After reading some related posts and docs regarding the the infamous udev situation, I still cannot get a fully functional ttyUSB1 device file working for my Tungsten. Here's what I've tried which hasn't worked:
1. Upgraded to kernel 2.6.9-1.681_FC3.
2. I added this line to /etc/udev/udev.rules and ran udevstart, and also tried rebooting:
KERNEL="ttyUSB1", NAME="visor"
3. I tried copying the ttyUSB* files from another system to /dev and also /etc/udev/devices.
4. I manually created ttyUSB1 using: mknod /dev/ttyUSB1 c 188 0
After number 4, I was at least able to establish a connection with the PDA, however, during 8 attempts, the connection was lost each time. Any other suggestions would be greatly appreciated.