first time to connect something through an “S/P DIF” (Sony/Philips Digital Interface Format) fibre optic cable with TOSLINK connectors

• https://en.wikipedia.org/wiki/S/PDIF
• http://www.logitech.com/en-roeu/product/speaker-system-z906 – a Logitech “Surround Sound Speakers” system (Z906)
• http://www.logitech.com/assets/36226/z906620-002920006ug403.pdf – the Z906’s User’s Guide
• a Samsung SmartTV

Being connected to both a Mac mini and also the SmartTV, I now have to choose explicitly on the “sound system”, which input to use.