Automatic number announcement circuit
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.
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.[1] 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.[2]
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 (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.
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.[disputed – discuss] 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 (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.[3] A suspended (out of service) line or an incoming only line would not be able to reach any toll-free numbers.
ANAC numbers
This section needs to be updated.(December 2014) |
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[4] (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.
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 (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.
- 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 (Verizon)'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:
- 958, as a three-digit number in many former NYNEX/Bell Atlantic areas, now Verizon or FairPoint (207 Maine, 212 New York, 215 Pennsylvania, 315 New York, 413 Massachusetts, 508 Massachusetts, 516 New York, 603 New Hampshire, 609 New Jersey, 610 Pennsylvania, 617 Massachusetts, 718 New York, 732 New Jersey, 856 New Jersey, 958 New Jersey)
- 959-1114 Verizon, for all former GTE points in California (area codes 310, 714, 760, 805); also Southwestern Virginia (276), Farmersburg/North Terre Haute/South Terre Haute/Riley Indiana (812) and Durham, North Carolina (919)
- 959-1122 PacBell (AT&T), all points (California area codes 209, 213, 310, 408, 415, 510, 530, 619, 650, 714, 760, 805, 831, 909, 916 and 925)
- 959-1122 Southwestern Bell (AT&T), (417 Missouri, 620 Kansas, 816 Missouri, 913 Kansas, 817 Texas, 972 Texas and 682 Texas)
- 959-3111 CenturyLink All circuits
Numbers otherwise vary arbitrarily by locality:
- 216: 959-9892 Akron/Canton/Cleveland/Lorain/Youngstown, Ohio
- 301: 958-9968 Hagerstown/Rockville, Maryland
- 309: 959-1114 Central Illinois (Frontier, Ex-Verizon)
- 309: 959-9833 Quad City Illinois Area (AT&T)
- 412: 959-1114 Pittsburgh Pennsylvania (Verizon)
- 503: 958 Portland, Oregon (CLEC, MCIMetro ATS)
- 602/623/480: 958-7847 Phoenix Metro Area (Qwest)
- 610: 958-4100 Allentown/Reading, Pennsylvania
- 717: 958 Harrisburg/Scranton/Wilkes-Barre, Pennsylvania <CenturyLink: "Sorry but your call can not be completed">
- 724: 959-1114 Pittsburgh Pennsylvania (Verizon)
- 787: 787-959-1240 Puerto Rico (PRTC)
- 787: 787-959-1250 Puerto Rico (PRTC)
- 805: 959-1123 Bakersfield/San Luis Obispo, California (?) (Returns DTMF Tones)
- 814: 958-2111 Cresson, Pennsylvania
- 850: 959-3111 Tallahassee, Florida
- 860: 959-9822 Connecticut
- 919: 959-1031 Raleigh/Cary/Apex, North Carolina area. (BellSouth/AT&T) Dial as 7-digits.[5]
- 919: 959-1041 Raleigh/Cary/Apex, North Carolina area. (BellSouth/AT&T) Dial as 7-digits.[5]
- 970: 958-(any 4 digits) Greeley, Colorado (Qwest)
- 973: 973-959-3111 Northern New Jersey (Centurylink)
- Other regionally nonassignable (UA) 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 (usually) to 958-XXXX. If the number is active for test, the prefix listed (often 200, 990, 997, 998, 999) remains within a block currently marked by NANPA.com as unassignable[6] in the one specified area code. These test numbers will be shut down before the 'UA' flag is removed, the prefix made available[7] or reassigned as a standard exchange.
