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A Feature Group is United States telephone industry jargon for four types of access to long distance service. They defined switching arrangements between Local exchange carriers central offices to interexchange carriers.
Four feature groups exist:
- Feature Group A - user has to dial a local telephone number, following by the desired long-distance number.
- Feature Group B - associated with 950-XXXX calling; instead of a local telephone number the user enters 950 and 4 additional digits; depending on the service provided this may be followed by a calling card number and the long-distance number
- Feature Group C - used mainly by AT&T for pay phones since they allow the operator to keep control of the caller's telephone line until the transaction is completed
- Feature Group D - highest quality connection, and allows pre-selection of the interexchange carrier by the end-user. This feature group permitted 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. Most carrier codes began with 0, so this type of "dial around" service was typically marketed as dial-around 1010 service.
These Feature Group alternatives 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. Late in the 20th century,[when?] Equal Access features in exchange software rendered Feature Group D universally available.