Automatic number announcement circuit


An automatic number announcement circuit is a component of a central office of a telephone company that provides a service to installation and service technicians to determine the telephone number of a line. The facility has a telephone number that may be called to listen to an automatic announcement that includes the caller's telephone number.
The ANAC number is useful primarily during the installation of landline telephones to quickly identify one of multiple lines.

Operation

A technician calls the local telephone number of the automatic number announcement service. This call is connected to equipment at a local central office that uses a voice synthesizer or digital samples to announce the telephone number of the line calling in. The main purpose of this system is to allow telephone company technicians to identify the telephone line they are connected to.
Automatic number announcement systems are based on automatic number identification, and meant for phone company technicians, the ANAC system works with unlisted numbers, numbers with caller ID blocking, and numbers with no outgoing calls allowed. Installers of multi-line business services where outgoing calls from all lines display the company's main number on call display can use ANAC to identify a specific line in the system, even if CID displays every line as "line one".
Some ANACs are very regional or local in scope, while others are state-/province- or area-code-wide: there appears to be no consistent national system for them. Most are provider-specific. Every telephone company, whether large or small, determines its own ANAC for each individual central office, which tends to perpetuate the current situation of a mess of overlapping and/or spotty areas of coverage. No official lists of ANAC numbers are published as telephone companies believe overuse of these numbers could make them more likely to be busy when needed by installers.

958 local test exchanges

Under the North American Numbering Plan, almost all North American area codes reserve telephone numbers beginning with 958 and 959 for internal local and long-distance testing, sometimes called plant testing.. Numbers within this block are used for various test utilities such as a ringback number, milliwatt tone and a loop around. ANAC numbers can also appear in the 958 range, but there is no requirement that they reside there.
In some area codes, multiple additional prefixes had been reserved for test purposes, in addition to the standard 958 and 959. Many area codes reserved 999; 320 was also formerly reserved in Bell Canada territory. As widespread inefficiencies in numbering have created shortages of available numbers, these prefixes are often "reclaimed" and issued as standard exchanges, moving the handful of numbers in them to one standard test exchange.
Some carriers have been known to disable payphone calls to 958 or 959 test lines, such as Bell Canada's system-wide ANAC line at 958-2580. Conversely, a standard line on which voice service has been unsubscribed may still accept calls to the 958 test exchange but not allow calls to standard numbers. This "soft disconnect" condition is intended to allow calls to 9-1-1 emergency services and to the telco business office to order telephone service, but to no other numbers.

Tollfree numbers

Some large telephone companies have toll-free numbers set up. In most cases, these numbers remain undisclosed to prevent abuse, but MCI maintains this widely published, toll-free ANAC: 1-800-437-7950. This is distinct from technical support and other lines which use ANI so that a computer can automatically display the customer's account on a "screen pop" for the next available customer service representative: the MCI number is intended specifically for ANAC use.
Formerly, some companies changed their ANAC number every month for secrecy; this is still the case with a few numbers. In one example of this concern, most payphones in the United States are assigned a telephone number and can ring if the number is called. The phone can then be used to make and receive calls by anyone, making it a potential tool in anonymous criminal activity such as narcotics trafficking. Where a payphone does not have any number listed on the unit, the number can be discovered by calling an ANAC service.
Late in the 20th century, after caller ID and pre-paid cell phone service became commonplace and with these services being more easily exploited for criminal purposes, especially in the case of burner phones, this type of abuse of payphones faded from concern. In Canada, this behaviour has always been more difficult. As a matter of course, incoming calls to payphones are disabled; furthermore, the Bell ANAC number is also disabled.
There are some private national toll-free numbers that use ANI and then have a computer read back the number that is calling, but these are not intended for use in identifying the customer's own phone number. They are used in order for the agent in the call center to confirm the phone the customer is calling from, so that a computer can automatically display the customer's account on a "screen pop" for the next available customer service representative; they are distinct from purpose-made toll-free ANAC numbers. Regardless, if one were to call one of these numbers, listen for the number confirmation and hang up, they would in effect be using this system as if it were an ANAC.
One such toll-free service is one owned by MCI - 1-800-444-4444. This number is easy to remember and, when called, will read back the number after a very short message. A suspended line or an incoming only line would not be able to reach any toll-free numbers.

ANAC numbers

These numbers appear on various lists circulated on-line, many from the 1980s and 1990s. Most were published years ago by Phrack,, the alt.2600 Usenet newsgroup or phone phreaks and are now hopelessly outdated. The information is not reliable, as numbers change often. Many of the listed numbers no longer work.
The list is presented by area code, number and location. In some regions, there are several numbers, depending on the telephone company or the area code of the caller, as there can be several central offices serving some areas.

