DigiDesign 192 I, Manual

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Chapter 2: 192 I/O Overview 9
Enclosure Connectors
The right half of the back panel of 192 I/O fea-
tures a set of non-removable connectors that are
mounted to the enclosure.
These connectors feature two additional chan-
nels of AES/EBU I/O and another eight channels
of Optical I/O. These ports appear on-screen in
Pro Tools as AES/EBU [Encl], and
Optical (ADAT) [Encl]. The reference to the en-
closure [Encl] differentiates the chassis-
mounted ports from the I/O of the same types
on the Digital I/O Card.
Also mounted on the enclosure are two chan-
nels of S/PDIF I/O on RCA connectors, Loop
Sync, External Clock, and ports for attaching the
192 I/O to Pro Tools|HD cards and other audio
interfaces.
AES/EBU [Encl]
These are balanced, three-conductor XLR con-
nectors that accept and output a stereo, 24-bit
AES/EBU digital data stream. These two ports
support up to 96 kHz sample rates. The enclo-
sure ports do not support dual-wire mode (re-
quired for 176.4 kHz and higher sample rates),
or provide real-time sample rate conversion (use
the ports on the Digital I/O card for these fea-
tures).
S/PDIF Stereo I/O
These are unbalanced, two-conductor RCA jacks
that accept and output a stereo S/PDIF digital
data stream. S/PDIF supports up to 24-bit audio,
at sample rates up to 96 kHz.
Optical (ADAT) [Encl]
These are Optical ports that accept up to eight
channels of Optical (ADAT) input and output,
or two channels (stereo) optical S/PDIF input
and output. Optical (ADAT) mode supports sam-
ple rates up to 48 kHz. In TOS-Link mode, sup-
ports two-channel Optical input and output at
sample rates up to 96 kHz. This port does not
feature real-time sample rate conversion.
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 consoles.
LOOP SYNC In and Out
Loop Sync is a dedicated clock loop for synchro-
nizing multiple Pro Tools|HD peripherals to-
gether (multiple audio interfaces, and/or a
Digidesign SYNC I/O and one or more audio in-
terfaces). Loop Sync uses a word clock signal
based on sample rates of either 44.1 kHz or
48 kHz. As sample rate increases in the system,
Loop Sync continues to operate at a base rate of
44.1 kHz or 48 kHz, depending upon the higher
rate.
The Loop Sync In and Out ports are standard
BNC connectors that output a 1x Loop Sync
clock signal. Loop Sync should only be used to
chain multiple Pro Tools|HD peripherals to-
gether.