Analysis of J1939 and J1708 Cable Conversion Technology

In the automotive electronics industry, J1939 and J1708, as two important communication protocols, each play a crucial role. With the development of technology and the upgrading of vehicles, it is sometimes necessary to connect devices based on J1939 protocol with systems based on J1708 protocol, which involves J1939 and J1708 cable conversion technology. This article will delve into the principles, applications, challenges, and solutions of this conversion technology.

1、 Overview of J1939 and J1708 protocols

J1939 protocol is a communication standard based on CAN (Controller Area Network) bus, widely used in heavy vehicles, agricultural vehicles, industrial machinery and other fields. It supports high-speed data transmission, has good scalability and flexibility, and can meet the communication needs between multiple Electronic Control Units (ECUs) in complex vehicle systems.

In contrast, the J1708 protocol is a Society of Automotive Engineers (SAE) standard based on RS-485, mainly used for serial communication in agricultural vehicles, commercial vehicles, and heavy machinery. It defines a 2-wire 18 gauge cable with a communication rate of 9600 bit/s during operation and a length of up to 40 meters. The J1708 protocol is more common in older vehicle systems, but with the popularity of CAN bus, J1708 has gradually been replaced by J1939.

2、 Principle of J1939 and J1708 Cable Conversion Technology

The core of J1939 and J1708 cable conversion technology is to achieve data conversion and transmission between two different communication protocols. This typically requires a specialized converter that can receive J1939 protocol packets, convert them to J1708 protocol data format, and then send them to the target device via J1708 cable. Similarly, the converter can also receive data from the J1708 protocol and convert it into J1939 protocol packets for transmission.

The converter typically consists of two main parts: a protocol conversion module and a data transmission module. The protocol conversion module is responsible for parsing and converting protocol headers, data fields, and checksum information of data packets; The data transmission module is responsible for transmitting data on the CAN bus and RS-485 bus.