calling line identification (ISDN) (CLI)

Calling Line Identification, abbreviated to CLI or CLID, is a service feature of digital networks. Calling Line Identification is the display of the calling party's telephone number on the called party's display.

Calling line identification can be suppressed by the calling party by means of Calling Line Identification Restriction( CLIR).

Calling Line Identification (CLI), Photo: Comtech

One of the advantages of CLI is that the called party can identify the caller before accepting the call. The CLI number can be stored in the phone book of the terminal.

Caller ID is also supported by the local exchange in the classic analog POTS (Plain Old Telephone Service).