problem pairing controller and brain with radio

We are having a problem pairing our controller and brain via radio. They connect and function via the cable but when we disconnect no radio icon shows up in the window. Could this be a result of the brain not being fully charged? It appeared to have enough power to function and we tried the connection several times. Thank You mk

Hi marten,

We’re sorry that you have encountered this issue. The most common cause for when a Robot Brain and Controller communicate when tethered but do not connect over wireless are the physical connection to the radios.

To correct this issue, please check the radio in your Robot Brain and Controller, and first ensure both of these radios are the same type - either the grey 900 MHz Radio (North, Central and South America only), the black 2.4 GHz Radio (worldwide) or the blue Smart Radio (worldwide). Each of these three types of radio can only communicate with other radios of the same time. For example, a Robot Brain and Controller cannot communicate if one is using the Smart Radio and the other is using the 2.4 GHz Radio.

Next, please check the radio connection in both the Robot Brain and Controller. When the radio is fully inserted, only about 7-8mm (slightly over a quarter inch) should be visible. To fully insert the radio into the Controller, please remove the battery door then insert the radio. To fully insert the radio into the Robot Brain, please press and hold down the red button on the bottom of the Robot Brain while inserting the radio.

Finally, if you are using the Smart Radio, you must use Robot Brain firmware v1.16 or newer to enable this functionality - the Smart Radio will not work on older firmware versions. To upgrade the firmware on your Robot Brain, please install the VEX IQ Firmware Update Utility to your Mac OS X or Windows computer. Once installed, please connect your Controller to your Robot brain using the Tether Cable, then connect your Robot Brain to your computer using the USB Cable. Then turn on the Robot Brain, and open the VEX IQ Firmware Update Utility on your computer. To update your Robot Brain firmware, please select the “Smart Radio” button in the program window, then click the “Update all Components” button. Screenshots of this process are available in the Smart Radio User Guide.

If you have any additional questions or if the tips above do not resolve your issue, please contact VEX Technical Support at or by calling +1-903-453-0802 so we can provide additional assistance and make this right.


  • Art
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