Towing hitch

Hello together, I could get a detachable AHK for my Omega. But without electrics. Now I looked for AHK in the forum and read everything about it. Nevertheless I have a few questions. Which cable equipment (7- 13-pin, Checkcontrol) should I take. What should I pay attention to. For manufacturers and other tips I would be very grateful. Greetings PS. Of course I also come to Nierstein to the meeting.