Most engine builders' software prefers to use a serial port to talk to the engine. Yes USB and really ancient printer ports can be used. They work most effectively though the 232 connection on a serial port.
I really like the expansion port 3. It used to be pretty much standard on the HP laptops and now they force you into a higher end model if you want this feature. The QuiickDock is the greatest but I don't see a traditional DB serial port on mine if that is what is needed.
