MODEM, COMMUNICATION CONTROLLER AND COMMUNICATION CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To surely prevent a controller main body from reaching a loop state by allowing the controller to be adaptive to a communication protocol in compliance with an optional recommendation. SOLUTION: A variable signal detection section 105 detects a protocol signal sent from a caller side in a signal received by a reception section 103, while a transmission section 104 sending the protocol signal in compliance with a prescribed recommendation is transmitting a DIS signal stipulated by the recommendation T.30 or after sending the DIS signal. When the protocol signal is a CM signal in compliance with the recommendation V.8, the controller transits to a communication operation in compliance with the recommendation V.8 and when the protocol signal is a signal used for data communication, the controller transits to a data communication operation.