Stripe Snoop Logo
Parallel Port Adapter (El Cheapo!)

This is a horrible hack that I happened to make work. Unlike the other design, this one does not use a buffer chip to protect your computer's parallel port or motherboard.
You could very well fry/destroy your computer doing this! Proceed at your own risk!
I used an Omron V3A-4K for this Mod. I assume this will work with any reader from the V3A family. (Remember, V3B readers are simply V3A readers with black cases). Included in instruction are hints about making this mod work with other readers. Please email me (acidus @t if you manage to make this mod work with other readers.

Want to have the parallel port based reader with out soldering a cumbersome design or carrying around a battery all the time? This parallel port adapter requires no external power source, no chips, really nothing at all. This will be used to allow a game port based reader to be used with a parallel port.

All we are going to do are connect to proper lines from the game port to the parallel port, with a bit of a trick! Here are the materials you will need:
  • DB-15 Female connector. Make sure not to get he DB-15HD, which is a VGA plug
  • DB-25 Male connector
  • Wires
  • Hot Glue
  • Electrical Tape
Begin by soldering the necessary wires to the DB-15 and DB-25 connectors as shown in Table 1. It helps to use a permanent marker and write the pin numbers on the DB connector as shown. If you are trying this mod with another reader, solder wires to both DB connectors, and use a breadboard as shown earlier to make the connections.
DB-15 F Pin
DB-25 M Pin
25, 15
Data (2^8)
Data (2^7)
Data (2^6)
Data (2^5)
Table 1. Wiring between the DB-15 and DB-25 connectors
A close look at Table 1 should leave you scratching your head. There is no pin for 5V! We aren't powering our reader!

If you leave the 5V pin (normally pin 15 on the DB-15 Connector) loose, but do connect the GND, the difference between the GND and the hanging voltage pin is 5V as the picture shows. Its as if the GND is 5V lower the the surround air, so the reader is in fact being powered!
If you are using an Omron V3A/V3B reader, you can skip this step Only people trying to make this modification work with different readers and who are technically able should attempt this.

If you are trying to use this mod with another magstripe reader, you might need to mess around with the wiring. You should have used a breadboard to make the actual connections between the DB-25 and DB-15 connectors, and a common voltage meter will help. Perhaps your reader does need to be powered. The parallel port can supply 5V, it just cannot be used to drive or sink too much current. If you cannot drive your reader without connecting a rail, try soldering a wire to pin 2 of the DB-25 connector. In the CVS version of Stripe Snoop, there is a command called "ports." Ports will read the number of times a pin changes values, and is very useful in finding working readers. You can give it the "--power" command line option, and will turn pin 2 on the DB-25 connector "high," supplying you with 5V that might be able to drive your reader If your device draws or sinks to much current, this could damage your computer
After you are done soldering the wires to the DB connectors. use a hot glue gun to secure them. This prevents the wires from touching and shorting out, and it prevents the wires from being pulled out when you are plugging/unplugging the adapter

Note: Photo is from reader construction, so ignore wire placement. This is here just for demonstration purposes
If you did use a breadboard, go ahead and solder the wires from the 2 DB connectors together using Table 1. Use some electrical tape to secure and protect these solder points!

You are done! Simply plug one end into the parallel port and your game port reader into the other. Be sure to use the -P [port] option with Stripe Snoop version 1.6 to access the parallel port. Use: ss -P 0x379 for the 1st parallel port.

Last Updated: