The function of J1939 to J1708 cable

The function of J1939 to J1708 cable

J1939 protocol

The J1939 protocol is a high-speed serial communication protocol developed by SAE (Society of Automotive Engineers) for commercial vehicles, based on CAN (Controller Area Network) bus technology. It adopts a multi master communication method, with a data transmission rate of up to 250kbps, and features high bandwidth, high reliability, and strong anti-interference ability. The J1939 protocol defines a complete set of communication rules and data formats, which are widely used for communication between various electronic control units (ECUs) such as engine management, transmission control, and braking systems in modern commercial vehicles. It can efficiently transmit large amounts of real-time data.

J1708 protocol

The J1708 protocol is an early commercial vehicle communication protocol developed by SAE. It is a protocol based on single channel, low-speed serial communication, with a data transmission rate of approximately 9600bps. J1708 adopts a master-slave communication mode, where there is only one master node in the communication network and the rest are slave nodes. This protocol was widely used in early commercial vehicle diagnosis and monitoring systems, and many older commercial vehicle electronic systems still rely on the J1708 protocol for data transmission and communication.

The function of J1939 to J1708 cable

Realize compatibility between old and new systems

With the continuous development of automotive technology, most newly produced commercial vehicles adopt the J1939 protocol, while some old diagnostic equipment, monitoring systems, or other ancillary devices may still be based on the J1708 protocol. The J1939 to J1708 cable serves as a bridge between these new and old systems, enabling vehicles based on the J1939 protocol to communicate and exchange data with devices based on the J1708 protocol, avoiding issues such as device unavailability or high upgrade costs caused by protocol incompatibility.

Data Conversion and Transmission

There are significant differences between J1939 and J1708 protocols in terms of data format, communication speed, and communication methods. The J1939 to J1708 cable integrates a specialized protocol conversion module internally, which can convert J1939 protocol data frames into data formats recognized by J1708 protocol, and vice versa. At the same time, it can also perform appropriate rate matching and signal conditioning on data, ensuring accurate and stable transmission between devices with two different protocols.