The launch of OBD - in the US well before Europe - led to standardized access of vehicle networks.
In the US, the J1850 bus, standardized by the SAE, was used for this purpose.
After the bus was used for many years in its designs for Ford and GM, it has now been widely replaced by the CAN bus.
Softing has used the J1850 in large numbers for many years in its OEM-specific diagnostic interfaces.
OEM-specific diagnostic interfaces for use in independent and brand-specific repair shops.
For more information on the standard, please refer to the following sites
Wikipedia: SAE standards documents on OBD-II (EN)