| 摘要 |
A cordless telephone provided with a master unit and a slave unit which use a plurality of communication channels. In the case where information indicating a currently used channel or a usually used channel, which has been stored in the master unit, is lost due to, for instance, a power failure, the master unit comes to use an initially used channel, which is preset or determined by performing an operation on an identification code, and enters a standby state. At that time, the slave unit uses the usually used channel. However, when it is detected that the slave unit cannot communicate with the master unit, the slave unit calls the master unit by using the initially used channel. Then, the master and slave units come to perform, for example, an exchange of confirmation data by using the initially used channel. Next, the slave unit transmits to the master unit data indicating that the channel used by the master unit should be changed to the usually used channel. In response to the data, the master unit made to use the usually used channel. Consequently, both of the master and slave units come to use the usually used channel and are able to communicate with each other. Thus, the cordless telephone does not require another power source for a backup circuit. Further, the circuit configuration of the cordless telephone becomes simple.
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