Signal support systems. They learn about computers, radios & etc. to keep troops able to communicate & etc.
When your son arrives at Ft Gordon he will be in processing for a few days, then he will go to FOB (they train with what they call Iraq conditions), when he is at FOB he will have no way of contacting you. he will be at FOB for about a week then he will be assigned to his barracks.
He will get into classes as soon as room is available. Let your son know to pay more attention to the teachers, study his work and for tests. If he fails a test he will be "recycled" which means he will have to start class over from where he failed and it could take weeks or month to get back into. He will do TAK duties which include cleaning, mowing lawns, painting, moving furniture & whatever else needs to be done, while he is not attending classes. Also advise your son to stay on track & go to all formations, he will be "phased up" quicker which will give him more freedom.