These devices are designed to limit overvoltages on the telephone line.Overvoltages are normally caused by a.c.power sys
问题描述：
These devices are designed to limit overvoltages on the telephone line.Overvoltages are normally caused by a.c.power system or lightning flash disturbances which are induced or conducted on to the telephone line.A single device provides 2-point protection and is typically used for the protection of 2-wire telecommunication equipment (e.g.between the Ring and Tip wires for telephones and modems).
答
这些装置的目的是限制过电压的电话线路.过电压一般造成的交流电源系统或雷电干扰诱导或进行的电话线.一个设备提供2点保护与通常用于保护双线通信设备（如环和尖端电线电话和调制解调器）.