Documentation > nControl > Getting Started
This article explains how to connect a WiFi train controller to nControl.
How does the train controller communicate with nControl?
The train controller and nControl communicate through an MQTT broker. An MQTT broker is a 'message server' that can receive messages from one device and forward them another devices.
The broker creates a network of interconnected devices.
So the train controller needs to make two connections:
Configuring the Controller
The first time you use a controller you need to configure it so it can connect to the WiFi network and MQTT broker.
Verifying the Settings
Keep the controller connected to the micro-B USB cable and verify the settings by clicking on the Verify button. Your controller will first attempt to connect to your WiFi network.
![]() Once the controller is connected to the WiFi network, it will try to connect to the MQTT broker. ![]() Disconnect the controller from the USB cable. It's now ready to be used. Using the Controller
Connect the controller to the LEGO® battery box and switch the power on. The controller will automatically connect to the WiFi network and MQTT broker. It takes around 5 seconds for the controller to boot and to connect to the MQTT broker.
![]() You only need to configure the controller once. As long as you're using it on the same WiFi network, you don't need to reconfigure it; just switch it on and it will automatically connect. Troubleshooting
If the controller is not connecting to nControl:
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