| 摘要 |
PROBLEM TO BE SOLVED: To reduce a current consumption for searching a radio base station of a portable telephone set communicable in a plurality of frequency bands. SOLUTION: Within a range 302 connectable to a radio base station 301, a portable telephone set 10 performs transmission/reception with the radio base station 301 in a frequency band wherein the radio base station 301 provides services. When the portable telephone set 10 moves to 10a within an unconnectable range 303 just after getting out of the connectable range 302, an out-of-circuit status is provided but a waitable received field value is not reduced so much in this range, so that just after the out-of-circuit state is detected, a radio base station is searched by channel scanning only in one frequency band that is waited just before. When a system number that is waited before, is not present even after the radio base station is searched, the radio base station is searched in each of a plurality of frequency bands. COPYRIGHT: (C)2005,JPO&NCIPI
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