Ken:
Once you start using a soundcard and AFSK on RTTY contest you will never want to go back. I used to contest with AEA PK-900's and I can't imagine doing that ever again.
One of the key advantages to soundcard AFSK is you can leave the rigs bandpass open and use a mouse to interrogate signals of intrest by simply clicking a mouse. It also makes tuning to a RTTY packet spot 100 times easier.
I use a Microham MK2R+ for my SO2R control, and this unit also provides two isolated soundcards, Two Serial Ports for CAT control, Antenna Switching, Winkey, and much much more! I am aware Array solutions has thier own varient of SO2R controllers as well. You should probably take a look at both, as they seem to be the main source for SO2R control. Their used to be anotehr vendor that made controllers out of Europe, but I have not seen the advertise in sometime, and believe they have since folded.
73
Rich, AJ3G