Overview
The Simon XT is a wireless all-in-one alarm panel originally sold under the GE Security brand and later Interlogix. It was one of the most common dealer-installed panels of its era: the keypad, siren, voice prompts, and wireless receiver are all in one wall unit, and sensors are Interlogix/GE 319.5 MHz learn-mode devices.
Interlogix stopped making intrusion products around 2020, so the Simon XT and its touchscreen sibling, the Simon XTi, are no longer manufactured. Existing systems keep working, but new parts and communicators are getting scarce.
At a glance
| Type | All-in-one wireless panel with built-in keypad and voice |
|---|---|
| Sensors | Interlogix / GE 319.5 MHz learn-mode wireless |
| Communication | Phone dialer; plug-in cellular module (older 3G modules no longer work) |
| Default codes | Installer 4321, master 1234 |
Error Codes
The Simon XT announces troubles with voice prompts and its display, and reports them as "system trouble" until acknowledged. The usual causes are the same as on any panel: a sensor with a low battery or no signal, AC power loss, a weak panel battery, or a failed connection to the monitoring company. See why your alarm is beeping and sensor low battery.
Troubleshooting
It stopped communicating
Many Simon XT panels used 3G cellular modules, which stopped working when US carriers retired 3G in 2022. If your panel can no longer reach the monitoring company, you have two options: an LTE communicator compatible with the Simon XT, if your dealer still supplies one, or replacing the panel. See communication failure.
Keeping your sensors when you replace it
Because the sensors are 319.5 MHz Interlogix/GE devices, some newer panels can learn many of them, which can save the cost of new door and window sensors. Qolsys panels with 319.5 MHz support are a common route. Ask the installer to confirm which of your specific sensors will transfer.
Low battery that keeps coming back
Both the panel's backup battery and individual sensor batteries age. Replace the panel battery with the correct pack for the Simon XT, and check the sensor listed in the trouble.
Compatible Peripherals
Interlogix/GE 319.5 MHz learn-mode sensors, keyfobs, and remote keypads made for the Simon family. When replacing the panel, see the Qolsys range for panels that can learn compatible 319.5 MHz sensors.
Installation Notes
- Programming uses the installer code (default
4321). See installer and master codes. - Sensors are learned into the panel in programming; each needs its zone type and name set.
- Put the account on test before removing the panel from its back plate or testing sensors.
FAQs
Is the Simon XT still supported?
It is discontinued, so no new units are made. Many dealers still service existing systems, but plan for replacement if your communicator fails or parts become hard to find.
What is the difference between the Simon XT and Simon XTi?
The XTi has a touchscreen and newer features; both use the same family of 319.5 MHz sensors.