J1939 Backbone (Triangular) Connector cable - found on several off highway vehicles.

Vehicles and Uses:

Engines: Cummins
MFG: Cummins, Twin Disc
Bus: Volkswagen
OHW: Komatsu, Hyundai CE, Hyster

This cable requires external power supply connected to the VCI.
The diagnostic port on the vehicle is typically located near the engine block.