[WRETAUDIO]

I know for a fact that SPDIF and TosLink can only support up to 48K sample rates and 24 bit audio. Toslink is the optical version of SPDIF. Other than that, they are the same. ADAT is the optical format that can send higher sample rates and bit depths.
I did a term paper on SPDIF and Toslink in college so I'm pretty sure I know those formats.

Your hardware may not be able to send higher than 48K through the ADAT optical connection even though the ADAT standard can allow for that, but it is impossible to send anything higher than 48K through any SPDIF and TosLink connection because that is as high as that standard will go.