5.2.1.23.

Power driven vehicles authorized to tow a trailer equipped with an anti-lock system shall also be equipped with either one or both of the following, for the electric control transmission:
(a)    A special electrical connector conforming to ISO 7638:2003;[7]
(b)    An automated connector meeting the requirements specified in Annex 22.

 a1c0
5.2.1.23. Power driven vehicles authorized to tow a trailer equipped with an anti-lock system shall also be equipped with a special electrical connector, conforming to ISO 7638:2003,[3] for the electric control transmission. a0c0