Where are you getting your signal from, a cable box, Blu-Ray, PC, or directly from your TV? If it's only from your TV and you have no digital audio output (co-axial or optical), then you're out of luck! If you have a cable box or any other digital source (blu-ray) feeding video and audio into your TV, use your TV as a video monitor and connect the optical or digital co-ax (orange) to the decoder, which outputs an analog signal to your surround amps. This unit is only for one source at a time, so you'll have to manually connect each source you want to listen to and simply change to the desired video input on your TV to see it. Easier (more expensive) solution for multiple sources is to get an HDMI compatible A/V receiver. The receiver will have multiple digital inputs with multiple choices (HDMI, Optical, Co-ax). In order to take advantage of the latest and greatest multi-channel surround formats, you need an HDMI compatible system. HDMI combines audio and video, whereas TOSLINK optical and Co-ax are audio only. If your TV has HDMI, choose another decoder with an HDMI input. Hope i helped!
Without a digital output you can't get digital surround sound from the TV.
You can't convert analog 2 channel to digital 5.1 channel.
You could connect all your HDMI sources to an external HDMI input selector with audio extraction. That will have a digital audio output you can connect an optical to 5.1 analog converter. You will need to control the volume with the speakers since this is always a fixed level output.
for the hdmi compatible a/v reciever, i will use hdmi cable from tv to the reciever and then reciever to subwoofer? and then what do you mean "if your tv has hdmi, choose another decoder with an HDMI input."?