Its been reported in the press that some 60 2004 year model cars have
> tricked up radios that integrate the airconditioning system into a
> dealer-only supplied unit that cannot be pulled out and replaced with an
> aftermarket sound system. Some of these radios are also linked to the
> car's alarm and computer diagnostic system also. Presumably, the radio
> digital display is a multi-function display. It can display 870 kc or 78*
> F, depending on the mode. Behind the display may not even be a radio
> receiver! The components for the radio itself may be installed remotely
> from the display and there may even be room or attaching brackets for an
> aftermarket unit. You are screwed, in plain english. (On the other hand,
> who needs anything other than EOM sound anyways?)
There are so many electronic systems in modern cars that you need a common interface. The radio is a lousy choice but it's the only one that's standard at the moment. Ideally you want a large display and a decent input device like that found on navigation systems. Unfortunately nav systems are expensive options at the moment so car companies can't use them for other functions. In 5 years or so when nav systems are standard I expect that you will find that all of the user interface functions will migrate to that device and away from the radio. I also expect that by then the nav system display will be in the right place which is the instrument cluster not the center dash.