This document specifies the locations of coupling devices for electrical and pneumatic connections between towing and towed commercial road vehicles. It is applicable to heavy vehicles equipped with pneumatic braking systems and 24 V electrical equipment of the following types: drawbar-trailer combinations, centre-axle trailer combinations and multiple-vehicle combinations whose towing vehicles or trailers have rear‑mounted couplings or couplings mounted forward and below, and articulated vehicles.

This document is not applicable to car carriers, or road vehicles equipped only with fully automatic coupling system (FACS) according to the ISO 13044 series, not mounted on the front of the trailer.