|456||International inbound 56K data (for ISDN use) (discontinued) [*]|
|600||Canadian non-geographic services, including caller-pays cellular (within Canada only)|
|622||Canadian non-geographic services (expansion of 600) (within Canada only)|
|700||Carrier-specific services (generally not toll-free)|
|710||U.S. Federal Government (authorized users only)|
|(822)||future toll-free (implementation not yet scheduled)|
|880||Paid international calls to +1 800 (discontinued)|
|881||Paid international calls to +1 888 (discontinued)|
|882||Paid international calls to +1 877 (discontinued)|
Toll-free services are essentially automated collect calls. The recipient of the call pays the cost. However, many toll-free numbers only work within a limited subset of the North American Numbering Plan countries (for example, only the U.S.A., or only the U.S. and Canada), so “replace” codes were implemented for the first three toll-free codes: 800, 888, and 877. To dial a U.S.‑only 877 number from another NANP country, a caller might dial 1‑882‑nxx‑xxxx. The caller paid the same international call charge as for a standard call to the United States. These codes could also be used for calls originating outside the NANP. However, the use of the 880/881/882 codes was discontinued as of 2004‑04‑01. The original toll-free 800 code has been expanded to 888, 877, 866, 855, 844, and now 833 (as of 2017‑06‑03). The next codes added will be 822 and then the remaining 88X codes.
International inbound 56K data calls required a special code because normal international calls may be routed to any North American carrier at the convenience of the originating country’s telco. A randomly selected carrier in North America may not provide appropriate facilities for terminating a high-speed data link. Thus, calls to the 456 area code were routed to a specific carrier based on the number dialed. This code was not used for domestic calls, but was used for international calls within the NANP. However, due to declining use of this resource — primarily because data links over the Internet are easier, faster, and much less expensive (although less secure) than ISDN data calls — area code 456 was discontinued in 2017. 456 will be available for reassignment as a general-purpose NPA in 2023.
Information services provide some form of content for a charge over and above the cost of the telephone connection itself. Many information services provide sexually explicit adult content, but there are other uses, such as per-incident telephone technical support for computer software, automated donations to charitable organizations, psychic / astrological / Tarot readings, stock quotes, and allegedly lucky lottery numbers.
Carrier-specific numbers may be used for almost any purpose a long-distance carrier may devise. There were some carriers in some areas of the U.S. who used 700 as a replace code for the caller’s own area code, in order to route intra-LATA toll calls on the long-distance carrier instead of the local “Baby Bell”; however, that practice is discouraged, since it is now possible to presubscribe intra-LATA toll calls to your long-distance carrier. Some carriers use some 700 numbers for information services at charges comparable to 900 numbers. Other carriers use 700 numbers for purposes carrying more modest price tags. Almost all carriers use 1‑700‑555‑4141 to verify the caller’s default long-distance carrier for inter-LATA calls. Many areas use 1‑NPA‑700‑4141 to verify the intra-LATA toll carrier, where “NPA” is the caller’s own area code; however, you should check with your telephone company, since 700‑4141 may also be an ordinary number in your area code.
Non-geographic Services: Originally, area code 500 was intended to be used for “Personal Communications Services” (a.k.a. “the Other PCS”), which in this context refers not to cellular telephones, but rather to so-called “follow-me” numbers. The idea was to have a single number, say (500) 123‑4567, that you could program to ring your home phone from 6 to 10 p.m., go directly to voicemail at night, and ring your desk at work during the day. The number could also have some sort of response menu, along the lines of “press 1 for voicemail, 2 for fax, 3 for cellphone.” Some implementations also allowed the same 500 number to be used for caller-pays or called-party-pays: dialing 1‑500‑xxx‑xxxx, the caller would pay the cost of the call, but dialing 0‑500‑xxx‑xxxx, the caller could enter a 4-digit PIN to charge the call to the owner of the number. However, in spite of efforts to keep telesleaze out of the 500 number space, some unscrupulous operators exploited a feature that allowed 500 numbers to forward internationally, with the additional charge borne by the caller with only a “press 1 to accept” warning, if that.
“Follow-me” numbers never really caught on, so the numbering space (including expansion codes 521, 522, 523, 533, 544, 566, 577, and 588) is now used primarily for purposes that require a telephone number but that do not require a number associated with a specific geographic location. In fact, most of these numbers are not dialable on the public telephone network. One example is devices such as iPads equipped to use a cellular data network. For billing purposes, there needs to be a unique number associated with the iPad, even though that number cannot be used for inbound calls to the device. Home alarm systems that connect to a wireless carrier would also qualify. There are also other devices that may not use the phone network at all, but for some reason need a non-geographic telephone number as an address. Area codes 511, 555, and 599 are reserved, so, now that the 522 code has filled up, miscellaneous unused 5XX codes will be used, beginning with 521 and 523 through 529. Area code 523 went into effect 2018‑11‑12. (Note that 520 is an ordinary geographic area code for Tucson, Arizona.)
The 600 code is used for non-geographic services exclusively in Canada. One purpose for which 600 numbers are used is caller-pays cellular, as well as purposes similar to the 5YY codes in the United States. Area code 622 is an expansion of 600, for the same purposes, with 633 reserved for future use. L’indicatif 600 s’utilise pour certains services non-géographiques exclusivement au Canada, y compris le service cellulaire avec paiement par l’appelant, et aussi les fins similaires à celles utilisées par les indicatifs 5YY. L’indicatif 622 est une extension de 600, aux mêmes fins, et 633 est réservé pour l’utilisation future.
The 710 code is used by the U.S. Federal Government for official emergency purposes. Very little specific information is publicly available.
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Last updated 2018-11-29.
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