Intercom vs. Entryphone — What's the Difference?

An intercom ("intercommunication device") or interphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles.

An intercom system which enables someone, without opening the door, to converse with the person who has rung the doorbell.

An electronic intercommunication system, as between two rooms.

An electronic communication system, especially one between rooms in a building.

(ambitransitive) To communicate (with) by intercom.

A communication system linking different rooms within a building or ship etc