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话王牌TPT—200A型电话防盗器是邮电部批准入网的电话防盗产品。笔者根据实物测绘出了该电话防盗器的电路原理图(如图1),并对其常见故障的检修方法进行分析与介绍,供修理人员在检修时参考借鉴。一、电话原理简介当主机1、2均处于挂机状态时,外线送来的48V工作电压经过电阻R1—R3的分压,使三极管Q1饱和导
If the trump card TPT-200A phone alarm is approved by the Ministry of Posts and Telecommunications network security products. I based on the physical mapping out the circuit diagram of the telephone alarm (Figure 1), and its common troubleshooting methods for analysis and introduction for the repair staff reference for reference in the overhaul. First, the phone principle Introduction When the host 1, 2 are in on-hook state, the outside sent 48V operating voltage through the resistor R1-R3 partial pressure so that the transistor Q1 saturation guide