An unlisted phone number is a residential phone number that is not published in any phone directory or phone book provided to the general public. Since it would be irrational for a business to have an unpublished number, it applies primarily to residential phone service customers who do not wish for their phone number to be available to the public. While any individual can request that his or her phone number be unlisted, it is a practice common for people who work with the general public, such as doctors, lawyers, politicians, and school teachers.
Prior to the development of more advanced phone technologies such as caller identification, there was no charge to have an unlisted phone number. However, most home phone service providers now charge a small fee for this service because of the complication that it causes to maintain separation in their large databases. An unlisted phone number will not be published in public phone directories or books and will not show up on caller ID displays. Further, it cannot be obtained by calling directory information.
As with all information, phone numbers can be used for negative and illegal actions. Many companies offer to sell unpublished and unlisted phone number information to legal professionals, businesses, and individuals. For residential customers, phone services like privacy manager make it impossible for people with unlisted numbers to call a phone line with privacy services installed without first identifying themselves. While it is virtually impossible to keep a phone number completely private, having it unlisted can significantly cut down on telemarketing phone calls, prank calls, and public invasion.
While anyone with existing phone service can switch a published number to an unlisted phone number, it often makes sense to acquire a new phone number before making it unlisted. Phone companies may work with consumers if there have been problems, such as harassment, that violate the law and help them to acquire a new, unlisted number if necessary.
Information on how an unlisted phone number may impact a person's phone service can usually be obtained from a local phone company.