Reply
Super Contributor

Re: ET Coms adapter + and - question?

The connector on the comm adapter cable will not attach to the on-highway service tool connector without the adapter. Both connectors have 9 pins but the pins are different sizes and different locations. The service tool connector is wired the same for all makes of engines. The 1574829 adapter is required.
Contributor

Re: ET Coms adapter + and - question?

Hi Dave,

               Thanks! ok I understand you on that point. But on the onhighway engine schematics it shows a deutsch 9 pin service connector and also the offhighway truck schematics it shows a deutsch 9 pin socket connector but the two have their negative and positive the opisite way around to each other. For instance if they were joined together it would be a  short circuit. So by using the Coms adapter on both with the standard ATA connector(for all engine and truck makes) how come it does not damage the ET Coms adapter internally or does the internal electronics switch it somehow ?    

Super Contributor

Re: ET Coms adapter + and - question?

The truck service tool connector is a standard ATA connector for all engine and truck makes. This standard had not been introduced when the original communication adapter was first used. This is the reason for the 1574829 adapter. Older trucks used a 6 pin in-cab service tool connector which required a 7X1686 adapter.
Contributor

Re: ET Coms adapter + and - question?

Hi Dave,

                  Thanks! But tell me this short adapter cable 1574829 for the onhighway trucks, does it just swap the polarity around on its male and female connector pins so as to protect the Coms adapter from short circuit? If so why is the 317-784 Coms adapter group only sold with the Offhighway cable?  Just wondered?

Super Contributor

Re: ET Coms adapter + and - question?

A 1574829 adapter cable is required to connect the comm adapter to the on-highway service tool connector.
Highlighted
Contributor
Accepted Solution

ET Coms adapter + and - question?

Hi,
Please can someone explain why on the "CAT engine service tool connector" "onhighway trucks" the A terminal is always negative and B positive and on "offhighway trucks" A is allways positive and B negative
yet the same "ET coms adapter" is used?