DEVICE AND METHOD FOR AUTHENTICATION OF TRANSMISSION SOURCE

PROBLEM TO BE SOLVED: To guarantee a conventional operating style and to block illegal access by providing a calculation part for outputting a signal for setting a flag when a prescribed value is counted by the output of a password collation part and a connection control part for controlling the start of communication with the transmission source. SOLUTION: A password collation part 5 collates a received password(PW) and a PW 4-2 registered in a registration part 4. In the case of non-coincidence as a result, a step signal is outputted to a count part 6, and a reception part 1 waits the re-reception of transmission source recognition data. Each time there is an output from the password collation part 5, the count part 6 is stepped by '1' and when the prescribed value is counted, a relevant (f) 4-4 in the registration part 4 is set by its output. A connection control part 7 recognizes the state of that (f),4-4 and when it is set to ON, the presence of access caused by an incoorrect PW is reported to the transmission source. Then, the flag is reset to OFF and the following regular communication procedure is executed.