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电话防盗打电路很多,大都是对并线盗打者有效。如果盗打者将电话线剪断或在电话局将线从接线端子上拿下来,用户的电话线甩掉后再打,打完再接上,在这种情况下并线式电话防盗器就无能为力了。 笔者设计并试验成功一种电话断线盗打报警器电路。这种报警器能在断线盗打的情况下发出短时的声音报警(如语言报警抓小偷,或其他类型)、长时间的灯光报警,并能记录开始盗打时间
Telephone anti-theft circuit a lot, mostly effective against parallel pilferers. If the rogue behear the telephone line or cut off the line at the telephone office from the terminal, the user’s telephone line will be dropped off and then played back and then connected, in which case the in-line telephone alarm will not be able to do so . The author designed and tested a successful phone break burglar alarm circuit. This alarm can be issued in the case of broken burglary sound short-term alarm (such as voice alarm caught thief, or other types), long time light alarm, and can record the start of the theft time