the Sony Stalk commands won't be pretending to be RDS packets as the RDS processing is done within the DSP [Altman (Hugo) told me this about 6 months ago when I asked about the Sony Stalk Interface and RDS Tuner interface and Tuner interface pinouts].

He also indicated that the 'serial' interface between the tuner and player is used for send tuning commands to the tuner module and to get Sony Stalk 'buttons' as well as signal strength information and tuning info.

The Stalk buttons are managed in the Tuner by a PIC Micro and the ADC values read are output to the unit via the serial interface.

So the likely device to read is /dev/tuner as thats where the data will be turning up.

How difficult would it be to 'monitor' the traffic between the player and /dev/tuner? [I imagine a simple trace facility intially - possibly in the kernel that dumps all tuner interface traffic in human readable form to the serial port and from that we can work out whats going on].