circuit for igntion/radio interaction

Hi, First post here, so bear with me! I've also not studied electronics in years, so it may be that what I'm asking is trivial or really hard - I don't know! If it matters, the car radio is a JVC KD-R721 and the car is a 2006 Ford Focus. With the stock Focus radio, you could turn on the radio with or without the key in the ignition, but if you had the key in and the radio on and then took the key out, the radio turned off. With my new radio installed, I can only turn the radio on with the key in the ignition. I would like to set things up so that things work as with the stock radio. I assume that part of this will be to hook the "Permanent 12v" wire into the radio, instead of the "Ignition 12v" wire, but I also want it so that turning the ignition off will kill the radio. Does that make sense? Is this possible? Thanks for your help.

That would be an internal feature of the stock radio, something your JVC won't be able to do. You could possibly set something up using an external button to trigger a circuit that would latch the radio on for a preset amount of time or until the ignition is cycled.Kevin Pierson

All the Euro cars do this, Ford,VW Audi another daft German idea (along with transponder immobilisers etc. It's built into the radio and it can't be done so forget it. There's a post here on retained ACC which might help.