- 210: 830 Brownsville/Laredo/San Antonio, Texas
- 214: 970-222-2222 Dallas, Texas (Southwestern Bell)
- 214: 970-611-1111 Dallas, Texas (Southwestern Bell)
- 312: 200 Chicago, Illinois (Ameritech)
- 313: 200-200-2002 Ann Arbor/Dearborn/Detroit, Michigan
- 313: 200-222-2222 Ann Arbor/Dearborn/Detroit, Michigan
- 313: 200-200-200-200-200 Ann Arbor/Dearborn/Detroit, Michigan
- 315: 998 Syracuse/Utica, New York
- 412: 975 Pittsburgh, Pennsylvania (Verizon)
- 508: 200-222-1234 Fall River/New Bedford/Worcester, Massachusetts
- 508: 200-222-2222 Fall River/New Bedford/Worcester, Massachusetts
- 508: 260-11 Fall River/New Bedford/Worcester, Massachusetts (Verizon)
- 512: 830 Austin/Corpus Christi, Texas
- 513: 380-55555555 Cincinnati/Dayton, Ohio
- 518: 997 Albany/Schenectady/Troy, New York
- 518: 998 Albany/Schenectady/Troy, New York
- 607: 993 Binghamton/Elmira, New York
- 617: 200-222-1234 Boston, Massachusetts
- 617: 200-222-2222 Boston, Massachusetts
- 617: 200-444-4444 Boston, Massachusetts (Woburn, Massachusetts)
- 617: 220 Boston, Massachusetts (Verizon)
- 617: 220-2622 Boston, Massachusetts (Verizon)
- 618: 930 Alton/Cairo/Mt. Vernon, Illinois
- 724: 975 Pittsburgh, Pennsylvania (Verizon)
- 781: 200-222-2222 Boston, Massachusetts
- 810: 200-200-200-200-200 Flint/Pontiac/Southfield/Troy, Michigan
- 817: 970-611-1111 Ft. Worth/Waco, Texas (Southwestern Bell)
- 817: 970-1234 Ft. Worth, Texas (AT&T / SBC)
- 914: 990-1111 Peekskill/Poughkeepsie/White Plains/Yonkers, New York
- 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.
- 515: 552# Des Moines Metro Area (CLEC), Iowa
- 434: 118 Charlottesville, Virginia (Verified 2013)
- 732: *99 Central New Jersey (Optimum Phone Service)
- 802: 111-2222 Vermont
- 909: 111 Riverside/San Bernardino Counties, California (GTE) <This is the GT Ringback/Trust Territory of the Pacific Islands code, no Idaho here>
- 909: 114 and 959-1114 Ontario/Pomona/San Bernardino, California (Current for all GTE switches in California)
- 914: *99 Westchester County, New York (Cablevision/Optimum Voice)
- 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 (which identifies the default interexchange carrier on a line), all of these are LD carrier-specific. Area code 700 is therefore rarely used.
- 802: 1-700-222-2222 Vermont[citation needed]
- 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 (if it has not been explicitly reserved). 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.
- 312: 1-200-555-1212 Chicago, Illinois
- 312: 1-200-8825 Chicago, Illinois (Last Four Change Rapidly)
- 708: 1-200-555-1212 Chicago/Elgin, Illinois
- 708: 1-200-8825 Chicago/Elgin, Illinois (Last Four Change Rapidly)
- 906: 1-200-222-2222 Marquette/Sault Ste. Marie, Michigan
- 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 (if they work at all) for calls outside their home area. These are unverified; there is a risk these will be reassigned to individual subscribers:
- 209: 888-6945 Stockton, California (Reads ANAC and CNAM) (out of service, returns false answer supervision 2014)
- 334: 557-2311 Montgomery, Alabama (CLEC) (no answer, 2014)
- 334: 557-2411 Montgomery, Alabama (CLEC) (busy/no answer, 2013)
- 419: 353-1206 Bowling Green, Ohio (Frontier) (Verified March 2022 - Works from Verizon, but not from AT&T and VoIP carriers)
- 503: 266-1021 Canby-Needy, Oregon (Canby Telephone Association, independent, returns ANI) (Verified March 2022, but does not supervise; will not work via Google Voice)
- 503: 697-0053 Clackamas/Lake Oswego, Oregon (Qwest, returns Caller ID) (Verified May 2018, but will only work when calling from the Centurylink Lake Oswego exchange)
- 505: 243-0049 Albuquerque, New Mexico (Quest, returns Caller ID, additional test menu) (Verified March 2022)
