| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of howling by improving accuracy in detecting a shield existent in the vicinity even under any situation for a transmitter/receiver being occupied. SOLUTION: The present invention relates to a telephone apparatus 10 comprising a transmission interface circuit 101 for transmitting/receiving a transmission/reception voice signal; a receiver circuit 102 for outputting a reception voice; and a transmitter circuit 103 for collecting transmission voices. The telephone apparatus 10 further includes: a light-emitting element 104 emitting light; an emission circuit 106 for causing the light-emitting element to emit light in a prescribed emission pattern; a light-receiving element 105 for converting sensed light into an electric signal and outputting it; a light-receiving circuit 107 for detecting, from the electric signal output by the light-receiving element, an electric signal obtained by converting light, in the prescribed emission pattern emitted from the light-emitting element; and a transmission signal control circuit 108 for outputting to the transmission interface circuit a transmission stop signal for disconnecting the transmission voices from a communication line immediately when the prescribed electric signal is detected by the light-receiving circuit. COPYRIGHT: (C)2010,JPO&INPIT
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