All right, I was joking because this Toslink level adjustment is massively asked for on the Internet by many users who want to get their Apple remote working on a, Motu, Apogee, RME, etc. D/A converter but they always obtain empty replies like "it intended not to work" etc. They don't care that "it intended not to", they just want their audio investment just being usable without running across the room to turn knobs...
I understand very well that someone who have got a high quality sound system want to get the volume adjusted via kb or Apple remote. I now this problem because my power amp is two rooms far from my sofa ! I simply can't adjust the volume from there because I do not hear what is going on in the living ! As I use a Crown Macro Reference amp (2 x 1500 W, 120 dB s/n, Damping Factor 20.000) and a pair of 4343 JBL Pro Studio Monitor (4 ways, 106 kg each) I didn't want to listen music on a cheap chipset with a 90dB signal/noise (s/n) ratio for the only reason my Mac is not able to control the toslink level from keyboard or remote, that is completely crazy ! I also didn't want to switch to Windows (whatever the toslink is well handeld and good utilities are available).
So, each time I surf the Internet and see someone who ask this question and get this empty "techno-ideological" speech ("Toslink is not adjustable", "You must not adjust it", and so) as an answer instead of the waited for solution, I post a simple and "operative" way to help him get rid of that 🙂
If you want to get some details about s/n ratio, dynamic range, overhead, and so on, you can have a look to Bob Katz "Mastering Audio" (easy to read, IMO the best for catching the state of the art in sound). You will also find some pdf litterature from Katz on the net.
Briefly, the point in sound is to keep the signal far from noise and below clipping. That is easy if you set your toslink at 24/96 because in nearly any case you will get a range that will widely exceed (by several hundreds) the specs of a "good amp" (about 100 dB s/n). That is not true for the analog output, badly affected by the electromagnetic pollution of the environment (motherboards, chipsets, network adapters and graphic cards). This is why some users seek to use optical link at high rates that can carry a mathematically perfect signal to the D/A converter (far from any noisy motherboard, and near by the power amp input XLR).
English is not my 1st language ! How did you get it !? 🙂))