Automatic number identification (ANI) is a feature of a telecommunications network for automatically determining the origination

telephone number A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices f ...

on toll calls for billing purposes. Automatic number identification was originally created by the

American Telephone and Telegraph Company AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...

(AT&T) for long distance service in the Bell System, eliminating the need for telephone operators to manually record calls. Modern ANI has two components: information digits, which identify the class of service, and the

calling party The calling party (in some contexts called the "A-Number") is a person who (or device that) initiates a telephone call. The person who, or device that, receives a telephone call is the called party (or callee or B-party). In some countries, it ...

billing telephone number. The term is also used to describe the functions of

two-way radio A two-way radio is a radio that can both transmit and receive radio waves (a transceiver), unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and receiver in one unit, used for bidirection ...

selective calling that identify the transmitting user. ANI is distinct from newer

caller ID Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call i ...

services, such as call display, which are solely for informing a subscriber.

Toll-free telephone numbers

Modern

toll-free telephone number A toll-free telephone number or freephone number is a telephone number that is billed for all arriving calls. For the calling party, a call to a toll-free number from a landline is free of charge. A toll-free number is identified by a dialing pre ...

s, 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 with 833 and 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. A caller's telephone number and line type are captured by ANI service even if

caller ID blocking Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller (telecommunications), caller's telephone number to the called party's telephone ...

is activated. The destination telephone company switching office can relay the originating telephone number to ANI delivery services subscribers. Toll-free subscribers and large companies normally have access to ANI, 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.{{cn, date=November 2022

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 is the ,Andrew
A Practical Guide to Call Center Technology. p315. {{Webarchive, url=https://web.archive.org/web/20140628160252/http://books.google.com/books?id=pyguvxndiogC&pg=PA315&lpg=PA315&dq=at%26t+dnis&source=bl&ots=dRVcDwKkRz&sig=Wk3_lj9i68Ur63tUpk_Np28uM94&hl=en&ei=rSAKS8_jNdKWtge20ryzCg&sa=X&oi=book_result&ct=result&resnum=3&ved=0CA8Q6AEwAjge#v=onepage&q=at%26t%20dnis&f=false>Waite, , date=2014-06-28 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 The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

Caller Line Identification Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call i ...

(CLID) * Australia: Automatic number identification (ANI) 1800801920 or 12722123 (Telstra line only, local call cost)

References

{{Reflist {{Telecommunications Anonymity Telephony signals