| 摘要 |
PURPOSE:To provide a cordless telephone system which can restart the talking even if the battery power supply contained in a slave device is cut off in a busy mode as long as the cut-off power supply is restored. CONSTITUTION:A slave device 10 includes a back-up power supply 30 which backs up a RAM 18. When the bidirectional communication is set up between the device 10 and a master device 20 via a pair of radio channels, a microcomputer 16 contained in the device 10 writes the data into a prescribed memory area of the RAM 18 to show the connection of a channel. When the transmission is stopped at the side of the device 10 in a busy mode due to the opening of the contact of a replaceable battery 19, a microcomputer 26 of the device 20 transmits an out-range signal. When the battery 19 is connected again in the device 10, a transmission/reception circuit 12 of the device 10 starts a receiving action as long as the channel connection data are written in the RAM 18. Receiving the out-range signal from the device 20, the circuit 12 also restarts a transmitting action. |
