What you see there by the “-“ and “+†is actually denoting digital (DVI-D) and digital plug analog (DVI-I). The DVI receptacle with the “-“ is digital only, it will not accept an analog signal. The 4 pins located around the ground tab are for analog RGBHV. Your device requires a digital only signal. The dongle you have is a DVI-A adapter changing an HD15 VGA to a DVI-A or vice versa. It will not work at all for digital. If your PC has a DVI card then buy a DVI-D cable and connect it. This cable will not have the 4 pins around the ground tab. The Digital DVI signal is the same for all devices; you may have dual link or single link capability. Probably single link since dual link isn’t used much in the HT market. A dual link cable will perform all single link functions, just 3 TMDS channels are not used.