Seeking info for Cardamation parallel-serial board for card reader

[Ethan Dicks]

I have finally begun working with the card reader I picked up at a VCF
some years back.  Mechanically, it's sound, and the rollers are
adequate for short term use (on the top, one is firm and in good
shape, the other is starting the slide to goo but is working well
enough for short-term testing).  Mine came with a Cardamation-badged
microprocessor board inside that's a serial converter and so far, I'm
not getting any bits out of it.

I am fairly certain that the product I have was sold as a Cardamation
CF-600 based on pictures and speed.  I found this on the Wayback
Machine:

https://web.archive.org/web/20111003183529/http://www.cardamation.com/cardreaders.html

The board in question has a 6802 processor, two 6821 PIA chips for the
parallel interface, an EPROM, 1K of 2114 SRAM, an 8250 UART, and some
misc parts for an RS-232 level shifter.  Looking at the DB25F, there
are no bits coming out of pin 2 or pin 3.  I have yet to sit down and
trace signals all the way back, but it may come to that.

To assist my probings, while I can reverse-engineer the schematic,
locating any docs would speed up this process greatly.  On the board,
there are markings that indicate it's a "Cardamation Feature 92  Rev 4
 Assy No 023.0096-9".  The EPROM has a paper label indicating that
it's programmed with "V793NE76" whatever that means (likely the
variations are largely centered around what EBCDIC-to-ASCII mapping
was required).

I will be dumping the EPROM to ensure it has sensible contents.
Additionally, I'm always suspicious of 2114 SRAMs.  They fail while
sitting on the shelf.  Fortunately everything is socketed, so even if
it's an EIA line driver or a PIA or UART or even the CPU, replacement
is trivial.  There are no unobtanium parts on this outside of the
programming of the EPROM.  Absolutely worse case, I remove this serial
interface and build my own with a modern MCU (I believe Kyle Owen has
recently done this).

If this was 10 years ago, I'd probably start with Cardamation to ask
if they still had any docs on this stuff.  I'm reading they closed up
shop in 2011 so that's not an option.

Digging around for old Cardamation articles in trade rags, I see one
of their 300 card-per-minute units spewing the data at 19.2Kbps (I did
try that speed, along with 38.4Kbps).  I think the minimum speed is
going to be 9600 bps, but as I'm not seeing any bits on an
oscilliscope, I'm sure it's not the settings on the receive side
(yet).

-ethan