| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for retrieving a base station by which a system to which a slave set is connected is automatically switched just after the slave set detects that it is out of zone, the current consumption is reduced and the operating time of the slave set can be extended. SOLUTION: A radio section of a slave set 10 receives a signal sent from a radio base station A201 connected to a public system, or a master set 203 connected to a radio base station B202 or a private system, and the slave set 10 detects that it moves to the outside of a range 204 where connection to the radio base station A201 is available, to the outside of a range 205 where connection to the radio base station B202 is available, or to the outside of a range 206 where connection to the master set 203 is available from a standby state on the basis of the received data and a received electric field strength, the slave set 10 retrieves control carriers of both a system having awaited so far and another system just after the detection that the slave set 10 is out of the above zones and automatically selects a system without retrieving the control carrier of the radio base station A201, the radio base station B202 and the master set 203 at all times. |
