在1979年世界电信博览会上,某公司首次展出了一种无线电话接收机。接收机自成单元,它与电话和电话网络的联接通过红外光路进行,不用导线。这种红外电话主要由一台普通电话机、一个壁挂的固定部分、光/电流转换器和这种接收机组成。全部控制钮都装置在接收机里,以便打电话的人能带着接收机自由地在房间里活动,在固定部分与接收机之间的一切控制脉冲和谈话是通过红外线来传送的。这种传输方法能使传播限制在电话所在房间内进行。因此,不影响具 At World Telecommunication Expo 1979, a company exhibited for the first time a radiotelephone receiver. The receiver is self-contained, and its connection to the telephone and telephone networks is through the infrared path without wires. This type of infrared phone mainly consists of an ordinary telephone, a wall-mounted fixed part, a light / current converter and such a receiver. All controls are housed in the receiver so that the person making the call can move freely in the room with the receiver and all control pulses and talk between the fixed part and the receiver are transmitted by infrared. This method of transmission limits the transmission to the room in which the telephone is located. Therefore, it does not affect