电话用作防盗监听顾平和家中无人时，可以利用电话作防盗监听，仅需附加一套控制线路，离家时用开关和电话外线接通，在任何地点，用该地电话，能随时监听一下家中电话机周围的声响动静，判断有无他人入侵，或其他异常情况发生。图１是外线供电型控制电路原理：当您需要监... Telephone for anti-theft monitoring Gu Ping and no one at home, you can use the phone for anti-theft monitoring, only an additional set of control lines, leaving home with the switch and the phone connected outside, anywhere in the use of the phone, can monitor at any time Look around the sound of the phone at home to determine whether there is any invasion of others, or other anomalies. Figure 1 is the external power supply type control circuit principle: when you need to monitor ...