Briefly describe the working principle of OBD2 16pin to J1939 9pin and J1708 6pin cable

Briefly describe the working principle of OBD2  16pin to J1939 9pin  and J1708 6pin cable The OBD2 to J1939 and J1708 cables are devices used for converting and transmitting data between different vehicle communication protocols. The following describes their working principles: protocol analysis OBD2 protocol reception: When one end of the cable is connected to the vehicle's OBD2 interface, it will receive data that follows the OBD2 protocol. The OBD2 protocol is commonly used in passenger cars and has specific data formats and communication rules. The protocol conversion module in the cable will recognize and receive these data frames. J1939 and J1708 protocol reception: If the cable is connected to a vehicle system that supports J1939 or J1708 protocols, the conversion module will also receive data for the corresponding protocol. J1939 is mainly used for CAN bus communication in commercial vehicles, while J1708 is a serial communication protocol adopted by early commercial vehicles.

Data Processing and Conversion Data parsing: The protocol conversion module will parse the received data and extract useful information, such as engine speed, coolant temperature, fault codes, etc. This involves analyzing the format of data frames from different protocols and interpreting the actual meaning represented by the data according to the regulations of each protocol. Protocol conversion: According to the conversion requirements, the parsed data is repackaged in the format of the target protocol. For example, if OBD2 data is to be converted into J1939 data, the conversion module will convert the OBD2 data into a form that complies with the J1939 protocol based on the data frame structure, identifier rules, etc. of the J1939 protocol; Similarly, data conversion from J1939 or J1708 to OBD2 can also be performed. Electrical signal adaptation Signal level conversion: Different protocols have different requirements for electrical signals, such as voltage amplitude, logic level definition, etc. Cables need to convert the signal level to ensure that data can be transmitted correctly in bus systems with different protocols. For example, converting the signal level of the OBD2 interface to a level suitable for the J1939 or J1708 bus. Adjustment of signal transmission characteristics: In addition to level conversion, it is also necessary to adjust the transmission characteristics of the signal, such as rise time, fall time, impedance matching, etc., to ensure that the signal is not distorted during transmission and improve communication reliability. data transmission Bidirectional transmission: This cable supports bidirectional data transmission. It can convert the data obtained from the OBD2 interface and transmit it to the J1939 or J1708 system, or convert the data from the J1939 or J1708 system to OBD2 format and transmit it to the devices connected to the OBD2 interface, achieving data interoperability between different vehicle systems. Buffer and synchronization: During data transmission, in order to avoid data loss caused by mismatched data rates or communication conflicts, cables will set up data buffers to temporarily store and schedule data, ensuring that data can be transmitted in an orderly and stable manner between different protocol systems.