Vex EDR Cortex not Communicating with PC
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Author:  Antlerman [ Fri Apr 01, 2016 5:53 pm ]
Post subject:  Vex EDR Cortex not Communicating with PC

Greetings All,

All of a sudden I'm having difficulty getting my Vex EDR Cortex (802.11g) to communicate with my computer. The Communications window indicates that the "COM 3" "Port is disconnected" and the Status is "Offline".

On the Cortex the Robot light is green and blinking slowly while the Game light is also green but blinking very quickly.

I've tried power cycling, changing my Communication Mode from "USB only" to "VexNet or USB" and still the problem persists. I have another robot and the cortex works fine under the same RobotC settings so I figure the problem has to be the cortex in question. Any idea what could be wrong and how and I can get the cortex running again? Any suggestions would be most appreciated.

Thank you!

Author:  CARBOT [ Fri Apr 01, 2016 7:33 pm ]
Post subject:  Re: Vex EDR Cortex not Communicating with PC

The original Vex Cortex used 802.11 wireless but the new WHITE wireless keys are a proprietary signal.

Neither one allows you to communicate directly between the PC and Cortex. You must communicate from the PC to the Joystick with the USB cable then the Joystick and Cortex can communicate wireless.

Here is a pdf and video of how to do it: ... 081811.pdf

Author:  Antlerman [ Mon Apr 04, 2016 11:21 am ]
Post subject:  Re: Vex EDR Cortex not Communicating with PC

Hello Carbot,

Thank you very much for your response. I followed your exact instructions several times and got the following results. The Cortex "ROBOT" LED continues to blink green slow and steady while the "GAME" LED blinks green once approximately every 6 seconds.

On the Joystick the "JOYSTICK" LED is at a constant red while the other lights blink red every 10 seconds or so. The Cortex and Joystick never manages to link up.

Please advise on my next steps toward establishing communication between the cortex and PC and joystick so that I can begin programming my robot.


Author:  CARBOT [ Mon Apr 04, 2016 8:58 pm ]
Post subject:  Re: Vex EDR Cortex not Communicating with PC

I always use the Cortex in a standalone autonomous mode. I followed the video and got the Cortex to work with my new WHITE Vexnet keys.

If you have a competition switch or simulation device please disconnect it.

If you are using the old Black Vexnet keys I recommend you swap one because they are prone to connection issues.

Make sure your joystick and Cortex batteries are in good shape.

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