| 摘要 |
PURPOSE:To realize a function as a cordless telephone set by increasing an electric field criterion level of a radio channel in response to the environment of location where the cordless telephone set is installed up to a range not in excess of the upper limit stipulated by the regulation to avoid the effect of external noise. CONSTITUTION:A master set 100 and a cordless telephone set 200 are provided respectively with electric field level discrimination sections 105, 205 to set plural discrimination levels of the presence of a carrier and with terminals such as 0dBmu, 3dBmu, 6dBmu for each electric field level. For example, when two stages of terminals as 3dBmu, 6dBmu are provided, the level is set at factory shipping and carrier sense is implemented by, e.g. a level of 3dBmu dust after power application and when it is discriminated to be the presence of a carrier due to external noise or the like within a regulated time (such as 1sec or over), the carrier criterion is revised into the 6dBmu level, then the carrier sense is executed again, and when absence of carrier is discriminated in this case, it is regarded that the radio channel is available to permit incoming and outgoing communication. Thus, the call loss is reduced. |
