Specifications

192 Digital I/O Guide 8
Digital Formats
AES/EBU Each card contains DB-25 connectors
for eight channels of AES/EBU I/O. Each of the
four paired channels of AES/EBU on each card is
a balanced three-conductor signal that supports
single wire I/O up to 96 kHz and dual wire I/O
up to 192 kHz.
For AES/EBU input, each Digital I/O card can ac-
cept up to 192 kHz and downsample the infor-
mation to any other supported sample rate.
Dual-Wire mode uses two pins to transmit a sin-
gle channel, or four pins to transmit two chan-
nels of digital audio. Dual-wire is only sup-
ported via the DB-25 AES/EBU connector.
Four channels of AES/EBU I/O are available at
192 kHz per card or eight channels using both
AES/EBU connectors.
TDIF Each card contains DB-25 connectors for
eight channels of TDIF input and output. This
port conforms to standard eight-channel TDIF
pinouts. See Appendix B, “Pinout Diagrams for
the DB-25 Connectors.”
Optical (ADAT) Each card contains a pair of ded-
icated, eight-channel 24-bit capable Optical
ports for input and output, respectively.
These outputs will only output at sample rates
of up to 48 kHz. Unlike the Optical port located
on the enclosure, this Optical (ADAT) port is not
switchable to Optical S/PDIF.
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.
Enclosure Connectors
The right half of the back panel of the
192 Digital I/O features a set of non-removable
Enclosure connectors.
The connectors feature a two-channel S/PDIF
port, two additional channels of AES/EBU I/O
and another eight channels of Optical I/O.
These ports are hardwired to the 192 Digital I/O
chassis and appear on-screen in the Pro Tools
pop-up menus as AES/EBU [Encl], SPDIF [Encl],
and Optical (ADAT) [Encl]. The reference to the
enclosure [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 synchroniza-
tion ports and connectors for installing the
192 Digital I/O to your Pro Tools|HD system
and attaching other audio interfaces.
AES/EBU Digital In and Out
These are an additional pair of balanced, three-
conductor XLR connectors that accept and out-
put a stereo, 24-bit AES/EBU digital data stream
at sample rates of up to 96 kHz.
Unlike the Digital I/O card AES/EBU ports, the
enclosure AES/EBU ports do not support dual-
wire mode or provide real-time sample rate con-
version.
S/PDIF Digital In and Out
These are an additional pair of unbalanced, two-
conductor RCA jacks that accept and output a
stereo S/PDIF digital data stream. S/PDIF sup-
ports up to 24-bit audio, at sample rates up to
96 kHz. To avoid RF interference during S/PDIF
transfers, use 75-ohm coaxial cable.