MOD-RFID125 custom encoding

[itec]

Hi.
I have several MOD-RFID125.
Now I'd like to customize the output, changing the encoding and the string terminator (TAB instead of CR)
Is it possible to have the sources, so I can modify them and flash a new firmware?

We've an access control system that uses a proprietary encoding of tags, it would be nice to have a reader that can output exactly the same code.

BR
Emanuele