I run Supra's and was having the same trouble. It was really odd only on a couple of 14.4 users. It would hang the port with the 300 and I would have to reboot. I updated my Modems to the latest beta version, I think it is 4425. You can download the software from the Diamond/Supra Beta site or off of my system in Telecom. Just use a term (Like Zterm) hit at** to put the modem in flashmode and receive the file xmodem.