J1708 Interpreter – firmware version 2.0

Quantity Pricing

The following are the unit prices, as you vary the quantity purchased:






All prices are in Canadian dollars. We use the total number purchased (ELM325P + ELM325SM) for the calculation.


With the advent of electronic engine controls, many vehicles also adopted some form of diagnostic tools to help monitor their operation. As more modules began to be used in vehicles, there was also a need for the devices to share information rather than each independently obtain this from separate sensors.

In the 1980’s, the SAE J1708 standard was created to provide a specification for a common data bus to be used in heavy duty vehicles. It used RS485 wiring (already proven to be reliable in noisy environments), and a UART-based low speed data format. The SAE J1587 standard followed a few years later to describe the mechanism by which messages and data should be sent between vehicle modules.

The ELM325 allows a PC or similar device to be used to monitor and query devices on a J1708 data bus, using simple commands that can be sent from almost any terminal program. It is able to work with either the J1587 or the J1922 data formats.


  • Diagnostic trouble code readers
  • Heavy duty vehicle scan tools
  • Teaching aids
  • ECU Simulators


  • Supports both SAE J1587 and J1922
  • High speed RS232 interface
  • Works with standard RS485 transceivers
  • Fully configurable with AT commands
  • Wide operating voltage range (1.8 to 5.5V)
  • Low power CMOS design

Connection Diagram

( PDIP or SOIC, top view )

Block Diagram

ELM325 block diagram


The ELM325 data sheet (ver B, 197K):

pdf icon

The ELM325 data sheet iBook (3.2MB):


Although the v1.0 integrated circuit is no longer available, we have kept the data sheet for it on the web site. Just go to the Products/Data Sheets page.

Alternative Labelling

To help us meet demand, Microchip Technology has been programming and labelling some of the ELM325 chips for us. These ICs may look different, but are functionally identical. You may receive ICs that look like those shown above, or as shown below. The differences are only in appearance:

sku: ELM325Psku: ELM325SM

Related Products

We do not currently offer any other devices that support the SAE J1708 standard. There have been a large number of requests for a combination J1939 – J1708 device and we are considering that, but at present can not provide an estimate as to when that might be available.