A communication apparatus comprises a modem configured to performed FAX communication, and a connection unit configured to connect a telephone apparatus. The communication apparatus detects a CNG signal, and controls, in a case where there is an incoming call in a state in which FAX communication is being performed by the modem, if the CNG signal is not detected in the detecting, so that a signal is supplied from a line to the telephone apparatus, and controls, in a case where there is an incoming call in a state in which FAX communication is not being performed by the modem, if the CNG signal is detected in the detecting, so that FAX communication by the modem is initiated.