Automatic number identification

Modern toll-free telephone numbers, which generate itemized billing of all calls received instead of relying on the special fixed-rate trunks of the Bell System's original Inward WATS service, depend on ANI to track inbound calls to numbers in special area codes such as +1-800, 888, 877, 866, 855, 844, and 833 with 822 reserved for future toll free use (United States and Canada), 1800 (Australia) or 0800 and 0808 (United Kingdom). ==Privacy==

ANI is conceptually and technically different from caller ID service. ==Automatic number announcement==

ANI is used to provide automatic number announcement, a test facility of a central office for telephone installation technicians. The service, which is not advertised to the public, allows an installer to identify a line by dialing a telephone number. Such numbers are typically assigned in a a range reserved for testing purposes (such as 958-xxxx in much of North America). ==DNIS==

Dialed Number Identification Service (DNIS) is a related service feature available to private branch exchange subscribers. It transmits information about the destination number, which a service provider can use to have several toll-free numbers directed to the same call center and provide unique service. DNIS can also be used to identify other call routing information. For example, toll-free service can be configured to send a specific DNIS number that is assigned to callers from geographic regions based on city, area code, state, or country. ==Similar services==

• Europe: Calling Line Identification (CLI) • United Kingdom: Caller Line Identification (CLID) • Australia: Automatic number identification (ANI) 1800801920 or 12722123 (Telstra line only, local call cost) ==References==