For security reason, the alarm system manufacturer always has their own code for encoding and decoding the communication system.
So, one brand wireless alarm device can’t be compatible with another brand wireless alarm device directly.
Focus alarm system has many compatible wireless alarm accessories such as wireless smoke detector, CO detector, gas sensor, vibration sensor, door contact, PIR, curtain PIR, wireless keypad, panic button, wireless siren strobe etc.
People always buy and install the basic alarm system at first time and add more sensors and accessory later on.
Below we list some of the compatible focus wireless alarm accessories and wireless sensors in picture.