- 508: 200-5555 Worcester, Massachusetts (Dial 7 digits—City VZ landlines only?) (Verified September 2019 via Worcester 5ESS)
- 515: 280-1241 Des Moines, Iowa (Qwest, returns Caller ID, additional test menu) (Verified March 2022)
- 541: 330-0024 Bend, Oregon (Qwest, returns Caller ID, additional test menu) (Verified March 2022)
- 561: 364-1781 Boynton Beach, Florida (Bellsouth, West Palm Beach/Jupiter/Juno Beach, returns Caller ID) (out of service, dead air, March 2022)
- 570: 674-0086 Dallas, Pennsylvania (Frontier/Commonwealth Telephone) (Verified March 2022)
- 602: 253-0227 Phoenix, Arizona (Qwest) (No answer, February 2018) (Reassigned to customer December 2019)
- 608: 884-1206 Edgerton, Wisconsin (Frontier North, 7 digits only, returns Caller ID) (Verified March 2022)
- 702: 889-4579 Las Vegas, Nevada (CenturyLink) (no answer, 2014) (No answer, February 2018)
- 712: 343-1206 Avoca, Iowa (Windstream) (Verified, October 2022)
- 747: 268-1966 La Cañada Flintridge, California (FPPTN/California Bell) (Out of service, March 2022)
- 806: 863-9999 Woodrow, Texas (South Plains Telephone Co-Op) (Out of service, March 2022)
- 812: 462-1218 Terre Haute, Indiana (Frontier North) (no answer, 2014)
- N-1-1 numbers
- These are mostly dead, except in rare locations where some of the standard information numbers (2-1-1 through 8-1-1) 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.
- 402: 311 Lincoln, Nebraska (Verified 2016)
- 410: 811 Annapolis/Baltimore, Maryland
- 419: 311 Toledo, Ohio
- 434: 311 Danville, Virginia (Verizon)
- 501: 511 Arkansas
- 503: 611 Portland, Oregon
- 515: 811 Des Moines, Iowa
- 540: 311 Roanoke, Virginia (GTE) (Verified 2016)
- 703: 811 Alexandria/Arlington/Roanoke, Virginia
- 713: 811 Humble, Texas
- 810: 311 Pontiac/Southfield/Troy, Michigan
- 907: 811 Alaska
- 908: 311-MMYY Northern New Jersey (Embarq, now CenturyTel) (MMYY is current Month/Year)
US toll-free
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.
- 1-800-444-4444 MCI ANAC (no input needed) (Verified January 25, 2022 from Raleigh NC) (not reachable from Canada)
- 1-800-437-7950 MCI ANAC (no input needed) (Verified January 25, 2022 from Raleigh NC) (Verified March 9, 2021 from Canada)
- 1-800-223-1104 PASSWORD-PROTECTED ANAC 195632 (Verified June 20, 2020)
- 1-855-343-2255 TracFone ANAC (press 1 for English) (January 25, 2022 from Raleigh NC)
- 1-855-227-3250 Consolidated Communications ANAC (January 25, 2022 from Raleigh NC)
- 1-877-521-2311 CenturyLink (Verified March 9, 2021 from US & Canada)
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.
- 1-800-225-5313 BANK OF SOUTH SIDE VIRGINIA, FRAUD DEPT (press 1) (Verified March 9, 2021 from US and Canada)
- 1-800-225-5214 NATIONAL CAPITAL BANK OF WASHINGTON, FRAUD DEPT (press 1) (Verified April 2018)
- 1-800-444-2222 MCI customer service (business) (Verified March 9, 2021 from US and Canada)
- 1-800-444-3333 MCI customer service (residential) (Verified March 9, 2021 from US and Canada)
- 1-800-314-4258, 1-800-444-0800, 1-800-444-4444, 1-800-950-5555 and 1-888-624-9266 (press 2 at prompt) are also often listed as MCI customer service.
- 1-800-660-2626, 1- 800-288-2020 AT&T Customer Service (Verified April 2018)
Canada
The current use of exchange prefixes for each area code is listed by CNAC;[8] 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 (dialled with any of the local area codes, as 10 digits) include:
- 555-0311 Rogers (403 Alberta, 519 613 Ontario)
- 958-2580 Bell Canada (519 613 416 705 905 Ontario, 450 418 438 514 579 581 819 873 Quebec)
- 958-6111 Telus landline (403 780 Alberta, 250 BC)
- 959-4444 Manitoba Telecom Services (204 MB) (959 is used since 958 is a regular Winnipeg exchange, not a test prefix)
- 958-9999 Bell Aliant (506 NB, 709 NL)
- 958-2222 Eastlink
These numbers are carrier specific and may be blocked from some individual payphones.
