Mike

The JetCat cable is NOT a standard phone cable. A phone cable will damage your ECU.

You can buy the cable ends and the crimper to shorten them yourself, but you have to get the correct connectors. I was using the wrong connectors and had some trouble until I got the right ones. The connectors must be for multi-strand wire. The normal phone line connectors are for solid wire.

Make sure you look at a JetCat cable to get the orientation of the connector correct. The connectors on both ends will be crimped on the wire, exactly the same. Notice the color coding on the wire is the same on both ends of the cable.