986 Speedometer Signal for the Radio

[Highlow]

Originally Posted by vipola

On the Becker CDR-220 Radio, the Pin1 of the Plug A receive a signal from the Instrument Cluster to say the Radio what speed the car goes so it can adapt the volume..

Does anyone know what kind of signal is received by the Radio? is it a voltage? is it a resistance?.. and between what values is it travelling?

Thanks

I wish my headunit did this. I would pay for a unit that knows when the top is up or down, when the windows are up or down and my speed and took this all into consideration for the volume.