William was trying to show me how the entry unit works and the Hamilton handheld would not work. (The handheld, from what I have gathered, programs prices and the credit card computer.) William called Hamilton to try and get the handheld to work but nothing would work. Ends up that the cord was messed up (last picture).
I took the $1900 Hamilton credit card computer home with me to fix the handheld cord, which I did. I did not take the 2 boards apart but the top board looks like an Aprotek modem.