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 2-18

Tandem PRI trunks provide the following benefits:

■Faster General Performance. PRI facilities make faster connections across private networks for ARS calling over tandem trunks as well as faster intersystem call handling.

■Faster Data Transmission. Networked PRI tandem trunks support digital data speeds of up to 128 kbps between networked systems for enhanced 2B data videoconferencing and other data applications. Earlier releases permitted a maximum speed of 112 kbps between connected systems.

NOTE:

If you plan to communicate at 64 or 128 (2B data) kbps, use extended superframe (ESF) format with Bipolar 8-Zero Substitution (B8ZS) line coding. Some service providers charge more for this type of T1 circuit. However, it not only allows the higher speed, it is also less susceptible to line errors than other format and coding combinations and can be maintained without taking the facility out of service.

■Better Call-Handling Displays. Intersystem calls via networked PRI facilities can provide the caller’s extension label (for example, caller name), extension number (factory setting), or both name and number at the recipient’s MLX telephone display. Scenario 1 shows the details for different types of telephones.

■Lower Service Provider Costs. When you use PRI over a private network, you order a point-to-point T1.5 circuit from your service provider, then program the PRI service yourself rather than leasing it from the service provider. When networked systems are distant, the service provider may need to provide amplification but not PRI switching services.

■Fractional Use Support. You may place drop-and-insert equipment between systems connected by a PRI tandem trunk, allowing use of fewer than 23 B-channels. The dropped channels are generally used for dedicated data/video service, and the remaining channels carry voice traffic. The equipment must never drop Channel 24, the D-channel. All channels do count towards the system maximum of 80 lines.

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Automatic Number Identification (ANI)/Incoming Call Line Identification (ICLID). If PRI tandem trunks are used, ANI and ICLID information may display at the destination extension.

Better Transfer Handling. When a user manually transfers a call across the private network on tandem PRI trunks and the transfer recipient’s extension is either busy or has turned on Do Not Disturb and has no coverage available, the call returns to the transfer originator. If a call is transferred over tandem tie trunks, or is transferred with automatic completion over tandem PRI trunks, it does not return to the originator when the intended destination is unavailable.