My wireless alarm system was "deaf" and "dead" during the use of an FCC like authorized low range and power wireless radio "headphone", that simple...
Unfortunately this authority authorized and certified device transmitted on the shared and not protected wireless alarm system frequency, a lot of "other" low power transmitters have the same bad effect. : It muzzle any possible incoming signals from the sensors.
This problem is well known in telecommunication and is called "Radio Frequency Interference" (RFI). This wireless headphone story shows me how EASY and SIMPLE it is to have the operations of any wireless alarm system jeopardized completely from the outside. There are identifications codes present in the sensor transmissions but during RFI the receiver output goes bingo and the ID's are undecodable, the system is just useless. The system does no longer detected FIRE and/or INTRUSION; the receiver is "deaf" and "dead" on alarm giving.
This is applicable to OLD and NEW equipments, the receiver is unable to refuse the RFI signals only and keep the sensor data, he jam everything even the RFI detection and alarm giving.
Think it over before you keep or get a wireless alarm system. I know, this problem happens only to others but you..