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本装置可对故障电话的发号、通话、振铃电路进行检测分析,且可以使两台电话机互相通话。工作原理如图1,220V交流电经B1变压输出双36V交流电压,分两路;一路经C2、R2给电话提供36V交流振铃信号,C2、R2起限流作用,以防止摘机后振铃信号损坏电话的通话和发号电路。另一路经D1、D2、C1整流滤波,R1限流,L的信号隔离,给电话提供挂机时的48V直流电压和摘机后的8V左右的工作电压。两路电压通过AN转换,接到电话的线路输入端,LED起发号指示作用,信号接口通过B2、C3、C4隔离,既是音频信号的输入接口又是音频信号的输出接口。元件选择 B1用220V/5W变压器改制,保留初级线圈,拆去次级线圈,改用0.15漆包线绕600×2匝。L用收音机小变压器改制;拆去铁芯和所有线圈,用0.15漆包线绕500匝,装上铁芯即可。B2用收音机输出变压器直接使用,其它元件无特殊要求,器件具体数值见图1。
The device can detect the fault number, call, ringing circuit analysis, and can make two phones talk to each other. The working principle is as shown in Figure 1,220V AC by the B1 transformer output dual 36V AC voltage, in two ways; all the way through the C2, R2 36V AC ringing signal to the phone, C2, R2 from the current limit to prevent off-hook ring Signal corrupted phone call and numbering circuit. Another way D1, D2, C1 rectifier filter, R1 current limit, L signal isolation, to the phone to provide on-hook 48V DC voltage and off-hook after about 8V operating voltage. Two voltage through the AN conversion, received the line input of the phone, LED from the issue of instructions, the signal interface through B2, C3, C4 isolation, both audio signal input interface and audio signal output interface. Component selection B1 with 220V / 5W transformer restructuring, retaining the primary coil, remove the secondary coil, switch to 0.15 enameled wire around 600 × 2 turns. L small transformers with a radio system; remove the core and all coils, with 0.15 enameled wire around 500 turns, can be loaded on the core. B2 radio output transformer direct use, no other special requirements components, the specific value of the device shown in Figure 1.