Trailer connectors in Europe

A number of standards prevail in Europe for trailer connectors, the electrical connectors between vehicles and the trailers they tow that provide a means of control for the trailers. == 7 and 13-pin connectors == The 13-pin (ISO 11446) version being phased in is newer, provides more services than the 7-pin (ISO 1724), a more positive locking and also better protection against moisture and contamination.

Source: Wikipedia — Trailer connectors in Europe (CC BY-SA 4.0)