direct distance dialling (DDD)

The older term self-dialing long-distance service (SWFD) refers to public telephone service over the public switched telephone network in which a connection is made by entering the number directly on the telephone. The term self-dialing long distance service dates back to the days of hand-switched or semi-automatic call transfer. With this telephone service, the dialing subscriber can establish any connections with other subscribers of another carrier, this also applies to international connections.