Aren't these pure audio (no MIDI syntesizer on board), multichannel cards? I guess you need a break-out-box to have any inputs/outputs.

I only found out they're from some kind of DAW. Not much info on them. When I first saw them thought they were SCSI controllers...
I wonder if this break-out box has any complex schematics.

Do you have any better photos? front & back of one card.
a symbios logic 53c710 would also make me think scsi controller. It can ofcourse be both.

More better photos.

yeah, that's definitely part scsi.

My guess is that it is a sample based sound editing solution. For like mixing in recording Studios.
After a little bit of googling i found an oldlisting on Aliexpress for this card. https://de.aliexpress.com/item/32895103941.html
It looks like it was a solution with several different cards and (as mentioned before) some breakout boxes. The boxes would contain the analog to digital converters, and the cards handle the digital stuff and sample management.
With the information from the aliexpress picture i looked up the second card and found this : http://www.oldschooldaw.com/forums/index.php?topic=681.0
Here you can get a small glimpse of what it could do.
Your card seems to be a disk controller for loading the samples from scsi.

BUT its all a guess on my side.

Good Luck.

Whoa, DerBaum, thanks a lot! Didn't know that much info on them existed at all. On the other hand, they seem to be mere interface cards (wouldn't guess with that many ASICs and all) and almost no hope they'd work standalone... But very educating nevertheless.