In some vehicles it is possible to find J1708 networks that contain some or all data of the vehicle, for example on Volvo, Feigthliner and Renault trucks.

In this article we will discuss the FMS interface J1708 input.  

Characteristics of the J1708 input:

Nominal Input range

-7 – +12 Volts

Baud rate
9600 bits/s
Input protocols
J1708 / J1587

Small explanation of the Protocols:

J1708: Standard used for serial communications between ECUs on a heavy duty vehicle and also between a computer and the vehicle.

J1587: Automotive diagnostic protocol standard developed by the Society of Automotive Engineers (SAE) for heavy-duty and most medium-duty vehicles built after 1985.

On the example bellow, you can see the J1708 wires and J1708 CANgoclick on the schematic of the standard FMS interface wire loom (part no 9164-10):

J1708 input:

  • -J1708 - Orange wire
  • +J1708 - Grey wire
  • J1708 CANgoClick port - J1708/J1587 version port (rigth port)

We always recommend, when possible, to use the J1708 CANgoclick because it eliminates any liabilities and warranty issues.

If the J1708 CANgoclick is not in use, please disconnect it from the FMS interface.