| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform highly confidential information communication in simple configuration. <P>SOLUTION: A master unit 2 radiates a decryption code as an optical signal in each set timing. A slave unit 3 disposed within a radio communication area wherein the optical signal can be received, receives the decryption code and stores it in a built-in storage section. When transmitting information by radio communication using radio waves, the slave unit 3 adds the decryption code to transmission information and performs radio transmission of the information. Furthermore, the slave unit 3 is configured to utilize the decryption code to decrypt the information received by the radio waves. Slave units 3 within the radio communication area of the same master unit are capable of perform radio communication of information due to radio waves with each other by utilizing the decryption codes provided from the master unit 2 by optical radio communication. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
