caller identification(Caller ID (caller identification, CID), also called calling line identification (CLID) or calling number identification (CNID) or Calling Line Identification Presentation (CLIP), 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. wiki Alexander Demidov)
