The HD I/O, HD OMNI, 192 I/O, 192 Digital I/O, and 96 I/O include AES/EBU, S/PDIF, and ADAT digital options. Additionally, the HD I/O with a Digital Expansion card, 192 I/O, and 192 Digital I/O include TDIF digital I/O options. The 96i I/O includes only the S/PDIF digital option.
HD MADI includes both optical and coaxial MADI I/O (for more information, see the
HD MADI Guide).
On HD I/O, HD OMNI, 192 I/O, 192 Digital I/O, or 96 I/O, Pro Tools can receive digital audio from the factory-installed Optical (ADAT) I/O at any time (if it is not set to S/PDIF). However, Pro Tools can only receive digital audio from one of its enclosure [Encl] digital sources—AES/EBU, S/PDIF, or Optical (S/PDIF)—at a time.
Enclosure digital sources come standard with Avid HD audio interfaces and are labelled on-screen as [Encl] versions, to differentiate them from digital inputs and outputs available on the Digital card installed in HD I/O or 192 I/O. For example, the AES/EBU inputs and outputs that come standard in the 192 I/O enclosure are identified as AES/EBU [Encl].
The additional digital ports on the HD I/O, 192 I/O and 192 Digital I/O are TDIF, AES/EBU, and ADAT. Pro Tools can only receive digital audio from one of these ports at a time.
However, inputs on both the HD I/O and 192 I/O enclosure I/O and Digital card can be used simultaneously. For example, on an HD I/O, it is possible to clock off a source from one of the enclosure inputs and have another digital input from the digital ports doing a sample rate conversion, thus having two digital sources.