| 摘要 |
PROBLEM TO BE SOLVED: To reliably display messages such as advertisement on personal portable telephones without calling individual portable telephones from a distributor. SOLUTION: The data communication system is composed of radio base stations 14 and 15 which are connected to access points 11-13 through direct lines, public lines and an ISDN network, a portable telephone 16 which is connected to the network by radio through the radio base stations 14 and 15 and performs data communication by using error control and a terminal 17 which is connected to the network by using the data communication function of the portable telephone 16 and performs data communication. During data communication, an error frame whose CRC code as an error detecting code is changed by specific operations and is transmitted as a massage frame. The portable telephone 16, upon detection of the massage frame, fetches and stores the data contained in the message, displays the stored data as character information or image information on the screen and outputs voice information from a sound source.
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