Optical audio works with one, but NOT two Toslink keystone couplers?

[WAZ]

So to avoid a long description, I whipped up an awesome diagram of the problem I'm having.

Long story short, I'm running HDMI, USB, and digital audio (optical cable) from my PC downstairs to my TV upstairs, but I can't get the audio to work when using these keystone couplers in wall plates:

http://www.monoprice.com/products/p...=10426&cs_id=1042610&p_id=8729&seq=1&format=2

I've tried swapping cables, using both keystone couplers in each position, etc -- so I know both couplers and all 3 of my optical cables work fine. I can run audio from my PC to receiver using ANY 2 cables and EITHER coupler. But once I introduce a second coupler and 3rd cable, I get no audio. Note that I DO still get the red light coming through all 3 cables, so it appears there's still a signal -- it's just not producing audio.

Any help would be great. Thanks!

 

[WAZ]

Ok, nevermind for now. I think adding that third cable just exceeds the max allowable length for the digital audio signal, so it's losing signal strength before it gets to the receiver. Ordered a Toslink signal amplifier and will also try some shorter cables, and that SHOULD take care of it.