Near the battery on the right side.
...
Near the battery on the right side.
...
Near the battery on the right side.
Tuomas, you're not going to find a free round plug... you will find a rectangular ISO 10-position connector (similar to VW/Audi 8-position connector). To get to the round plug of the Alpine, you need the adapter from someone like PIE.On the left I found electic cables but none of them seemed to end up in a free round plug.