Caller ID is a telephone service 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 original technology was patented during a period from 1969 to 1975 by inventor Theodore George “Ted” Paraskevakos, but caller ID did not become commonplace until nearly two decades after that.