switch.
Digital Subscriber Line (DSL)
3
Digital Subscriber Line (DSL)
is used to refer to the facility from the central office
that supports BRI service. A Digital Subscriber Line provides full-duplex service
on a single twisted-pair wire (2-wire) at a rate sufficient to support ISDN Basic
Rate Access.
Directory Number (DN)
3
In general, the
Directory Number
is the telephone number that is dialed to reach a
destination. When an incoming call arrives on a BRI line, the central office
presents the Directory Number as the Called Party Number. Only one call to a
particular Directory Number is accepted at any one time. The Directory Number is
usually a subset of the Service Profile Identifier The DNs for each BRI are still
subsets of the SPIDs. Only the DN for the hunt group are unrelated to the SPIDs.
ISDN Ordering Code (IOC))
3
The
ISDN Ordering Code (IOC)
is defined by Bellcore as part of the National
ISDN Package. The IOC defines a number of capabilities for the BRI connection,
which are aimed at different user applications. The MERLIN LEGEND
Communications System supports the IOC capability package S. IOC package S
supports circuit-switched voice and data calls over both B-channels with a Calling
Party Number identifier.
Multiline Hunt Group
3
A multiline hunt group can be programmed at the central office to send calls to a
number of separate Directory Numbers (DNs) that are grouped together.
A multiline hunt group consists of a group of BRI lines with one main telephone
number (Directory Number). When this number is dialed by an outside caller, the
CO tries to deliver the call to one of the BRI lines in the hunt group. If the BRI line
is busy, the central office directs the call to the next available idle line.
