RDC loses connection. Timeout? How to lengthen?

Two computers, an XP desktop and a 2000 laptop. Both connect to a
remote server. The IP we have to use is admittedly slow at times and I
think those delays are what causes the desktop to loose connection,
randomly, anywhere from 1 minute to a half hour. The laptop right next
to it can do the same connection for hours with rare problems. I'm
betting there's some registry setting for some timeout that is the
difference. Anybody have a clue?

Thanks,
Tom