$ arecord -vv -D headset -fcd test.wav $ aplay -vv -D v8237 test.wav
Hit CTRL +C stop either command.
A couple of random nuggets: run cat /proc/asound/version to get your ALSA version.
The examples are from the onboard sound on my low-budget ECS motherboard. As you can see, it supports digital output (S/PDIF = Sony-Phillips Digital Interface) in addition to analog. However, I can't use it--there is neither connector nor headers on the motherboard. Beware when you are buying sound cards, because they often claim "24-bit digital sound!" or some such. All computer sound cards support digital sound- their main job is converting digital sound files for analog speakers. If you want digital output to digital speakers, read the specs carefully to be sure you're getting real 100% digital.
This article was first published on LinuxPlanet.com.