Briefly describe the working principle of J1939 to OBD2 cable

Briefly describe the working principle of J1939 to OBD2 cable

The working principle of J1939 to OBD2 cable is mainly through the built-in protocol conversion chip, which converts signals that comply with J1939 protocol into signals that can be recognized by OBD2 protocol, achieving communication between two different protocol devices, as follows:

Signal reception and analysis: One end of the cable is connected to the J1939 interface of the vehicle, which is connected to various electronic control units (ECUs) of the vehicle through the J1939 bus. When the vehicle is running, each ECU will send corresponding signals on the bus according to the J1939 protocol based on its own working status and sensor input information. The protocol conversion chip in the cable first receives these J1939 signals and parses them to extract the vehicle operation data contained therein, such as engine speed, water temperature, fault codes, etc.

Protocol conversion: The protocol conversion chip repackages and encodes the parsed J1939 data according to the format and rules of the OBD2 protocol. For example, the data representation, transmission rate, and verification method in J1939 protocol are different from those in OBD2 protocol. The conversion chip will convert the data accordingly to meet the requirements of OBD2 protocol, so as to communicate with OBD2 devices.

Signal transmission and transmission: After protocol conversion, the data is sent to the OBD2 interface through the other end of the cable, which can be connected to various devices that comply with the OBD2 standard, such as diagnostic instruments, data collectors, etc. These devices are capable of recognizing and reading converted signals to obtain relevant information about the vehicle, enabling functions such as fault diagnosis and data monitoring of the vehicle.