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Home » JCOM1939 Monitor – Download, Documentation, and other Resources » JCOM1939 Monitor – Frequently Asked Questions

JCOM1939 Monitor – Frequently Asked Questions

This page provides a comprehensive collection of frequently asked questions about the JCOM1939 Monitor Software, SAE J1939, and the CAN Bus, offering clear and concise answers to common inquiries.

FAQ frequently asked questions

Having Trouble Receiving J1939 PGNs

We acknowledge that some users may experience issues when trying to see SAE J1939 data traffic while connecting our gateway ...

FAQ frequently asked questions

Why Are Termination Resistors Needed?

A Controller Area Network (CAN) requires termination resistors to ensure signal integrity, prevent reflections, and maintain proper bus impedance. Here’s ...

J1939 Diagnostics Made Easy: How Modern Scan Tools Simplify Diesel Engine Troubleshooting
J1939 Diagnostics Made Easy: How Modern Scan Tools Simplify Diesel Engine Troubleshooting
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For diesel truck owners — whether you’re running a heavy-duty rig for work or simply maintaining a robust personal vehicle — having the right diagnostic...
DEF Sensor Simulator Explained: Background, Function, and DIY Assembly Guide
DEF Sensor Simulator Explained: Background, Function, and DIY Assembly Guide
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Please consider! The DEF Sensor Simulator is not an off-the-shelf device. It was originally created by a team of automotive engineers as a proof-of-concept solution...
Why a Ground Connection Matters on a CAN Bus (And How to Wire It Correctly)
Why a Ground Connection Matters on a CAN Bus (And How to Wire It Correctly)
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When working with the Controller Area Network (CAN) bus—whether in automotive, industrial automation, robotics, or embedded systems—you’ll quickly notice that most CAN connectors include a...
Unlocking J1939 Telematics: Teensy 4.1 Triple CAN Bus Board with Ethernet and GNSS
Unlocking J1939 Telematics: Teensy 4.1 Triple CAN Bus Board with Ethernet and GNSS
November 20, 2025
In the heavy-vehicle, mobile-machinery and industrial equipment world, the CAN bus remains a workhorse for on-board networks. But merely having physical CAN isn’t enough: what...
Understanding SPNs and FMIs in J1939: A Simple Guide for Beginners
Understanding SPNs and FMIs in J1939: A Simple Guide for Beginners
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If you’re learning SAE J1939, you’ll quickly run into two acronyms that show up everywhere—in diagnostic messages, simulation tools, engine logs, and OEM documentation: SPN...

J1939 Diagnostics Made Easy: How Modern Scan Tools Simplify Diesel Engine Troubleshooting
J1939 Diagnostics Made Easy: How Modern Scan Tools Simplify Diesel Engine Troubleshooting
December 8, 2025
For diesel truck owners — whether you’re running a heavy-duty rig for work or simply maintaining a robust personal vehicle — having the right diagnostic...
DEF Sensor Simulator Explained: Background, Function, and DIY Assembly Guide
DEF Sensor Simulator Explained: Background, Function, and DIY Assembly Guide
November 25, 2025
Please consider! The DEF Sensor Simulator is not an off-the-shelf device. It was originally created by a team of automotive engineers as a proof-of-concept solution...
Unlocking J1939 Telematics: Teensy 4.1 Triple CAN Bus Board with Ethernet and GNSS
Unlocking J1939 Telematics: Teensy 4.1 Triple CAN Bus Board with Ethernet and GNSS
November 20, 2025
In the heavy-vehicle, mobile-machinery and industrial equipment world, the CAN bus remains a workhorse for on-board networks. But merely having physical CAN isn’t enough: what...
Heavy Duty Truck Systems Explained: A Deep Dive into the Top Diesel Technician Textbook
Heavy Duty Truck Systems Explained: A Deep Dive into the Top Diesel Technician Textbook
November 18, 2025
If you’re looking to dive deep into the world of medium- and heavy-duty trucks—whether as a technician, a fleet maintenance manager, or a student of...
Unlocking the Engine Room: The ANCEL HD601 J1939 Truck Scanner for Heavy-Duty Diagnostics
Unlocking the Engine Room: The ANCEL HD601 J1939 Truck Scanner for Heavy-Duty Diagnostics
November 15, 2025
Maintaining and troubleshooting heavy-duty trucks requires tools that go far beyond a basic automotive OBD-II reader. Whether you work with Freightliner, International, Paccar, Detroit Diesel,...
INLINE Cummins adapter with SAE J1939/J1708 support for fast, reliable PC-based engine diagnostics
INLINE Cummins adapter with SAE J1939/J1708 support for fast, reliable PC-based engine diagnostics
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If you’re working with a Cummins heavy-duty engine, you already know the power and reliability these machines deliver. But to keep them performing at their...
SAE J1939 250k/500k Baud Rate Converter with Silent Mode Support – A Game-Changer for Modern and Legacy Vehicle Integration
SAE J1939 250k/500k Baud Rate Converter with Silent Mode Support – A Game-Changer for Modern and Legacy Vehicle Integration
November 5, 2025
A recent internal market study by Copperhill Technologies uncovered a surprising but critical shortcoming across all commercially available SAE J1939 baud rate converters: none of...
Bringing Diagnostic Clarity to Lithium-Ion Batteries in Rail
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Rail is in the midst of a big energy storage shift: away from lead-acid batteries and toward lithium-ion. The reasons are persuasive: lithium-ion offers higher...
Teensy 4.1 Triple CAN-Bus Board with Ethernet: Bridging CAN Networks and IoT
Teensy 4.1 Triple CAN-Bus Board with Ethernet: Bridging CAN Networks and IoT
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The Teensy 4.1 Triple CAN-Bus Board with Ethernet is a new product from Copperhill Technologies, expanding our lineup of CAN bus and IoT development tools....
Arduino Due SAE J1939 Programming Kit: Complete Solution for CAN Bus Development
Arduino Due SAE J1939 Programming Kit: Complete Solution for CAN Bus Development
August 26, 2025
Looking to take your CAN-bus and SAE J1939 projects to the next level? Whether you’re building a data logger, protocol converter, or a full-blown J1939...