According to online information, a J1939 introduction outlines the product’s design and explains how it specifies a differial serial communications bus for inter-connecting ECUs on both heavy-duty and commercial vehicles. The J1939 performs this task by standardizing a hardware and software protocol for sending messages. The J1939 replaces the previous models J1587, J1708, and J1922. Its enhanced capabilities allow for it to be a much better solution for any heavy-duty or commercial system.

The J1939’s Datalink is a half duplex, multi-master, bidirectional network with a network speed of 250K bits per second. Its physical layer is composed a twisted pair of wires with differital signaling technology. J1939 networks rely upon a CAN transceiver which generates a passive signal for a bit value of 1 and an active signal for a bit value of 0. By using passive bits it allows for non-destructive bus arbitration.

This new model outperforms other older models because of its enhanced capabilities. Thanks to new technological developments the J1939 is able to reduce a number of the specific problems previous models faced while still maintaining is highly competitive price point.

When it comes to message destination, the majority of messages defined by J1939 are broadcasted openly as opposed to destination specific. This means that the data is transmitted over the network without a specific destination. This type of technology allows for all devices to use the data without having to specifically request the data. When a message is transmitted to a specific address, the address is included in the CAN identifier allowing for faster receipt.