PR49-24L initial connection to PR55-21 MQTT

I am trying to get a PR49-24L to send it’s first messages to a PR55-21 MQTT.

Current Setup

  • I have an existing mosquito broker that is running and serving messages from existing esp32 based sensor boards.
  • I have set up the PR55-21 MQTT gateway to connect to this broker and I see the connection and registration of the topic when the gateway starts up in the brokers logs.
  • The PR55-21 MQTT gateway currently has a red flashing light and seems to be ok.
  • Opened the top of the PR49-24L to power it on and found the power switch already in the ON position. Checked the voltage on the batteries and found ~1.6v so it had not been on for too long. Flipped the switch back and forth while holding the CFG button to confirm the position for ON. The status light only comes on when the switch is in the on position, that was confirmation enough for me.

Issues / Troubleshooting

  • I am trying to troubleshoot why I do not see any indication of a connection from the sensor to the gateway.
  • Currently I do not see any logs of messages coming in on the new topic created by the gateway.
  • The PR49-24L STAT light only comes on when holding the CFG button. Nothing happens when pressing the RST button.
  • When putting the gateway in config mode, I do not see the sensor in the Devices tab but I am not sure if it should.
  • I have tried many iterations of power cycles and holding config buttons for 15 seconds but I do not notice any change in the sensor or any indication of a connection between the sensor and gateway.


  • I did not see an explanation of the status lights in the documentation. Is this information somewhere?
  • What options do I have for troubleshooting the connection of the sensor to the gateway? From the documentation it seems to be expected to just work.


When the MQTT gateway has a valid connection to the WiFi network and the MQTT Broker the LED should be green, not red. Red indicates an error.

Can you provide top down photos of the MQTT Gateway and the Sensor with the top lid removed?

Thank you,
Travis Elliott

Sure thing. Attached are the two photos.

The photo of the gateway was caught with the LED on but it is flashing on a ~1 sec interval.

Hi David,

1 flash per second actually indicates that the S3B module inside the Gateway is not reachable.
I would recommend sending the devices in for RMA so we can repair that for you. There is nothing you can do to resolve this on your end. Not sure how that could have happened. Everything is tested prior to shipping.

You can fill out an RMA form here:
upon completing the form you will receive an email with an RMA ID number along with instructions on returning the devices.

Thank you,
Travis Elliott