Universal Audio Apollo Twin - Manual (Page 27)

Apollo Twin Hardware Manual Chapter 3: Controls & Connectors 27
(19) Optical In
This is a TOSLINK input for connection to other gear with an optical ADAT or S/PDIF
output.
Note: The protocol to be used (ADAT or S/PDIF) is specified in the Interface panel
of the Console Settings window.
(20) Thunderbolt Port
Connect the Thunderbolt cable (not included) here. A Thunderbolt connection to the host
computer is required to use all Apollo Twin features and UAD Powered Plug-Ins.