| 摘要 |
PURPOSE:To continue excellent communication at all times, by selecting an idle channel from a cordless telephone set or a master device automatically and starting communication immediately in using plural radio channels for cordless telephone sets more than the number of channels in common, and selecting the other channel automatically with the detection of electrogmagentic wave interference. CONSTITUTION:In starting a call, electromagnetic waves 21 of one of common channels are transmitted from a transmission section of a calling device via a transmission antenna, the waves are received at a reception section via a reception antenna of the device, and electromagnetic waves transmitted from the other devices are received at a reception section 2. The result of reception is led to an idle channel detecting means 14, a beat signal 22 is detected and the amplitude A is measured, and when the amplitude A is a prescribed value or below, it is discriminated that the frequency during transmission is the idle channel. Since it is discriminated that the frequency is used in the other devices when the amplitude A is measured and it exceeds the prescribed value, a channel switching means 13 is operated, a preset value is inputted to a divider 12 and the next channel is generated at a synthesizer 13. |
