带密码锁控制的电话接线盒朱建坤本文介绍一种新颖、实用的带密码锁控制的电话接线盘电路。功能及特点１．有效控制无权用户拨打外线电话。采用密码锁电路代替传统的机械锁控制外线，具有保密、安全及控制可靠特特点。当外线有电话打人时，本盒能自动识别并开锁，不影响电... Telephone Junction Box with Code Lock Control Zhu Jiankun This article presents a novel and practical telephone patch circuit with a combination of code lock control. Function and Features 1. Effective control of no outside users to make external calls. The use of the password lock circuit instead of the traditional mechanical lock control outside, with confidentiality, security and control of special features. When the outside has hit the phone, the box can automatically identify and unlock, does not affect the electricity ...