碰到有交流杂音的电话机 ,可用此话机拨叫另一台好的话机。振铃后被叫摘机 ,听到交流杂音信号后 ,将故障话机的手柄四芯曲线拔掉。如交流杂音消失 ,可判定是由驻极体送话器损坏引起。有时驻极体送话器并没有损坏 ,只是其负极(接地端 )与其外壳接触点虚接引起。只要将手柄拆开 , Encountered a noise of the phone, you can use this phone to dial another good phone. After being ringing, the called party picks up the phone and after hearing the AC noise signal, unplug the four-core curve of the handle of the faulty phone. Such as the disappearance of acoustics, can be judged by the electret microphone damage caused. Sometimes the electret microphone is not damaged, but its negative (ground) and its shell contact point caused by virtual connection. As long as the handle apart,