For the impatient
In order to record audio you need a special alsa state file and we provide a link to one that works below (SHA1:55888a699e969c5e2c4690e6aff47ccad7ad0f3d). It can be used to put the device into voice recording mode.
alsactl -f voip-handset.state restore arecord -D hw -f cd -v -t wav rec-$(date +%Y-%m-%d-%H-%M).wav
With these commands you should get a file in Waveform audio format (WAV) in the local directory.
Applications that record audio
In alphabetical order.
Information for developers
Mixer settings for voice recording: It is required that DAI Mode (alsa control number 50) is "DAI 2". As of 23/Feb/2009 "DAI 1" mode is broken. Not all the DAI modes work and people are working on this.
Here we have a list of relevant tickets that are open now: