Default How does the external keyboard work?

Hi there,

I would like to know if there's anyone outside who connected a self build keyboard to a XDA? How does the Keyboad communicate via RS232?

Does someone know something about building a converter: PS2 to RS232 ?
What kind of information does the XDA need to notice that there's a keyboard connected?

I could try to use a simple AVR-Processor programmed to convert the signals. Building the Hardware should not be the problem but understanding the data transfer protocoll is difficult.

Any datasheet out there?
Rom-Version: 4.01.19 GER
Rom-Data: 03/05/04
Radio-Version: 4.21
Protocol-Version: 32S54