From reading the info on eham, it looks like this 1275 is basically a fancy PC interface like a Rigblaster, or something you could even make yourself if you did not want all the bells and whistles. In that case, any program for the sound card modes will work! My favorite is MixW, for lots of good reasons. If you want to start simple but clean, get a freeware copy of Digipan and try out PSK31. Then graduate to the $50 MixW that will give you all the other modes and every thing else you will ever need!
Look here: http://home.teleport.com/~nb6z/start.htm