Probably I'm not the right person to respond to you, and certainly not to say this: but your post lacks information.
I'm not really into hardware, so I don't really knwo much about this. I know, however, that I was not able to get USB running with Mandrake 8.2... so I'm not sure that RH 7.* could.
try this link:
http://www.redhat.com/docs/ and in the search field write 'USB 7.3' and read through.
What dev are you plugging in the USB?