The Razer Tomahawk Gaming Desktop comes with two 3.5 mm jacks as shown below. The regular 3.5 mm jack (H) just below the power button. You can use this as a 3.5 mm jack which will support audio in/out. The other 3.5 mm jack (F) is next to the HDMI port also an Optical Out port jack. This will support Audio output with 3.5 mm jack with no mic function. The optical out port is a Mini-TOSLink Port.
The image below shows the Mini-TOSLINK (left) which is a standardized optical fiber connector that is smaller than the standard square TOSLINK (Right) connector commonly used in larger consumer audio equipment as an alternative to Coaxial and HDMI cables. The Mini-TOSLINK looks similar to the 3.5 mm stereo minijack. Adapters are available to connect a full-size TOSLINK plug to a mini-TOSLINK socket.