Additional plant test codes may be in use locally in some areas:
- 403: 555-0311 Alberta (GroupTel - may work in other parts of Canada - untested)
- 306: 958-1115 Saskatchewan (SaskTel - Bell 306 Mobility does not connect)
- 604: 1116 British Columbia (Telus)
- 604: 1211 British Columbia (Telus)
- 819: 959-1135 Most of Outaouais region (Bell Canada)
- 604: 827-2440 University of British Columbia
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:
- 403: 705-0311 Calgary, Alberta (Allstream - gives "call cannot be completed as dialled" in other parts of Canada, identifying as Allstream, active November 2019)
- 416: 477-0034 Toronto, Ontario (Fibernetics - Verified January 2021)
- 416: 477-0035 Toronto, Ontario (Fibernetics - verified January 2021; this number allows you to leave a message for reasons not yet determined)
- 416: 981-0001 Toronto, Ontario (verified July 2010) (busy, September 2015)
- 418: 380-0099 Quebec City (Vidéotron - verified 2017)
- 905: 310-3789 Mississauga, ON (Now no longer includes loop line or ringback. In NPAs where Bell Canada is incumbent, 310-xxxx is assigned as a pseudo-tollfree exchange which may be called at local call rates from an entire area code.)
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. 958-ANAC was in use by Bell Canada (416 Toronto) but looks to have been replaced by 416-958-2580. 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 the 555 exchange for other than the standard 555-1212 directory information line.
United Kingdom
- 17070, Openreach Linetest Facilities
- 020 8759 9036, same recording as 17070 but useful on LLU and cable lines where 17070's functionality is limited. Not usable on mobiles.
- 0808 170 7788, it does have a long introductory message, but it is useful on COCOTs which have 17070 barred.
- 18866, Same recording as 0808 170 7788 but a shorter number to remember.
- 020 8180 3803, Same recording as 0808 170 7788. These numbers are set up by a company offering low-charge calls in the UK, these numbers are meant to be used as a sort of operator routed through in order to qualify for these cheap calls. However, if the phone these numbers are dialled from is already registered with this company it will not announce the number.
Ireland
- 19 9000
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 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.
- 19 800 - International calls
- 19 822 - Local calls
- 19 801 - Calls to other parts of the Republic of Ireland, Irish mobile numbers and to landlines in Northern Ireland.
Israel
- *110 (Not working in all networks)
Australia
- 1800 801 920
- 127 22 123(Telstra landlines only)
New Zealand
- 1956 or 0 (8) 320-1231 area code and number
- 1957 or 0 (8) 320-1234 local number
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.
South Africa
- +27 21 405 9111 Cape Town ANAC
- +27 21 405 9116 Cape Town ANAC with callback
- +27 10 130 0999 Johannesburg ANAC
- +27 31 120 0999 Durban ANAC
- +27 87 180 0999 VoIP ANAC
- +27 84 190 0048 Mobile ANAC
See also
References
- ^ artofhacking.com List of local ANAC phone numbers in United States, Canada, Australia and Britain
- ^ "DSLreports: Identifying the telephone number of an ADSL dry loop (Canada)".
- ^ "Maintaining / Phreaking modems lines using ANAC numbers". Archived from the original on 2003-09-30.
- ^ alt.2600 FAQ, rev 0.14, part 2 of 4 (2000/05/29) is the most common list, hopelessly out of date.
- ^ a b "Testing.HTM". pages.furmannet.net. Archived from the original on 19 December 2013. Retrieved 15 January 2022.
- ^ NANPA report of Colorado codes in use or reserved by area code
- ^ NANPA list of available/unassigned Colorado codes by area code
- ^ "CO codes (list of all exchanges in each area code, including test and reserved prefixes)". Canadian Numbering Administrator.