Nortel Networks BCM1000 Benutzerhandbuch

Defining region-based defaults

Installation and Maintenance Guide

The following table provides a description of the types of lines that BRI and PRI trunks 
can provide. These are set under Resources, Media Bay Modules, Bus XX, Module X on 
the Unified Manager.

Note that some of these line types are only available when specific regions are chosen.

Table 58   BRI and PRI line types (DTM and BRI modules) 

T1

digital line that carries data on 24 channels at 1.544 Mbps (North American); 30 channels 
at 2,048 Mbps (Europe)

Loop, E&M, DID and ground start trunks are also versions of T1 lines.

You can program auto-answer T1 loop start, T1 E&M trunks, T1 DID, T1 ground start 
trunks, PRI and IP trunks to map to target lines to provide for attendant bypass (calling 
directly to a department or individual) and line concentration (one trunk can map onto 
several target lines).

DID

This is a type of T1 trunk line that allows an outside caller to dial directly into a line on the 
Business Communications Manager 2.5.

Loop

This is a type of T1 line. This type of line is used on systems where the service provider 
supports disconnect supervision for the digital loop start trunks.

These trunks provide remote access to the Business Communications Manager from the 
public network. This trunk must have disconnect supervision to allow the trunk to be set to 
auto-answer, which provides the remote access portal.

Ground

T1-groundstart trunk

These lines offer the same features as loop start trunks, but are used when the local 
service provider does not support disconnect supervision for digital loop start trunks. 
Ground start trunks work with T1 only. By configuring lines as ground start, the system will 
be able to recognize when a call is released at the far end.

E&M

T1 and E&M. This type of trunk line is used to create simple network connections to other 
phone systems.

This trunk always operates in a disconnected supervised mode.

PRI

ISDN interface with 23 B channels and 1 D channel at 1.544 MBps (in Europe: 30 B 
channels and 2 D channels at 2.048 Mbps)

This is the module that controls system timing.

These lines give you incoming and outgoing access to an ISDN network and are 
auto-answer trunks, by default. 

These lines provide a fast, accurate and reliable means of sending and receiving data, 
images, text and voice information. using PRI lines allows for faster transmission speeds 
and the addition of a variety of powerful business applications, including remote LAN 
access, video conferencing, file transfer and internet access.

BRI

ISDN loop that provides both T, S and U2 and U4 (region-specific) reference point loops.

These loops can support both network (T and S loops) and terminal equipment (S loop) 
connections.

This type of line provides incoming and outgoing access to an ISDN network. ETSI ISDN 
BRI is the European Telecommunications Standards Institute specification for BRI ISDN 
service. BRI provides two bearer B-channels operating at 64 kbits/s and a data D-channel 
which operates at 16 kbits/s. The D-channel is used primarily to carry call information. Like 
loop start trunks, BRI lines can be configured as manual-answer or auto-answer. 

DASS2

(British) Trunk provides multi-line IDA interconnection to the British Telecom network.