Hi George,

I designed and builded RF card readers using AT89C2051 controller.
The readers uses 125KHz read only tags ( H4002).
They are stand-alone devices with 408 cards data base.
No external switches (or keyboard) neded for data base management.
A RS232/V24 serial interface is provided witch extend the functionalities of the reader.
I am going to design a portable reader witch will be ready soon.
If you want I can mail you a documentation and some pictures of the reader.

Best regards,

Cristian