Lucent Technologies 555-661-150 manual Merlin Legend Communications System Release

MERLIN LEGEND Communications System Release 6.1	Issue 1
Network Reference 555-661-150	August 1998
2 Call-Handling Scenarios
Network Configuration Scenarios	Page 2-77

■To reach System G, the routes for intersystem voice calls direct them from Systems F and H via the hub, System E, where they are then sent to System G over tandem tie facilities. FRLs for routes to System G are slightly higher to avoid excessive call volume over the analog tandem tie trunks.

NOTE:

In Release 6.1 and later, it is important to note that coverage to the centralized VMS/AA from remote private network systems must be limited to only one span. This means that a call may only pass through one tandem trunk to the centralized VMS/AA on the hub system.

■Calls between extensions on Systems E, F, and H do display caller information, according to display preference settings, at the destination MLX display extensions.

Table 2–20, page 2-82 shows how the system managers set up their local systems for use of local PSTN facilities and non-local PSTN facilities. Remote Access codes are not shown but are set up to be unique and unambiguous across the private network. As you review the table, keep the following points in mind:

■To avoid confusion and for future planning purposes, tandem trunks and pools of tandem trunks are also numbered uniquely and unambiguously.

■System H users do not make Interexchange calls. The system’s loop-start line is assigned to the main pool, Pool 70.

!CAUTION:

Unless networked systems are co-located, each system should have at least one loop-start line connected to the PSTN. The line is required to allow connection of a power-failure telephone to the Power-Failure Transfer (PFT) jack on a module as a power outage backup and for correct routing of emergency and other N11 (911, 411, etc.) calls. To ensure that the correct services are reached, if the loop-start line is used for emergency or other N11 calls, it should be assigned to the main pool. In this case, inter-exchange (IXC) calls determine the number of loop-starts required. Refer to Feature Reference guide for details on the PFT feature.

■The hub system, System E, can support only two tandem PRI trunks to connect to Systems H and F, because it also requires a number of outside facilities. It is using the maximum system capacity of 80 lines/trunks. Its 100D module is in the last circuit module position in the control unit and uses only 20 lines of its 23-line capacity. There is no emergency loop-start line connected to the system, therefore other power failure arrangements should be made. Compare the limitations with those of Scenario 3, shown in Figure 2–4 on page 2–58.