db9

My motherboard on my desktop does not have any serial ports at all, only USB 2 and USB 3 ports. So I read up that the scanner has a mini USB port on the front and a DB9 connecter that connects to the desktop? I'm at a loss here. So would something like this help me...

I can get the front panel serial port to work with the provided adaptor cable, but when I try the rear serial port with a straight-thru cable the radio is not seen. Do I need a null modem cable? P.46 of the manual is not too clear on this port, and they mention a null modem cable. My straight...