The JetCat ECU needs a PWM signal the same as an R/C servo to operate. This connects via a 3 pin connector on the ECU. The easiest way to do this from a PC is to use a USB servo controller. There are several companies who make these or you can build and program one using an Arduino type microcontroller.

Here is one company who make ready built servo controllers but there are several.https://www.pololu.com/category/102/...vo-controllers

Hope this helps?

Malcolm