READER/WRITER AND AUTHENTICATION SYSTEM USING THE READER/WRITER

摘要

According to a structure of a mobile terminal inserted, it is possible to change a threshold value of a reception intensity which judges that a reception signal is present and a transmission output when outputting a signal. An authentication system receives a response signal (SIG402) containing a reception intensity value of an authentication level setting signal (SIG401) and a response signal (SIG404) containing a reception intensity value of the authentication level setting signal (SIG403) and compares the reception intensity value of the authentication level setting signal (SIG401) and the reception intensity value of the authentication level setting signal (SIG403) so as to store the greater reception intensity value (X). The system identifies an antenna (antenna P) used when the reception intensity value (X) is obtained and decides an antenna to be used for transmitting the signal from a reader/writer (150) in the authentication phase.