Definition of outside line in English:
A telephone connection with an external exchange.
- A private branch exchange is a private telephone network used within an enterprise in which users share a certain number of outside lines for external telephone calls.
- For the first time since the telephone was invented, one worker could call another inside the company, as well as connect to an outside line without any operator assistance whatsoever.
- The green telephone, the outside line, rang at five past twelve.
Definition of outside line in:
- US English dictionary