5 Steps to Remotely Control DO via MQTT丨Ursalink


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What is MQTT?

MQTT, also called Message Queuing Telemetry Transport, is an internet protocol designed for constrained devices with low-bandwidth. It allows users to send commands to remotely control DO via MQTT, read and publish data from sensor nodes and much more. It is commonly seen in the IoT (the Internet of Things) applications, where admins can easily establish a communication between multiple devices and realize centralized management.


This guide tells you how to remote control DO via MQTT in just a few minutes.

Gateway Configuration

Note: Gateway firmware version should be above You can downlaod the latest firmware here.

  • Step 1: navigate to “LoRaWAN/Network Server/Applications/”, click the Edit button.


  • Step 2: configure MQTT Parameters



  • Step 3: configuring MQTT.fx


  • Step 4: subscribe Uplink Topic


  • Step 5: control the DO

Publish Topic Format :


Sample :




  • For UC1122 & UC1152

Set DO1 high

{“confirmed”: true,”fport”: 85,”data”: “CQEA/w==”}

Set DO1 low

{“confirmed”: true,”fport”: 85,”data”: “CQAA/w==”}


  • For UC1114

Set DO1 high

{“confirmed”: true,”fport”: 85,”data”: “CQEA/w==”}

Set DO1 low

{“confirmed”: true,”fport”: 85,”data”: “CQAA/w==”}

Set DO2 high

{“confirmed”: true,”fport”: 85,”data”: “CgEA/w==”}

Set DO2 low

{“confirmed”: true,”fport”: 85,”data”: “CgAA/w==”}



IoT Glossary

MQTT (MQ Telemetry Transport) is an open OASIS and ISO standard (ISO/IEC PRF 20922) lightweight, a publish-subscribe network protocol that transports messages between devices. The protocol usually runs over TCP/IP; however, any network protocol that provides ordered, lossless, bi-directional connections can support MQTT. It is designed for connections with remote locations where a “small code footprint” is required or the network bandwidth is limited. The MQTT protocol defines two types of network entities: a message broker and a number of clients. An MQTT broker is a server that receives all messages from the clients and then routes the messages to the appropriate destination clients.[11] An MQTT client is any device (from a microcontroller up to a full-fledged server) that runs an MQTT library and connects to an MQTT broker over a network. (from Wikipedia)