Caller ID (caller identification, CID), also called calling line identification (CLID) or calling number identification (CNID), is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol (VoIP) applications, that transmits a caller's number to the called party's telephone equipment during the ringing signal, or when the call is being set up but before the call is answered. Where available, caller ID can also provide a name associated with the calling telephone number. The information made available to the called party may be displayed on a telephone's display or on a separately attached device.
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Caller ID (caller identification, CID), also called calling line identification (CLID) or calling number identification (CNID), is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol (VoIP) applications, that transmits a caller's number to the called party's telephone equipment during the ringing signal, or when the call is being set up but before the call is answered. Where available, caller ID can also provide a name associated with the calling telephone number. The information made available to the called party may be displayed on a telephone's display or on a separately attached device.