Lucent Technologies 555-661-150 manual Issue

MERLIN LEGEND Communications System Release 6.1	Issue 1
Network Reference 555-661-150	August 1998

2Call-Handling Scenarios

Networking Guidelines Page 2-11

far (over 200 miles) connections and between 21 and 40 for near (under 200 miles) connections. DEFINITY ECS and DEFINITY ProLogix Solutions systems are identified by numbers between 41 and 50 for far connections and between 51 and 60 for near connections.

With a given private network system, all the trunks that connect to another specific system must have the same switch identifier number. For example, if two T1- emulated tie trunks connect System B to System A, System A’s manager must ensure that both of those tandem tie trunks are labelled with the same switch identifier, which is different from the switch identifier that labels a third trunk connecting System A and System C.

It is strongly recommend that each system have a unique pair of identifiers for far and near. If the switch identifiers are not correctly programmed, routing is disrupted. For example, when the switch identifier of the incoming trunk and the automatically selected outgoing trunk for a call match, another route for the call is selected if possible. However, if all available routes specify systems with matching switch identifiers, the caller hears a fast-busy tone. Otherwise, the call would be routed back to the originating system in a continuous loop. This is called automatic immediate cycling.

A trunk that is not a tandem trunk has no switch identifier; this is the factory setting for all trunks. This is how the switch distinguishes tandem trunks from central office lines. To remove a switch identifier, see “Switch Identifiers” on page 19 .

PRI tandem trunks require special programming, much of which is automated for you when a PRI switch type of MERLIN LEGEND-PBX or MERLIN LEGEND-Ntwk is chosen. The switch type for the system at the other end of a PRI tandem trunk is selected during system programming. When MERLIN LEGEND Communications Systems are networked, the switch types at each end of a tandem PRI trunk are different. The scenarios provide examples. See “Tandem PRI Facilities” on page 22 for details.

In Release 6.1 and later systems, the PRI Switch Type Test requests the system at the other end to verify that the correct PRI switch type is programmed. This test should be run only by Lucent Technologies technicians or authorized representatives.

In Release 6.0, outside PRI dial-plan routed and DID calls can be routed to non- local extensions. In Release 6.1 and later systems, this capability has been expanded to all types of PSTN trunks by using calling groups with a single non- local member. Most of the scenarios in this chapter provide examples.