cat et help?

I would recommend you don't buy it from all those foreign sites that advertise it. I've heard of a lot of people getting ripped off from them. Don't forget you need more then a laptop with Cat-ET to actually be able to hook up to a truck and use it. You'll need a communicator like the Nexiq- USB link or the Cat Communicator

 

http://nexiq.com/node/3

 

The cheappest is Inline I, but it does not support J1939

Nexiq is a good thing, but I use Inline. Noregon, Deaborn, Eaton, Knorr UDIF, Volvo 88890020 are all RP1210A. But for example Volvo got KWP, K-line for old trucks, UDIF supports all EU protocols, CAT supports CDL, but all they may work with J1587/1708 and J1939

 

CAT Com. adapter supports CDL, so you can use it with non highway engines