I am trying to interface to a truck's in-vehicle network using a legacy computer. I know nothing about in-vehicle network standards.
We bought a Dearborn Group DPA III/i to communicate via a serial line.
But I think I bought the wrong standards document (SAE j1939-71) and I am trying to be absolutely sure that I buy the right one this time.
The truck is a 2000 Sterling L7500. According to Dearborn, the DPA is indicating the J1708 protocol when connected to the truck. But I think that J1708 is the physical layer. I need a document that specifies the data layer. I have been advised that the correct standards document might be J1587. I am not sure how to confirm that. I have not found a technical assistance line a Sterling where I can confirm that this specific model or VIN uses J1587.
If anyone could provide the MID and PID for RPM or something every truck should report, then I could try it.