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.
Caller ID was a device invented by David Goldfarb in 1965 while with the Saskatchewan River Widget Works in Edmonton, Canada. Based on technology "borrowed" from the Race, it allowed a telephone receiving a call to identify the number of the phone sending the call. Goldfarb first used it to identify the telephone numbers of the henchmen of crime boss Basil Roundbush, who were targeting Goldfarb's life in retaliation for Goldfarb's refusal to continue as Roundbush's errand runner. He informed the local police with this information, and made several sales of the device to the local constabulary. Goldfarb was later dismayed to learn that Roundbush had his own Lizard-based device which negated the Caller ID.
Goldfarb's invention is never given a formal name, or even a consistent slang name, within the series. This article uses the OTL name for convenience.