Issue found with my card reader interface; can't get existing program to connect

 CAUSE FOUND FOR LACK OF ERROR STATUS SIGNAL

I used an inspection mirror to look between the shield and the Arduino. Problem found! A pin from the shield was bent out of place and not inserted into the header on the Arduino. It was for pins 35 and 37, which includes the failing ERROR signal. 

A quick bit of bending and the problem was gone. I now get proper status for the machine. 

FAILING TO CONNECT FROM BRIAN KNITTEL'S CARDREAD.EXE

The program shared by Brian Knittel as part of his interface solution to the Documation card readers uses a virtual serial port to speak to the interface. It has been failing to connect to my instances of the board designed by Brian, which was the impetus for me to shift over to the Arduino based design I developed that will provide a more solid base for reading all the punched cards I own.

Sadly, it fails to connect to the Arduino either (or doesn't like something coming back from the Arduino which it interprets as an indication that this is not a valid interface). It fails on my laptop and on my older Surface Pro that I had been using with the readers in past years. 

This could be a problem introduced by Windows maintenance, breaking something for this old code. It could be an issue with my Arduino link also. I chat with my new interface over various terminal programs and everything appears good as far as I can tell.

I will proceed on two fronts simultaneously to overcome this last hurdle. First, I will write a Python program to manage the card reading, bypassing the need for the older program entirely. Second, I will write a program to masquerade as the interface to see what the program attempts, what it sends and how it responds to the intended responses. I will also dig around a bit to see if there are reports of other virtual serial port based programs failing due to windows fixes.