CAT Comm III Adapter

by CAT

CAT Comm III Adapter


SKU 538-5051-TFC

The latest generation of the CAT Communication Adapter group, and this replaces the CAT Comm Adapter II. This is the only recommended communication device for CAT and the only datalink device that will allow you to properly communicate with a CAT engine on dual datalinks. This function is needed for some CAT ET (Electronic Technician) functions. This is also the only cable that will communicate with CAT off-road equipment when used in conjunction with the CAT ET software. This is a genuine CAT, not a clone or knock-off.


About the CAT Comm III Adapter

The "old" CAT Comm 3 (Part # 466-6258 & 317-7484) has been replaced with this newer CAT Comm 3 (part # 538-5051). With new firmware and new cables, this CAT adapter is better than ever!

This item is manfuactured in Canada, and it is the 100% genuine item, not a clone/knock off!


  • CAT Comm Adapter III (part # 538-5051)
  • CD for installing the drivers
  • USB Cable (From device to your computer)
  • J1939/J1708 Cable (from device to your truck)
  • Hard Shell Case with foam inserts

There are other tools that perform CAT off highway diagnostics. Please look at our TEXA Construction and Off Highway diagnostic tool.

Return Policy

Easy Returns

When you buy from Diesel Laptops, we want to make sure you're happy with your purchase. You may return this product within 30 days of delivery, with a small 15% restocking fee. It's part of how we keep things fair for everyone.

For more details, please visit our Return Policy page below.

View Return Policy

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If you have any questions about this or any other product, please don't hesitate to contact one of our Diesel Laptops experts at (888) 983-1975 or by clicking below!

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Customer Reviews

Based on 9 reviews
Kent White

CAT Comm III Adapter

John (Canada)
Great price!

Received the Cat comm 3 quickly and the item was new as described. Have tested it with Cat ET, Cummins Insite and Detroit DDL to date.
Would like to add one thing to the review as I did not see it in the others I read before purchasing. If looking to connect to on-highway, adapters 507-1011 is required for the 9 pin (J1939) connection and 7X-1686 for 6 pin (J1708). They are also available from seller but I was unaware and had to order them after receiving. No fault of the seller. Highly recommend.

Abdullah Muhammad
cat comm adapt 3

fast delivery and it was exactly what i ordered

thank you

Jesse swartz
Legit cat

Package arrived fast and it was exactly what I ordered

Dragomir Dragolov