the part of a public telephone network in which connections are established as and when required
public telephone network - a telephone network supplied, operated, and controlled by a telecommunication operating administration or recognized private operating agency, in order to provide a public service
... in reply to the Portuguese authorities' argument that mobile operators will reduce Portugal Telecom's international traffic, that it is highly unlikely that users (most of whom are business users) will use their GSM in place of the PSTN for international calls ...
