For those who haven't seen my post explaining what this device is all about, see here:
https://nfggames.com/forum2/index.php?topic=7618.0
That being said, I wanted to share that I recently got the ArdSCSino Plus working on my PC-9821 Ap2/U8W.
To do so, I needed to use a special, generic SCSI CD-ROM driver, which you can download here:
https://drive.google.com/drive/folders/1WVFHWGHf85AQ4byh6KqYBroDH-GCBsnA
Notes on this driver's usage can be found here:
https://blog.tlfoxhuman.net/2023/08/09/use-scsi-cd-drive-on-pc98/
It functions more-or-less the same as other CD-ROM drivers, but takes an /I argument to specify SCSI ID.
For example...
DEVICEHIGH=A:\CDDRV.SYS /D:CD_101 /I1
Anyway, I just figured I'd share! This device isn't incredibly easy to get a hold of, but if you manage to snag one, it works beautifully. I even routed the 3.5mm audio output from the ArdSCSino Plus into the "LINE IN" on the rear of the Ap2 for seamless passthrough.
Small update, unfortunately I cannot get the device coupled with that generic SCSI driver to work with Policenauts. There is strange audio and graphic glitching that I don't see when using an original file-slot CD-ROM drive.
Figured I'd share for those who may encounter this in the future.