An automatic number announcement circuit (ANAC) 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.
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.
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 (respectively), sometimes called plant testing. (One exception is Winnipeg, which reserves 959 only). Numbers within this block are used for various test utilities such as a ringback number (to test the ringer when installing telephone sets), milliwatt tone (a number simply answers with a continuous test tone) and a loop around (which connects a call to another inbound call to the same or another test number). 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 (such as the assignment of entire blocks of 10000 numbers to every competing carrier in every small village to support local number portability schemes) 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 (usually 958).
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 (area code) 958-2580. Conversely, a standard line on which voice service has been unsubscribed (such as an ADSL dry loop) 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.
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, caller ID and prepaid cellphone service became commonplace. These services being more easily exploited for criminal purposes, 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 (although the telephone number is marked on the payphone itself as it is needed to report a non-working coin phone to 6-1-1 repair service).
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 (US only) is easy to remember and, when called, will read back the number after a very short message. A suspended (out of service) line or an incoming only line would not be able to reach any toll-free numbers.
These numbers appear on various lists circulated on-line, many from the 1980s and 1990s. Most were published years ago by Phrack, 2600 Magazine, the alt.2600 Usenet newsgroup (as part of the FAQ) 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.
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 (such as 200, 997, 998, 999) 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' (unassignable) 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.
A few commonly-used 958 or 959 numbers for major incumbent landline carriers:
Numbers otherwise vary arbitrarily by locality:
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 (and might not work) 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 (such as 3-1-1) 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 (506 New Brunswick). 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 555 (telephone number) for other than the standard 555-1212 directory information line.
This service announces the line number on all Eircom 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 +64-8-320-1231 from overseas to test if the (CPN) 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.