J1587/J1708 dongle/hardware interface for RV?

Any of you owners of older RVs/Motorhomes/School Buses, Trucks, Bulldozers(?) have insight into dongles or hardware devices to read J1587/J1708 signals? My RV has a 6-pin Deutsch connector rather than OBD2, and J1708/1587 is apparently an RS-485 (NOT CAN)- based protocol. For cars, there are tons of cheap OBD2 CAN dongles as well as lots of reader/interpreter software, but I haven’t found anything cheap or free for J1587/1708.

I’m looking for both hardware (dongle/interface) and reader software to see if I can get any data out at all before I tackle integrating with RealDash. Anyone have any finds?

For anyone else looking to connect to heavy equipment, let me share what I’ve learned so far: “Heavy equipment” means anything, well, heavy, including larger RVs, Trucks, Buses, Tractors, Construction Equipment, even Yachts apparently. There are two (that I know of) standards: J1708/J1587 and J1939. J1939 is the newer (introduced 2001), CAN-based standard, and it (1939) should be as simple to integrate as any other new vehicle manufacturer.
J1708/1587 is the older predecessor to J1939, and as such it is NOT CAN-based, hence my question. The good news for both standards, however is that all the data in them is standardized - i.e. heavy equipment manufacturers learned from the fragmentation of data amongst car manufacturers (thay all implemented their own proprietary standards), and agreed to all use the same signals/messages/frames (still learning that part), so that once you can get RPM or Vehicle Speed or whatever for, say, Freightliner, you also have it for every other brand - Caterpillar, Peterbilt, Mack, Kenworth etc etc