Basic Rate Interface (BRI) Feature

Description: Terminology

Lines/Trunks

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

Digital Subscriber Line (DSL) refers 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

In general, the Directory Number (DN) 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 DN as the Called Party Number. Only one call to a particular DN is accepted at any one time. The DN is usually a subset of the Service Profile Identifier (SPID). Only the DNs for the hunt group are unrelated to the SPIDs.

ISDN Ordering Code

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 MAGIX Integrated 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

A multiline hunt group can be programmed at the central office to send calls to a number of separate 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 central office 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.

In order to know the available options of Multiline Hunt Group and to set it up correctly, you must find out what type of switch your central office uses.

For the different switches, Multiline Hunt Group has the following capabilities:

5ESS - Multiline Hunt is available for voice-only and digital data-only applications. Multiline Hunt capability is provided under a switch feature called Series Completion. Do not use the 5ESS feature named Multiline Hunt Group. For alternate voice and digital data applications, special central office features (such as call forwarding) are also required in the line provisioning. As a result, this configuration may not be supported by some of the Regional Bell Operating Companies (RBOCs) or other local carriers.
DMS-100 - Multiline Hunt is available for voice-only, digital data-only, and alternate voice and digital data applications.
EWSD - Multiline Hunt capability is provided under a switch feature called Series Completion. It is limited to six DSLs in a group, however, and may not be supported by some central offices. Do not use the EWSD feature named Multiline Hunt Group. Multiline Hunt is available for voice-only and digital data-only applications. Alternate voice and digital data applications are not supported.

Multiline Hunt is not part of IOC package S. If Multiline Hunt is needed, you must order the appropriate feature and inform the central office of the switch settings that you need (see Appendix H of System Planning).

Called Party Number

In general, the term Called Party Number (CdPN) denotes a telephone number that has been dialed to reach a destination. While routing the call, however, the network can change the Called Party Number to make routing easier. In either case, the network sends the Called Party Number to the system when a call arrives at the system. Depending on the type of call, the called party number may be displayed on the second page of the 4412D+, 4424D+, 4424LD+, MLX, or ETR telephone display.

4400, 4400D, 4406D+, TransTalk 9031/9040, Business Cordless 905, and MLS telephones do not display Called Party Number information.

Calling Party Number

The Calling Party Number (CPN) provides incoming calling party number information that identifies the originator of a call in the call-handling displays of 4400-Series, MLX, TransTalk 9031/9040, Business Cordless 905, ETR, or MLS telephones. If the owner of the MERLIN MAGIX Integrated System subscribes to this BRI feature, each incoming call to the system over a BRI line can be accompanied by the CPN or by the billing number of the calling party supplied by the network.

If the calling party subscribes to the central office Directory Number Privacy feature, no number is received.
Calling Party Number on BRI lines is not the same as Calling Party Number in Caller ID. Caller ID occurs on loop-start lines

Service Profile

A Service Profile (SP) defines the interface on a BRI line between the central office and an ISDN terminal. It specifies the parameters and their values necessary to provide services to the terminal.

Service Profile Identifier

A Service Profile Identifier (SPID) is a unique identifier used by the central office to associate an ISDN terminal with a Service Profile. It is provided by the central office at subscription time. The System Manager must program the SPID for each BRI line to bring the BRI line into service (activate). If dial tone is received, then the correct SPID has been programmed.

Topics

Description

	Terminology
	Clock Synchronization
	Clock Switching
	Timers and Counters
	Call Processing

At a Glance

Considerations & Constraints

System Programming

Feature Interactions