电话机摘机后,听筒完全无声,工作指示灯不亮,此时用户通常都会断定是电话线路短路或断路了,而对于一些较特殊的故障现象,诸如:电话机振铃一声后即断线:电话机振铃正常,但不能拨号或通话:电话杂声大等故障,用户往往会怀疑电话机有毛病,便去更换一台新的电话机,但故障依旧,这时就确定问题是在电话线路上了。其实这类故障大多发生在用户电话机附 After the phone is off-hook, the handset is completely silent and the work indicator is off. In this case, the user usually concludes that the phone line is short-circuited or open. For some special problems, such as: : The telephone ringing normally, but can not dial or call: telephone noise and other major problems, the user often suspects the telephone is defective, then to replace a new telephone, but the fault still, then determine the problem is on the phone The line is up. In fact, most of these failures occurred in the user’s phone attached