Rob thanks for replying,
Unfortunately, as stated earlier, my Onkyo model TX-DS939 does not have an rs232 port.

What I aim to achieve is exactly to convert these IR codes to 2-way communication in one way or the other.
I can control the receiver by sticking an IR blaster LED onto the receiver - LinuxMCE will thus be able to convey (PRONTO) commands to the receiver via IR-blaster. This is of course only ONE WAY communication.

I would like to set up 2-way communication (hopefully) by means of using these RI (remote interactive) jacks.

I'm looking for help on how to get started intercepting / translating the signals on this bus.

As far as I have read here and there it seems that the same rs232 communication language is also used on USB bus and (???) on this Remote Interactive bus.... Not sure about this though...

Thanks for your information,

Erwin