United States

The North American Numbering Plan reserves 958-XXXX and 1-NPA-959-XXXX for local and long-distance test numbers in almost all USA and Canadian area codes.
Frequently, a prefix outside the 958 or 959 range was also listed as a test exchange, only to be reclaimed and issued as a block of standard numbers at a later date. NANPA's utilised codes report will indicate 'UA' for valid test prefixes; if a formerly 'UA' code newly appears on the available list or becomes an active exchange, any former test numbers from its time as a reserved prefix are presumed invalid and deprecated. N11 prefixes such as 211, 311 and 511 are also disappearing as test numbers as these codes are reassigned to local services such as city, community or highway information.
;958, 959 test prefixes: The standard location for test numbers in most NANP area codes, although specific local numbers vary. 1-NPA-959 traditionally contained long-distance test numbers, but this convention is often ignored; AT&T's 959-1122 and GTE 's 959-1114 are local. Some area codes will flag additional codes as 'UA' or unassignable, in some cases reserving them for test numbers.
A few commonly-used 958 or 959 numbers for major incumbent landline carriers:
Numbers otherwise vary arbitrarily by locality:
;Other regionally nonassignable test prefixes: These are, over time, being phased out. As each reservation consumes a block of 10000 numbers, the prefixes are increasingly being recovered for use as regular exchange codes and the test numbers moved to 958-XXXX. If the number is active for test, the prefix listed remains within a block currently marked by NANPA.com as unassignable in the one specified area code. These test numbers will be shut down before the 'UA' flag is removed, the prefix made available or reassigned as a standard exchange.
;Vertical service codes, carrier-specific: Most vertical service codes are activated with #, * or a leading 11- and are internal to an individual landline or wireless carrier. This block mostly contains codes to activate or deactivate features such as call forwarding, but rarely a test number may appear in this set.
;Long-distance carrier-specific: Area code 700 is reserved for carrier-specific numbers operated by interstate long-distance providers, such as AT&T. With the exception of 1-700-555-4141, all of these are LD carrier-specific. Area code 700 is therefore rarely used.
;Area code 1-200: There is no non-geographic area code 200, although exchange 1-NPA-200-XXXX now exists in many local area codes. The 1-200 area has occasionally been used as an unused space in which to place test numbers, but is rare as in most communities a 1- indicates a long-distance trunk call.
;Local numbers: These are regular numbers within valid local exchanges in the communities listed. Many belong to competitive local exchange carriers or independent telephone company exchanges. Supposedly, a test call gives an automatic announcement. Some may announce caller ID instead of ANI; these will incur a toll for calls outside their home area. These are unverified; there is a risk these will be reassigned to individual subscribers:
;N-1-1 numbers: These are mostly dead, except in rare locations where some of the standard information numbers have not yet been assigned to their usual function. The corresponding test number will stop working when 2-1-1 becomes community info, 3-1-1 becomes city or county hall, 4-1-1 becomes directory info or 5-1-1 provides highway conditions, for instance. With rare exception, one should not expect these numbers to be valid.
Please note that it is always preferable to call the local ANAC; only if the local ANAC number can not be called is it advisable to call a toll-free ANAC number. It is also preferable to call an open ANAC rather than the password-protected one given below.
The below numbers are not true ANAC numbers; however, they do read back one's phone number. These numbers provide valuable services to the customers they serve; it is, therefore, inadvisable to misuse them.
The current use of exchange prefixes for each area code is listed by CNAC; if an exchange changes from "plant test" to reclaimed or active, any former test numbers with the associated prefix are invalidated. Commonly-used test numbers for major carriers include:
Additional plant test codes may be in use locally in some areas:
Occasionally, a number in an existing, standard local exchange in the area is used. These will incur a toll outside their home area. Some may be announcing caller ID, which is not the same as ANI. As standard local calls, they are not accessible from ADSL "dry loop", inbound-only or unsubscribed lines:
In Bell Canada territory, +1-areacode-320 was formerly reserved for 320-xxxx test numbers; these were moved to the 958-xxxx range and 320-xxxx reclaimed for use as a standard exchange. The use of N11 prefixes for test numbers is also deprecated as 3-1-1 now often reaches city hall or municipal services while 2-1-1 is local community information.
Some lists erroneously mention 1-555-1313 as ANAC. The purpose of +1-areacode-555-1313, a pay-per-use "name that number" reverse lookup information service introduced in the mid-1990s, differs from ANAC. ANAC announces the caller's own number; the reverse lookup gives the directory name for a listed telephone number input by the user. 555-1313 is one of the rare uses of the 555 exchange for other than the standard 555-1212 directory information line.

United Kingdom

This service announces the line number on all Eir lines, including lines where calls are carried by another provider using carrier preselect.
The same number also works for Smart Telecom lines provided by local-loop unbundling.
The number is called out without the leading 0. For example, 021 XXX XXXX is read back as "21 XXX XXXX".
There is also an extended ANAC service for identifying which carrier handles calls. Dialling these numbers will cause the local switch to announce which carrier the calls are being routed through for a specific category of calls.
Subscribers may also dial +64 320-1231 from overseas to test if the Caller ID number is being passed on to New Zealand; this should announce the area code and local number as it appears on call display.

South Africa