Dialing the star symbol and 67 stops a caller's number from showing on caller identification. Star 67, the universal code to deactivate caller ID, is dialed before the number to be called.

Caller ID is a service available through phone companies that provides callers' numbers to the phone of the called party while the phone is ringing. Caller ID also can provide the name of the person calling when the information is available. It is sometimes used by call recipients to avoid taking certain calls, and some people do not answer calls when caller ID information is not displayed.

Caller ID spoofing causes a false number and information to appear on caller ID devices. Marketing companies sometimes use caller ID spoofing to provide a central number for calling back rather than the number for a call center. It is illegal in the United States for marketers to send false caller ID information or to block caller ID. The Federal Communications Commission can issue fines to people or companies that illegally spoof caller ID. Some Internet service providers that provide dial-up Internet access require customers to use caller ID to prevent unauthorized use of accounts. Courts have ruled that caller ID information is not admissible as evidence in court.