Do you mean by spec or you happen to have two connectors and a cable? In the case of the latter it might be possible if you used two very different wavelengths of light and the appropriate detector or modulate the data at different frequencies. I could be wrong though.
toslink is just the optical version of S/PDIF, the protocols are identical. One side transmits the other recieves, that is all that can occur bi-directional communication is not possible. I've never seen a mic that has an input, or a speaker that has an output, could you explain what you're trying to do a bit better?
i decided only to use TOSLINK out put for TV's and media players
its for a computer build
i am taking a electronics course in september
ATM im planning everything which can be verified without electrical knowledge out
i know but i don't think that at all, lets just say (as an example) a LED and button cell,
if i worked out (with help maybe) tha the longer leg on the LED goes to positive and the small leg on the LED goes to negative i have made sure that it will work before building it,
which is what i'm going with the sound chip but not including the other components (like resistors) yet