YAMAHA receiver not seeing optical input

[SolarSystem]

I am trying to connect our TV to the surround sound system through a YAMAHA RX-V565 receiver.

The TV only has optical output, so got myself a cable and plugged it in. However, no sound is coming out of the speakers.

I tried the cable through my computer monitor, since it has HDMI in and optical sound output, but that also failed. I can clearly see the light coming through the cable, so there is a signal of some sort going through it.

The receiver, however, reproduces only silence.
It DOES work fine for input from our CD player through RCA cables, and the built-in radio works fine too.

Help?

 

[MDS]

Two things to check first:

1. On the TV, you may have to go into its menus and turn the internal TV speakers off to enable the digital audio output.

2. On the receiver, you have to assign the digital inputs to an input selector. For example, if you want to hear the sound coming from the TV when you select say 'Cable' input on the receiver and the optical cable from the TV is going to optical input 1, then you need to assign 'Cable' to optical input 1.