After signing up for AllStarLink and installing the image, I was very surprised to learn that there is no option for using an ALSA soundcard in ASL. I already have no fewer than 20 USB interfaces, none of which work with ASL.
After some searching, I found a bit of information on a project to implement ALSA that is nearly a decade old and seems to have gone nowhere. Why is the system bound to a 20-year-old chip?
I will probably attempt to implement ALSA myself (I am generally familiar with Asterisk), but I will first have to build on OS using (by software standards) an ancient kernel before I can even compile the ASL source.
Since ASL works fine with a $4 sound fob ( https://www.ebay.com/itm/272374780193 ), I don’t suppose there is a lot of push to do anything more sophisticated.
As an experiment, I compiled ASL on Centos 7 the other day (w/ minor changes) and it seemed to go well. I have not finished that project though…
ALSA just gives more options. Virtually any USB (or otherwise) audio card you might come across will work with it. Several of the radios I own have USB audio connections direct–no fob even necessary. It seems ridiculous to do a bunch of soldering and cable-making when a simple USB cable could do the job just fine.
I wonder if ALSA (or some other supported Linux audio driver) support would be any easier in ASL3? Supposedly an RPi Zero 2 meets the ASL3 minimum system requirements, which would mean that one of those ($16) and an RPI Codec Zero hat ($20) would be about all that was needed (other than a radio, or mic and speaker for a radio-less node), with no need to modify/solder CM108 fobs/kits or pay $45+ for a CM1xx URI.
chan_alsa is still available in asterisk 20. It was deprecated in Asterisk 19 and removed in Asterisk 21. If you can compile from source, it is still an option under the channel drivers.
I have never used this driver. It may need some tweaks to work with app_rpt.