optika >> stereo analog
https://www.gme.cz/digitalni-opticky-spdif-coax-prevodnik-na-stereo-rca-analog-audio-a-3-5mm-jack
optika >> 5.1 analog
https://www.aliexpress.com/item/UNSTINCER-5-1-CH-Audio-Decoder-SPDIF-Coaxial-to-RCA-DTS-AC3-Digital-to-5-1/32818460809.html