Feature group

A '''feature group''', in North American telephone industry jargon, is most commonly used to designate various standard means of access by callers to competitive long-distance services. They defined switching arrangements from local exchange carriers central offices to interexchange carriers. These arrangements were described in Tariff No. 5 of the National Exchange Carrier Association, filed on 25 October, 1991 with the Federal Communications Commission (FCC).<ref>{{cite web |title=National Exchange Carrier Association, Inc. (NECA) Tariff F.C.C. No. 5 |url=https://www.fcc.gov/document/national-exchange-carrier-association-inc-neca-tariff-fcc |website=FCC.gov |publisher=Federal Communications Commission |access-date=7 February 2026}}</ref>

==Feature groups==

While there are other feature groups for local access,<ref>[http://www.stuffsoftware.com/features.html Complete List of NECA standard Feature Codes]</ref> the four common feature groups exist for access from the local subscriber to competitive long-distance carriers.

===Feature Group A===

The original implementation, in which a user has to dial the local telephone number of a provider's gateway, followed by (usually) a password, then the desired long-distance number. There is a different local access number in each local calling area. This requires no special capability at the local telephone company office as competing long-distance providers connected using standard local lines, which may or may not support caller ID. If a carrier has no local presence, a foreign exchange line is used to reach its nearest point of presence.<ref>[http://wholesale.att.com/products_and_services/access/transport/SWA_FGA.html Feature group 'A'] {{Webarchive|url=https://web.archive.org/web/20120722061425/http://wholesale.att.com/products_and_services/access/transport/SWA_FGA.html |date=2012-07-22 }}, AT&T/SBC</ref> Once the standard means of accessing alternate long-distance carriers, local access numbers are now used primarily for low-cost prepaid calling cards as the calls may be made from any phone, at flat or local rates.

===Feature Group B===

Associated with 950-XXXX calling; instead of a local telephone number the user enters 950 and 4 additional digits which identify the long-distance carrier. Operation is similar to the local access numbers (feature group A) except that the 950-XXXX access number is the same in every community, NANP-wide.<ref>[http://wholesale.att.com/products_and_services/access/transport/SWA_FGB.html Feature group 'B'] {{Webarchive|url=https://web.archive.org/web/20120722061334/http://wholesale.att.com/products_and_services/access/transport/SWA_FGB.html |date=2012-07-22 }}, AT&T/SBC</ref> Some exchanges send the caller's number automatically; where this service is not provided or not desired (calling card applications), the 950-XXXX number must be followed by a calling card number and the long-distance destination number. If ANI is provided, calls from the one subscribed line may be made as 950-XXXX and the long-distance destination. Largely deprecated by feature group D, but the 950 prefix and a list of carrier codes<ref>[http://www.nanpa.com/enas/formCICBMasterReport.do NANPA list of feature group 'B' carrier codes]</ref> remain reserved in all North American area codes, even in Canada where most providers went from feature group A directly to 1+ default carrier dialling and feature group D (101xxxx + destination) calling without ever using 950-XXXX as a primary means to access alternate long-distance carriers from home land lines.

===Feature Group C=== Rare, originally used by AT&T for operator-assisted coin phones since they allow the operator to keep control of the caller's telephone line until the transaction is completed.<ref>[http://www.phworld.org/payphone/acts.htm Telephone World - AT&T Automated Coin Toll System]</ref> As coin-handling for trunk calls is now automated within the phone (like a COCOT, the current generation of coin phones operates self-contained without the central exchange providing coin-call support functions), group 'C' is largely obsolete.

===Feature Group D===

The current standard, requires the local switch support equal access by competing carriers at the trunk level; highest quality connection, and allows pre-selection of the interexchange carrier by the end-user. This feature group permits two types of calls. If a user dials 1 + area code + seven-digit number, the long-distance call is handled by a default carrier chosen by the user. Alternatively, a user dials 101 + four-digit carrier code + area code + seven-digit number, and the call is handled by the carrier specified by the carrier code.<ref>[http://wholesale.att.com/products_and_services/access/transport/SWA_FGD.html Feature group 'D'] {{Webarchive|url=https://web.archive.org/web/20120722061320/http://wholesale.att.com/products_and_services/access/transport/SWA_FGD.html |date=2012-07-22 }}, AT&T/SBC</ref> The original batch of carrier codes were three-digit, and began with dialing 10; when eventual exhaust became apparent, the instructions changed to represent it as "dial-around" 1010-xxx service; after an extended permissive period, 10+xxx ceased to function, and now functions as 101+xxxx, with the second zero migrated to turn the original three-digit codes into four-digit codes starting with zero; new codes were assigned with other numbers as the first of four digits. NANPA maintains separate lists of carrier codes for feature groups 'B' and 'D'<ref>[http://www.nanpa.com/enas/formCICDMasterReport.do NANPA list of feature group 'D' carrier codes]</ref> as not all long-distance providers support both standards.

These alternative groups allowed the LEC's end users to make long-distance calls using the interexchange carrier's network, when non-stored program-controlled exchanges could not be modified to provide equal access. By the mid 1990s, Equal Access features in exchange software had rendered Feature Group D universally available in modern landline exchanges; the others are either used for calling card applications or are obsolete.

==References== {{reflist}}

{{DEFAULTSORT:Feature Group}} Category:Telephone services Category:Telephone service enhanced features Category:United States communications regulation