电话机是电话通信系统中的一个终端设备,它和电话线路、交换机共同构成电话通信系统。在这个系统中,上述三个部分不论哪一部分工作失常,通话都将中断。因此,电话出现故障时首先应确定出故障范围,出在交换机和外线上,还是出在电话机,然后才能根据故障范围决定是通知故障台查修线 Telephone is a terminal equipment in the telephone communication system, which together with the telephone lines, switches constitute a telephone communication system. In this system, no matter what part of the above three parts work abnormally, the call will be interrupted. Therefore, the phone failure should first determine the fault range, the switchboard and the outside line, or in the telephone, and then can be determined according to the fault range is to notify the fault line inspection line