A duress Passcode is used to send a silent alarm signal to the Central Station simply by increasing the last digit of the Passcode by one. For example, if the standard Passcode is 12345, the duress Passcode is 12346. The duress Passcode arms or disarms the security system just like your personal Passcode; however, as the system is armed or disarmed an alarm signal is transmitted to the Central Station.
The duress Passcode is used when someone threatens you and demands you to disarm your security system. By disarming (or arming) with a duress Passcode, the Central Station is alerted of an alarm situation.