Avid HD OMNI Preamp, I/O, and Monitoring Pro Tools HD Series Interface - Manual (Page 17)

Chapter 2: HD OMNI Overview 13
OPTICAL IN and OUT (1 and 2)
HD OMNI provides two sets of eight-channel
Optical (TOSLINK) input and output. The Opti-
cal I/O on HD OMNI supports up to 24-bit au-
dio, at sample rates up to 192 kHz. The number
of available Optical input and output channels
varies with sample rate as described below:
ADAT Optical
At sample rates of 44.1 kHz and 48 kHz, Optical
Port A provides eight channels of audio input
and output. Optical Port B is unused for input,
but on output it mirrors Optical Port A (chan-
nels 1–8).
S/MUX 2
At sample rates of 88.2 kHz and 96 kHz
(S/MUX 2), each Optical port provides four
channels of audio. Optical In and Out 1 send
and receive channels 1–4, and Optical In and
Out 2 send and receive channels 5–8.
S/MUX 4
At sample rates of 176.4 kHz and 192 kHz
(S/MUX 4), each Optical port provides two
channels of audio. Optical In and Out 1 send
and receive channels 1 and 2, and Optical In
and Out 2 send and receive channels 3 and 4.
Optical (S/PDIF)
Either set of Optical I/O ports can also be used
for two-channel Optical S/PDIF input and out-
put with support for sample rates up to 96 kHz.
HD OMNI can receive two channels of Optical
S/PDIF when operating at sample rates of 176.4
and 192kHz, but sample rate conversion (SRC) is
automatically enabled for this feature. The
Opti-
cal (S/PDIF) option can be selected in the
Pro Tools Hardware Setup dialog.
About Lightpipe-Compatible Devices
Lightpipe is an industry standard, eight-channel
optical digital audio connection created by Ale-
sis. Lightpipe is found on many devices, includ-
ing Optical (ADAT) decks, modular digital mul-
titracks (MDMs), sound cards, A/D or D/A
converters, and digital mixing consoles.
DigiLink Mini Ports
PRIMARY PORT
Use the PRIMARY PORT to connect HD OMNI to
your Pro Tools|HD system using a DigiLink Mini
cable with a DigiLink Mini to DigiLink adapter
cable (included), or to your Pro Tools|HD Native
system using the DigiLink Mini cable (included
with your Pro Tools|HD Native system).
The PRIMARY PORT can send and receive up to
32 channels to and from a Pro Tools|HD card.
Channels 17–32 (if active) are passed through to
the EXPANSION PORT. However, note that HD
OMNI only provides up to eight channels of in-
put and output.
When using HD OMNI in a system with multi-
ple interfaces, it will provide eight channels of
input and output on Pro Tools channels 1–8 or
17–24 depending on whether or not HD OMNI
is connected directly to a Pro Tools|HD card, or
whether it is connected to the Expansion port of
another Pro Tools|HD peripheral (such as an
HD I/O).
When using S/MUX, only the first optical
port can be used to synchronize to external
clock.