Heavy-duty diagnostic terms, defined

SAE J1939 is the standard CAN-based communication protocol used by heavy-duty trucks, buses, and off-highway equipment to share engine, transmission, brake, and emissions data on a single wiring bus.

RP1210 is the Technology & Maintenance Council's Windows API for heavy-duty diagnostic adapters. It lets one diagnostic application talk to many vendors' VCIs through a common interface.

SAE J2534 is the pass-through reprogramming standard originally written for emissions-related ECU flashing on light-duty vehicles, now widely used for diagnostics across many vehicle classes.

CAN bus (Controller Area Network) is the differential, multi-master serial bus used by virtually every modern vehicle to let ECUs share short messages without a central host.

UDS (Unified Diagnostic Services) is the ISO 14229 protocol that defines the request and response language used by modern diagnostic and reprogramming tools to talk to ECUs over CAN.

J1708 is the legacy serial bus used on heavy-duty trucks built before roughly 2007, with J1587 as the application-layer protocol carrying engine, transmission, and brake messages.