This SAE Recommended Practice establishes the recommended locations for the air brake and electrical connections for towing multiple trailers. It applies to all commercial trailers except drop frame and car haul types.
SAE J849-2008 history
2013SAE J849-2013 Connection and Accessory Locations for Towing Multiple Trailers Truck and Bus
2008SAE J849-2008 Connection and Accessory Locations for Towing Multiple Trailers Truck and Bus
2003SAE J849-2003 Connection and Accessory Locations for Towing Multiple Trailers
1985SAE J849-1985 Connection and Accessory Locations for Towing Multiple Trailers@ Recommended Practice
1970SAE J849B-1970 CONNECTION AND ACCESSORY LOCATIONS FOR TOWING DOUBLES TRAILERS AND MULTI-AXLE TRAILERS