Since it has been ten years since I have made any, what brand USB Sound phobs is everyone using these days. I know I can purchase a pre made interface but I can easily modify the usb devices.
Have a look at this line. RA Series Radio Adapter Index Page
I’ve tested the RA42M. I like it.
The RA-25 works excellently as well as long as you don’t need any of the trim pots to make up for the radio hardware attached. I’ve used RA-25s with both SA818 chips as well as full-blown Kenwood repeaters with no problems.
Sorry I wasn’t clear. I meant what CM 108 USB phob are people ordering all Amazon.
I.'ve been using this one a syba, you need to crack the case to get inside though
https://www.amazon.com/Syba-external-Adapter-Windows-C-Media/dp/B001MSS6CS/ref=sr_1_2?sr=8-2
Hot air to remove the jacks - microscope @ #30 wire / E6000 Glue once the #30s are tacked - the rest is a 2N2222/5.6K for PTT and a couple of swamping resistors to taste on the audio levels…
I let the DSP on ASL take care of COR / PL Decode,etc - but you can add a 2nd Tranistor for COR/CTCSS Det if you want the extra trouble (and a 2nd #30 to pin 48 for COR IN)… de nu5d
BTW - a neat testing tool - I use UZ7HO’s Sound Modem 114 to get a waterfall view and PTT (with mark and space packet tones - but OK for quick go / no go test) UZ7HO Personal page - Packet-Radio - English version