Hello. I can assure you it can capture Dolby or DTS stream. I use the Phiree U2S (not U2SX, not sure if it makes a difference). There's one toslink/optical in, on the (micro)usb side, and an optical out, on the coaxial side. If you don't record with it, it can passthrough audio from Optical to Coaxial, or Optical to Optical. You need to adjust recording frequency/sample rate in Windows audio panel, in the recording tab, to 16 or 24 bit/48 khz. You also need to use a bitstream accurate/perfect recording tool, like Sony Soundforge, or Reaper. Then, you need to use a software, like BeSplit, to convert (AC3)Wav to AC3 file.
My new ebay store:
https://www.ebay.com/str/retroeverdrive
I recommend Sony SoundForge 9 instead. You will also need Asio4All...
https://www.videohelp.com/software/Besplit
http://forum.doom9.org/showthread.php?p=146873
BeSplit -core( -input input.wav -prefix C:\USERS\YourNAME\Desktop -type ddwav -fix )
*Edit:*
I'm selling the unit which have a toslink input on the micro usb side, not like the *new* U2SX units. I will add listings in my ebay store.
https://www.ebay.com/itm/USB-audio-C...X/114171898547