SAEJ1850

SAE J1850 is a standard developed by the Society of Automotive Engineers (SAE) for the communication protocol used in automotive networks. It is primarily employed in older vehicles, particularly those manufactured in the late 1980s and early 1990s. The standard defines the physical and data link layers of the OSI model, specifying the electrical characteristics, signal timing, and data framing for communication between electronic control units (ECUs) in a vehicle.

SAE J1850 exists in two primary variants: SAE J1850 PWM (Pulse Width Modulation) and SAE J1850 VPW (Variable Pulse Width). The PWM variant uses a single wire for communication, with the width of the pulse representing the data bits. The VPW variant, on the other hand, uses two wires, with one wire representing the data and the other representing the clock signal.

SAE J1850 has been largely superseded by more modern protocols such as CAN (Controller Area Network) and LIN (Local Interconnect Network), which offer higher data rates, better error detection, and more robust communication capabilities. However, SAE J1850 remains relevant in the automotive industry for maintaining compatibility with older vehicles and for certain specialized applications where its simplicity and low cost are advantageous.