Grundig 200 car radio can decode in the next way:
First step: Switch off the radio and the ignition as well.
Second step: Push the AS button and keep it pushed, at the same time turn on the ignition.
After this you will hear a beep sound. Now you can release the AS button.
Now you can enter the code in the next way: The first number can be set with the button ''1'', the second number of your code can be set with button ''2'' and so on. By pushing the ''1'',''2'',3'',''4'' buttons the value indicated in the screen will be increased by one. So if the first number of your code is 5 then you have to push the button ''1'' 5 times.
I hope the above are clear.
zsolt Dancsó, January 2007