Foreign exchange service

In telecommunication, a foreign exchange service (FX) is a network-provided service in which a telephone in a given local exchange[?] area is connected, via a private line, to a central office in another, i.e., "foreign", exchange, rather than the local exchange area[?]'s central office.

Note: To call originators, it appears that the subscriber having the FX service is located in the foreign exchange area.

Source: from Federal Standard 1037C