Used to program the Original ECT modules using a PC Serial Port and communication software. Programming is only needed if the standard ECT module programming is not a good match for your car or if you just want to change the way your temperature gauge is operating. Detailed programming and troubleshooting documents are available in the Manuals tab for your specific ECT module.
NOTE - Make sure you buy the correct cable; this one ONLY works on the Original ECT module, which uses a separate 2-wire connector for programming. If your ECT module has screw terminals then you need to buy the Programming Cable for ECT-2.
Serial ports and communications software (Hyperterminal) were standard on Windows XP computers (common when the ECT module was first developed) but you can still program the ECT module using a newer win7 or Win 10 machine by purchasing an inexpensive USB-to-serial adapter. These can be found on ebay for $2 or $3 delivered. I've purchased a few to test and found they work perfectly.