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本装置的特点是利用电话机的本身键盘,兼作输入密码键盘。在话机摘机后、未输入正确的密码前,键盘与话机原线路脱离,这时听筒里虽然能听到拨号音,但号码拨不出去,即电话处于“锁”住状态;当输入正确密码后,键盘与话机线路接通,即打开了“锁”、就可恢复向外拨号了。因此本装置同其他电话锁相比,突出了下列优点:①适用性强(无论发号方式是脉冲或是双音频的);②给使用带来方便;③线路通俗易懂,结构简单。
The device is characterized by the use of the phone’s own keyboard, double as the input password keyboard. Before the phone picks up the phone and does not input the correct password, the keyboard and the phone are disconnected from the original line. In this case, although the dial tone can be heard in the handset, the number can not be dialed, that is, the phone is in the “lock” state. When the correct password After the keyboard and the phone line connected, which opened the “lock”, you can resume dial out. Therefore, compared with other telephone locks, this device prominently has the following advantages: ①High applicability (no matter whether it is pulse or dual audio); ②It is convenient to use; ③The circuit is easy to understand and the structure is simple.