OK I have managed to get some code that can detect the presence of a tuner... but it can't work out the ID as I am not getting the responses back I expect.

(I think) I am sending the bytes 0x01, 0x09 then when I read back 4 bytes I get 0x00, 0x02, 0x02, 0x37 (I think)

This only happens when I have the tuner connected so I can use this much to detect the presence of the tuner... but the response doesn't change at all if I change the tuner's ID...

I am about to go back and try sending the 3 byte init string Hugo originally sent me of 0x01, 0x00, 0x01 and see what I get back...

I am also pretty certain I am not dealing with the serial port registers correctly as when I plug it into the mains after having initially flashed a kernel the reading times out (as expected) but after taking it to the car and testing (and getting the 4 byte response) when I bring it back in and plug it into the mains it doesn't timeout and instead manages to "read" 4 bytes of 0x00...

Cheers

Kim