MERLIN LEGEND Communications System Release 5.0
Feature Reference
555-650-110
Issue 1
June 1997
Features
Page 448
Primary Rate Interface (PRI) and T1
call-by-call service selection, which allows multiple network services over the
same B-channels. The D-channel conveys signaling required to set up, control,
and clear calls made over all of the B-channels.
The most common configuration of a DS1 facility for PRI consists of 23
B-channels and 1 D-channel, although other combinations are possible. Each PRI
must include a D-channel, but may include fewer than 23 B-channels. The
remaining channels cannot be used for any other purpose.
Figure 36.
PRI Lines and B-Channel Groups
NOTE:
The MERLIN LEGEND Communications System does not support multiple
PRI facilities sharing one D-channel (as allowed with Non-Facility
Associated Signaling).
Up to three DS1 carrier facilities (maximum of two in one carrier), and therefore
three PRIs, can be connected to the system through separate 100D modules,
each of which occupies a slot in the system carrier. In terms of system capacity,
each DS1 channel counts as a line/trunk, so the maximum number of B-channels
supported by the system is 69. Signaling for 69 B-channels is provided over 3
separate D-channels, using up 72 of the system’s 80-line capacity.
OUTGOING LINE
IS SELECTABLE
BY USER
Line 801
Line 802
Line 803
Line 804
PRI
Line 849
PRI
Line 850
PRI
Line 851
PRI
Line 852
B-channels
B-CHANNEL
GROUP
Trunks:
Loop-start
Ground-start
DID
Tie
PRI