I have an old Pactor II
modem (upgraded to Pactor III). Key consideration is my old Pactor II has an
RS232 (DB9)
serial port vs. the newer Pactor III uses USB. The connection from computer to modem is much easier with Pactor III USB modem. My Pactor II, needs two
serial cables from the computer, one for the modem and the other for
radio remote control. With the Pactor III, there's one USB cable from
laptop to modem, and two
cables from modem to radio. Most
computers don't have serial
ports, so you need two (2) USB to serial adapters or a dual adapter
(Gear-Mo has good one). Functionally, I didn't see any difference between my Pactor II modem and my friend's Pactor III USB. Also, the newer modems are a bit smaller.
Don