The RJ31X Jack is a special, 8-pin telephone jack, designed for use with security systems and which is available from your telephone company or from your Alarm Installer.

Your system is designed to plug into this RJ31X Jack, which is installed at your premises on one of your regular telephone lines and is located near your security panel.  When activated, a relay in your security system panel "seizes" the telephone line and gives the security system priority use of this line.  This allows the security system to report its emergency signals to the Central Monitoring Station's alarm Receiving Equipment without being blocked by normal telephone usage at the premises.

In the event of a malfunction of your security system, the RJ31X Jack will provide a mechanism for quickly unplugging, and thereby disconnecting, your security system from the telephone line.   This will allow you to use the telephone without the interruption of transmitted alarm signals.