Optical vs Ultra Rendu.

Then to add more confusion, the wiring diagram on the Small Green Computer site show a simple fiber ethernet cable going from the router to the optical Rendu.

https://www.smallgreencomputer.com/collections/recommended-solutions/products/systemoptique-server-player-combo-sonictransporter-i5-or-i7-cdr-opticalrendu-4-port-gigabit-switch-with-fiber-port-and-power-supplies

So, what is all the extra hardware seen in this Hans Beekhuyzen video starting around 2:05. Such as the SFP media converters. What is the difference between these two set ups and will there be any difference in SQ? 

https://www.youtube.com/watch?v=q0A0l6keKTg

SGC - That is because the switch has an optical output

OK, I think I get it, thanks singingg!

I have a BlueSound Node 2i.  Would this hook up to my BlueSound?  Has anyone done a true blind test?  This would require someone to change the connections to do an A/B comparison without the listener knowing the source by doing a random switching back and forth.  Try to stump the listener and then tell them which connection was what.  Some of these expensive add on little noticeable difference.  Kind of like splitting hairs in my opinion.  Which is more noticeable, upgrading speakers or amplifiers or using this add on?

the central idea of the optical rendu is to convert the audio signal into optical and then back to electrical just before sending it to the dac, such that any electrical noise on the ethernet fed electrical line is left behind

so of course, using any properly functioning fiber media converter to do the job will accomplish the objective

of course it is then key, on the receiving end of the signal that there be very quiet, noiseless power supplies used, so that new noise from such things as switch mode power supplies are then re-introduced into the music bearing signal