This Bigstuff Bigcomm cable has the commport connector on one end and a serial connection on the other end. It is 25′ in length and is guaranteed to connect your GEN3 ECU to your laptop.
If your laptop does not have a serial connection make sure to get the USB to serial cable adapter here -> https://bigstuff3efi.com/product/usb-to-db9-rs232-adapter-cable-6-ft/