From what I have read; two or more Robot Brains can not be tethered together so that they can communicate with each other. Though there is a workaround - Simon Burfield has a post for a moving platform. He was able to interconnect two Robot Brains with a Touch LED and a Color Sensor.
Would it be possible to get a firmware upgrade to the Robot Brain to allow easier tethering; just by plugging in a Smart Cable from one brain into the other? I would not limit this to just two units. One possibility is to have one Robot Brain acting as master control, controlling 12 other units (which in turn are controlling robots or something).
I understand that the competition rules do not allow more than one Robot Brain, but from an educational point it would be a great option to have. For example; having a factory assembly line project with each group creating one section of the line. With one key requirement that each section has to be tethered together to allow for an emergence stop button. If one part of the line has an emergence; then the whole line should stop.
Interested in other’s opinion/suggestions on this idea? Maybe one day we’ll see networked Vex IQ projects.