I picked up the rfid scanner and a selection of tags from thinkgeek (i dont think they have them any more) and then I found out the scanner comes from Phidgets here in Calgary, I could have drove over and avoided a lot of hasle, even tho thinkgeek did nothing wrong and is a great place to shop generally.

I played with the phidget software some but was unsatisfied with the demo software so I wrote this software for my linux systems, see the README in there.

When I first ordered it I was unaware that there were so many different types of rfid standards and I thought this reader would be able to read tags from stores and security systems and whatever I want but it seems it will not work with anything except its own tags. These tags use the 125khz EM4102 protocol from "EM Microelectronic - Marin SA" (emmicroelectronic.com).

The EM4102 lazer etched rom contains 64 bits divided in five groups of information. 9 bits are used for the header set to logic 1, 10 row parity bits, 4 column parity bits, 8 version or costomer id bits, 32 data bits, and 1 stop bit set to logic 0.

So the actual useful data bits are just 40 bits of cust id and data. The spec also states the data cannot contain 9 consecutive 1 bits to prevent confusion with the headers bits so this further restricts the available data combinations.

Phidgets has discontinued this model in favor of a more flexible read/write interface now.

some of the Common RFID protocols:

    EM4100 Series
    ISO11784/ISO11785 (FDX-B)
    EPC class 0
    EPC class 1