I was just up on eBay and there is a card for auction that I have never seen before.
The Item number is 280724325328 and it seems to be a mouse interface with a SCSI connector.
Any ideas? 
Anonymous
User login
Please support the defense of Ukraine.
Direct or via Unclutter App
Active forum topics
Recent content
Navigation
No Ads.
No Trackers.
No Social Media.
All Content Locally Hosted.
Built on Free Software.
We have complied with zero government requests for information.
Here is the URL:
http://cgi.ebay.com/APPLE-COMPUTER-II-IIE-IIC-EXTERNAL-MOUSE-PORT-ADAPTER-/280724325328?pt=LH_DefaultDomain_0&hash=item415c7943d0
The only thing I was able to find on it:
http://www.mail-archive.com/apple2list@mail.maclaunch.com/msg02751.html
"Apple SCSI Loop Back Test Card, 077-0219, Provided by Apple for techs to test SCSI ports, most likely on Macs, Apple IIe"
It seems unlikely to me that it was to test SCSI ports on IIe's, but perfectly reasonable that it was for Macs.
Thanks David!