PURPOSE: To prevent remote control by a suspicious person by limiting a remote control of incoming call by the use of a password ID in an ISDN terminal adapter.

CONSTITUTION: At the time of the incoming call from a remote terminal, a connection message is transmits to a network 101 from a call control part 5 and a call is once disconnected. Moreover, a call originator transmits the password ID which is registered in an ID registering part 11 from a transmitting part 10 by adding it to a call setting message. In an incoming call side device, an ID receiving part 9 takes out the password ID from the received message, compares it with a self ID which is set in the ID registering part 11, connects the call at the time of coincidence and changes-over communication data path from 1) to 2). At the time of noncoincidence, the call is disconnected.