Intelecommunications, a call is a switched connection between two or more communication partners: the calling party and the called party. With the call, dial tones and/or ring tones are transmitted to the exchanges for the purpose of switching a communication connection.
The communication connection can be established as a voice connection or data connection between two or more terminal devices. Between the subscriber initiating the call with its transmitting terminal equipment and the receiving equipment. A call thus requires signaling to trigger the establishment of the connection. Only when this has taken place and the connection has been established can communication between the terminal devices take place. The signaling procedure can be triggered manually or automatically and depends on the type of signaling and the signaling system.