PURPOSE: To inform a cause to disabled connection to a user by monitoring a signal tone sent from a communication network while a line switching signal from the communication network after automatic origination and outputting a signal tone as voice when the signal tone is sent.

CONSTITUTION: A control section 10 receiving the end of transmission of an information center number starts a signal detection circuit 5 and a timer monitoring circuit 7 monitors the time of videotex switching instructing signal for a prescribed time. Simultaneously, the control section 10 opens a speaker device 8 so as to output a signal tone sent from the videotex communication network. When a signal tone other than a line switching signal is sent till the line switching signal from the network is received in the case of the connection to the information center via the communication network through automatic origination while the communication network is faulty or the service is stopped or the like, the control section 10 outputs the signal tone as a voice signal. Thus, the cause to disabled connection is recognized by the user even at automatic origination.