Lucent Technologies 555-661-150 manual Call information indicating

MERLIN LEGEND Communications System Release 6.1				Issue 1
Network Reference 555-661-150				August 1998
1 Introduction
	Tandem Trunking and Tandem Switching			Page 1-12
	Touch Tone Receivers	None	✔	Required for all calls routed across the
				private network on tie trunks. (Voice
				messaging increases traffic in both
				directions.) Not required on PRI trunks.
	Centralized Voice Messaging
	■ Call information indicating	✔		With PRI, the call information signals
	inside call			sent by the remote system to the
				centralized VMS indicates inside calls.
				With tie trunks, the call information
				signals for all calls indicates an outside
				call.
	■ Message Waiting light updates	✔	✔	With PRI, the Message Waiting lights are
				updated on the signalling D-channel.

With tie trunks, Message Waiting lights updates are sent as separate voice calls and must compete with other voice and data calls for an available tie trunk and touch tone receiver. As a result, the Message Waiting light updates may be delayed on tie trunks.

The advantages of tandem PRI facilities are illustrated in practical terms in Chapter 2, “Call-Handling Scenarios.” However, tandem PRI trunks do present the following challenges that affect your configuration planning.

■Each PRI facility connected to a system, whether it is a tandem trunk or an outside facility and whether or not drop-and-insert equipment is used between systems, takes up 24 of the 80-line capacity of a MERLIN LEGEND Communications System.

■Each 800 NI-1BRI module takes up to 16 of the 80-line capacity.

■Each 400EM tie module takes up to 4 of the 80-line capacity.

In view of this fact and the differences noted in Table 1–1, we will briefly revisit the private network configurations we looked at earlier.

The next three figures show basically the same configurations that you saw before, slightly modified to emphasize the differences among them. The figures shown are only a few examples for illustration, and do not represent all possible configurations. In these figures, the lines and trunks literally represent the number of facilities connected to each system in a given configuration. The PSTN facilities shown here are only examples. You can connect the same types of loop-start, ground-start, T1 Switched 56, DID (Direct Inward Dialing), and T1-emulated analog lines/trunks to a private network system that you can to a non-networked system.

!SECURITYlALERT:

Do not connect T1-emulated loop-start lines or analog loop-start lines without reliable disconnect to any switch that is part of a private network.