The phone number display (CLIP) enables the phone number of the caller to be shown on the display of a system phone, an ISDN phone or on a CLIP-capable analogue phone. The prerequisite is that the caller transmits a phone number.

A few CLIP-capable analogue phones support the recording of the date and time in conjunction with the caller list. On some, it is also possible to display the name instead of or in addition to the phone number.