I just thought I'd share that the 6th generation Accords (1998-2002) utilize the M-Bus (as I suspected). I've made my own adaptor with an AVR microcontroller using info from
here. So far it seems that all the control codes are the same. The only thing that is different is the connector. I'm working with JAE Connectors to get some samples. It seems that adaptors such as
this are really just connector adaptors at a hefty premium!
That adaptor's page has some interesting statements about all its advanced "circuitry".
Quote:
Peripheral's new "IL" interfaces revolutionize CD changer interface technology. One look at the internal circuitry reveals surface mount technology which utilizes a microprocessor for a truly state-of-the-art interface. The all digital interface ensures reliable operation and easy future software upgrades.