Lucent Technologies 8.2 User Manual

Issue 1

April 2000

Features and technical reference 

1564

Trunks and Trunk Groups 

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In a call involving more than one telephone, one of the telephones may 
press the Flash button, and another telephone may dial the phone number. 
The telephone that dials the phone number is not required to have a Flash 
button.

■

If the far-end/CO does not support custom services, the call may be 
dropped by the far-end/CO on sending the flash signal or the signal may be 
ignored and a click-click sound is heard.

Trunks connect DEFINITY ECS to other pieces of equipment (adjuncts) and to 
other switches. In general, trunks connect your switch to one of four things:

■

the public telephone network

■

a private telephone network

■

the Internet or a private intranet

■

switch adjuncts, such as a loudspeaker paging system or a source for music 
or announcements

When trunks of the same type are used for the same application, assign them to 
the same trunk group. A trunk group allows you to assign service characteristics to 
the group rather than administering each trunk individually.

Trunks and access endpoints consume the same resource. The sum of trunks 
and access endpoints cannot exceed the total number of trunks allowed on 
your system.

This chapter contains information about the most common analog and digital 
trunks. Specialized trunks such as Advanced Private-Line Termination (APLT), 
tandem, release-link, and DMI-BOS trunks are not covered in this manual. Refer 
to DEFINITY ECS Administration for Network Connectivity for information on 
these trunks.

DEFINITY ECS supports the following basic trunk types.

Used in Electronic Tandem Networks (ETN), access trunks connect satellite 
switches to the main switch. Unlike tandem trunks, access trunks do not carry 
traveling class marks (TCM) and thus allow satellite callers unrestricted access to 
out-dial trunks on the main switch.