This is a simple three track magnetic card reader with serial output. This reader takes power from the serial port and outputs a 9600bps 8N1 ASCII serial stream.
Plug the reader into a serial port (or USB to serial converter), swipe your frequent shopper card, and you'll see the account number plain and unencrypted on the screen. We couldn't find a card the reader couldn't read. No drivers needed. No software needed. Just pure, wonderful serial.