人们在下雨天打电话的时候,经常发现电话出现串音,干扰了正常通话。有的人以为是电话机出了毛病,其实不是,问题多半出在市话电缆上。市话电缆是连接各电话用户与电话总机之间的线路,它是由芯线、绝缘材料和保护层三部分组成。同一条电缆内芯线数量虽然成十上百,但在正常情况下,相互之 When people make phone calls on a rainy day, they frequently find crosstalk in the phone and interfere with normal calls. Some people think that the phone is out of order, in fact, not the problem most of the local telephone cable. Local telephone cable is connected between each telephone user and telephone exchange line, which is composed of core wire, insulation and protective layer of three parts. Although the number of cores in the same cable into the hundreds, but under normal circumstances, each other