The cable on the left in that picture is an HDMI to HDMI cable. It carries both DIGITAL VIDEO and DIGITAL AUDIO. However, some devices or configurations you may only want to use HDMI's video stream. You may want to hook up an analog stereo, for example, or a set of PC speakers (just because it's a digital connection doesn't mean your TV's built in speakers will outperform your 2.1 or 5.1 sound system with powered subwoofer). The cord on the right solves this problem by providing ANALOG AUDIO (red and white cables for 2 or 2.1 channel connection) and DIGITAL OPTICAL AUDIO (fiber-optic LED and connector for 5.1 Dolby Digital connection to a Dolby Digital surround sound amplifier/decoder or speaker set). Also, not all HDMI supporting devices support sound through HDMI, some devices only use it for video. Devices (like my w2007 monitor) using HDMI to DVI can only take video, as the end format is DVI, which doesn't support audio.