Terminology

Calling Line Identification (CLI) is the telephone number of the remote caller in an incoming call scenario.

The destination of a call specifies where the call terminated. The destination will display different information for each type of call:

Call type	Information displayed
Incoming calls	The name of the user whose extension answered the call, or the extension number if not available;
Outgoing calls	The network or geographical location that was dialled, or an alias if defined in your contacts list;
Internal calls	The extension that was dialled, enclosed in square brackets [ ].

The name of the destination called, e.g. Manchester, Tri-Line, London.

The ID of the destination called.

A tandem call is a connecting call in a telephone network, coming into a switch through one line and transferred out again through another.