It is also ISO11783. So any mechanic who can work on large diesels (semi trucks) will have the tools. Some of the $150 OBD-II readers at an auto parts store can do it (only some though - most do not have the adapters: it is a different connector and different data on the wires).
If you are reading this you can probable figure out how to wire up an arduino as well. The electronics are easy, though you probably have to buy the standard from ISO to write the code.
Note, the above covers current tractors. Some of the older tractors used an older protocol, God help you if that is your tractor.
It effectively claims that the guy couldn't repair his machines without a specialist who had to be flown out directly. I guess it's not a question of OBD-II, so my bad for making it about that, but it's still a question of repairability. I can't find a first hand account from him, so I'm willing to believe it was more complicated than a single paragraph in Wired. Why couldn't he just buy the manual and repair it? What codes and interfaces don't show up on OBD-II?
I work for an automaker, and I'm well aware that you can get the base codes from a cheapo harbor freight OBD reader, but that won't let you reset all of the errors you might be getting, and OBD codes don't tell you as much as the engine computer knows, for that you need $4000 worth of hardware and a yearly license for very expensive hardware. John Deere is no different, if the mechanics I've talked to are any guide.
I guess the point I'm making is that the availability of a manual is only so good if it says "hook up your Tricorder and check this hex address." I would need a Tricorder for that, and I'm fresh out.
If you are reading this you can probable figure out how to wire up an arduino as well. The electronics are easy, though you probably have to buy the standard from ISO to write the code.
Note, the above covers current tractors. Some of the older tractors used an older protocol, God help you if that is your tractor.