A communication apparatus includes a first detection circuit which detects a
call
signal, and a second detection circuit detects information of a partner station
sent between call signals. A memory circuit stores information of a communication
system of the partner station in association with the information of the partner
station. A reading circuit reads the information of the communication system for
the detected information of the partner station from the memory circuit in accordance
with the information of the partner station detected by the second detection circuit
at the time of the detection of the call signal and executes the communication
protocol in accordance with the read information of the communication system.
