I am a ham radio op -- running a program called fldigi. Works fine under XP, which I hate to use.
However, under Ubuntu 10.04, running ALSA and Pulse Audio, I cannot get sound from the sound card coming in from the radio to go to the program. It comes through the headphones well. I also cannot get any audio output from the program to the radio.
I have been around the block trying this, that and t'other thing -- messing with sound card configuration, etc., to no avail.