SAE J1939-13 specifies the diagnostic connectors used for off-board connection to a vehicle's SAE J1939 communication links. The defined diagnostic connectors support connection to the twisted shielded pair media (SAE J1939-11), the Reduced Physical Layer unshielded twisted pair (SAE J1939-15), the unshielded twisted pair of SAE J1939-14, as well as the twisted unshielded quad media (ISO 11783-2).