This is a Coaxial/ Toslink (optical/S/PDIF)device! It is used for any device such as a DVD player or a receiver that has only one coaxial digital audio input  that does not a optical connection to it! So this device converts a coaxial signal to a optical signal is sounds crips and clear. If there is any questions please call 1-800-506-9607 the power supply, the optical wire that goes from the cable into the DVD player, receiver, etc. A coaxial cable be included. The company is C2G.