| 摘要 |
PROBLEM TO BE SOLVED: To execute communication with the infrared ray output of necessary minimum limits in spite of a facing device by using infrared-ray transmission output when a station detection command from which a station detection response is returned from a secondary station is transmitted among plural transmitted station detection commands obtained by changing infrared ray transmission output. SOLUTION: When infrared ray data is not received for 500 m s, a portable telephone set 3 transmits a station detection command for the number of slot times, which is previously set from a slot number (1) at a constant time interval. When a station detection response cannot be received, CPU 11 gives an instruction to a resistance controller 19 and reduces the resistance value of a variable resistor 18 which is in a light emitting element 17 in series by a value which is set. A transmission output level is raised and the station detection command is transmitted again by the number of slot times, which is previously set. When it is repeated until the station detection response can be received, current consumed in the light emitting element 17 can be suppressed to a minimum in a range where infrared communication can normally be executed. |
