| 摘要 |
<p>The user who wants to receive a service calls a center (3) of the service by using an ordinary telephone set (2) in the user's home or office. The user directs a loudspeaker provided on an authentication card (10) toward a transmitter of the telephone set (2), depresses instruction buttons on the authentication card (10) in accordance with the guide given by the center (3), and identification tone of the same card is outputted from the loudspeaker. Since this identification tone is audible, it is received by the center (3) from the transmitter of the telephone (2) via a telephone line (4) and used for the authentication of the user.</p> |
