Automatic number identification (ANI) is a feature of telephony

Telephony

In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....

 intelligent network

Intelligent network

The Intelligent Network , is the standard network architecture specified in the . It is intended for fixed as well as mobile telecom networks...

 services that permits subscribers to display or capture the billing telephone number

Telephone number

A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...

 of a calling party. In the United States it is part of Inward Wide Area Telephone Service

Wide Area Telephone Service

In U.S. telecommunications, a Wide Area Telephone Service is a long distance service offering for customer dial-type telecommunications between a given customer [user] station and stations within specified geographic rate areas employing a single telephone line between the customer user location...

 (WATS). ANI service was created by AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

 for internal long distance billing purposes, and is not related to newer caller ID

Caller ID

Caller ID , also called calling line identification or calling number identification or Calling Line Identification Presentation , is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol applications, that transmits a caller's number to...

 services. Inward WATS is purchased by customers so that other telephone users (for example, prospective customers) can call the number toll free. The customer is issued a distinctive toll-free telephone number

Toll-free telephone number

A toll-free, Freecall, Freephone, 800, 0800 or 1-800 number is a special telephone number which is free to the calling party, and instead the telephone carrier charges the called party the cost of the call...

 beginning with a special area code such as 800, or more recently, 888, 877, 866, or 855. Subscribers to these numbers are typically called Inward WATS subscribers.

ANI has two components, information digits, which identify the class of service, and the calling party

Calling party

The calling party is a person who initiates a telephone call over the public switched telephone network, usually by dialing a telephone number....

 billing telephone number.

ANI is also used to describe the functions of two-way radio

Two-way radio

A two-way radio is a radio that can both transmit and receive , unlike a broadcast receiver which only receives content. The term refers to a personal radio transceiver that allows the operator to have a two-way conversation with other similar radios operating on the same radio frequency...

 selective calling

Selective calling

In a conventional, analog two-way radio system, a standard radio has noise squelch or carrier squelch which allows a radio to receive all transmissions. Selective calling is used to address a subset of all two-way radios on a single radio frequency channel...

 that identify the transmitting user.

Privacy

ANI is unrelated to caller ID. A caller's telephone number and line type are captured by ANI service even if caller ID blocking is activated. The destination telephone company switching office can relay the originating telephone number to ANI delivery services subscribers. Toll-free Inward WATS number subscribers and large companies normally have access to ANI information, either instantly via installed equipment, or from a monthly billing statement. Residential Subscribers can obtain access to ANI information through third party companies that charge for the service.

ANI is generally not transmitted when a call is operator assisted, only the area code of the last switch to route the call is sent.

Placing a call through an outbound-only VoIP service or some calling card

Calling card

Calling card may refer to:* Visiting card, a card originally used socially to signify a visit made to a house if the occupant were absent, or as an introduction for oneself; the precursor to the modern business card...

s will cause a non-working number to be sent as the ANI.

Automatic number announcement

Early in its history, ANI was used to provide automatic number announcement

Automatic number announcement circuit

An automatic number announcement circuit is a special telephone number that is meant to be used by phone company technicians and other telecommunications technicians to determine the phone number of a particular line....

, an internal test service for telephone maintenance workers. The service was generally unknown to the public but could be accessed by dialing special numbers reserved for testing purposes.

DNIS

A related service feature available to Inward WATS subscribers is the Dialed Number Identification Service

Dialed Number Identification Service

Dialed Number Identification Service is a service sold by telecommunications companies to corporate clients that lets them determine which telephone number was dialed by a customer. This is useful in determining how to answer an inbound call. The Telecommunications company sends a DNIS number to...

 (DNIS), a code related to the number that the caller dialed when accessing the WATS line. With the information, the service provider can have several toll-free numbers directed to the same call center and provide unique service based on the number dialed. DNIS can also be used to identify other call routing information. For example, the WATS 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)
• UK: Caller Line Identification (CLID)
• Australia: Automatic number identification (ANI) 1800801920 or 12722123 (Telstra line only, local call cost)