How to Adjust Volume
When using Digital Optical: This can ONLY be done if your headphone/speaker supports AVRCP (most of the ones with volume adjustment buttons do.) You may either adjust the volume via the "+" and "-" buttons on Audikast Plus or via the volume adjustment controls on your headphone / speaker.
When using AUX (3.5mm) or RCA: You may adjust the volume directly via your TV / AV Receiver's remote control. If your headphone / speaker has a built-in volume adjustment system, you may use those as well.