| 摘要 |
PROBLEM TO BE SOLVED: To prevent the execution of outer alarm in an unnecessary place by providing a means for setting radio transmission power and a means for executing outer alarm in accordance with the radio transmission power. SOLUTION: The control circuit of a master set obtains a reception electric field strength value at every subscribed interval (at every second, for example) by AD conversion in a call state. When obtained electric field strength is continuously below a reference level for subscribed time (five seconds, for example) and present radio transmission power is weak, radio transmission power from a tuner is turned to strong and a strong radio transmission power instructing command is transmitted to a slave set. When the radio transmission power instructing command is received from the master set, the control circuit 25 of the slave set makes radio transmission power strong when the instruction is strong and makes it weak when the instruction is not strong. The AD conversion of electric field strength from the master set is executed by prescribed interval (at every second, for example) and outer alarm is executed when electric wave transmission power strength from the present master set tuner is strong and an obtained value is below the reference level. |
