Friday, May 4, 2018

Building card reader interfaces for Documation readers

DOCUMATION CARD READER INTERFACE

I took some time to design and send away for a printed circuit board to build the interface that hooks a Documation card reader to a PC through a USB cable, based on the design by Brian Knittel but with a different USB/Parallel port module since the original he specified is unavailable.

This has a SX28AC controller on the board, making use of a 82C55 IO port device and some support components. This will be placed on the rear of the card reader, replacing the bulky and expensive signal connector from Documation.

My board is 4" square and has connectors to plug in the USB module, connect 5V power, connect to an End of File pushbutton and indicator LED, plus a dual header to connect to the 17 signal wires from the Documation.

Simple PCB for card reader interface
I have all the parts as well as the boards on order, with components for two boards and three PCBs (since that was the minimum order) coming. When it is all here, I will put together two boards and wire these into my two Documation readers. 

My original reader runs at 600 cards per minute while the other is faster, at 1000 CPM. These are very handy when someone shows up with several boxes of data or programs on punched cards.


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