In particular, it shall not be possible for th
e adjustment of the lamps to be inadvertently disturbed. 3.1.1. Tractors mu
st be equipped with electrical connectors to enable a detachable light-signalling system to be used. In particular tractors must be fitted with the permanently connected socket outlet recommended in standard ISO R 1724 (Electrical connections for vehicles with 6 or 12 volt electrical systems applying more specifically to private motor cars and light-weight trailers or caravans) (first edition, April 1970) or ISO R 1
...[+++]185 (Electrical connections between towing and towed vehicles having 24 volt electrical systems used for international commercial transport purposes) (first edition, March 1970).
