Wire an External Device to the Relays on the LRA-DCRX
The LRA-DCRX receiver features a relay to integrate and activate external devices like strobe lights or 12V DC outputs. The relay works only with Zone 4 and requires a separate power supply.
Published November 19, 2021
The LRA-DCRX receiver features a relay that may be used to integrate and activate an external device. For example, a strobe light, 12V DC output, or other devices may be configured to trigger when the relay on the receiver activates.
Tips & Notes
- The unit WILL NOT supply power to the external device. The external device must have a separate power supply.
- The relay ONLY works with Zone 4 on the receiver. For the relay to work, there must be a transmitter paired with Zone 4.
- The relay DOES NOT provide power.
- The relay may be set to normally open or normally closed.
- Ensure the relay is set to the "on" position.
- Set the duration of output to 2 seconds or 5 seconds.
In this example, we will wire a 12V DC siren to sound when the push button paired to Zone 4 is triggered.


What you will need
- A LRA transmitter (push button, door contact, etc.) paired to zone 4 of the LRA-DCRX receiver.
- 12V DC siren
- Extra wire (as needed)
- External power device used to power the 12V DC siren. In this example, we are using a 16.5 VAC /40VA Class II plug-in transformer. Please make sure the power supply you use will supply the necessary power to the external device.
- Ensure the power supply is unplugged.
- Wire one wire of the siren into one of the "normally open" connectors on the back of the receiver.
- Wire the other wire of the siren to the plug-in transformer.
- Take a wire and connect one end to the other slot of the "normally open" relay.
- Take the other end of that same wire and connect it to the transformer.
- Plug in the transformer. Ensure the receiver is powered on — test.

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