Installation guide

Chapter 4: Connecting Your Studio 29
Because input channels 1–2 of the 882/20 I/O
are software selectable between analog or S/PDIF
digital format, input to these two analog chan-
nels is disabled when S/PDIF digital input for-
mat is chosen in the Pro Tools Hardware Setup
dialog.
The 882/20 I/O analog inputs are factory cali-
brated at a –14 dB nominal level, referenced to a
full code signal. This means that at the nominal
reference input level (either +4 dBu or –10 dBV),
you have 14 dB of headroom before clipping.
Analog Audio Outputs
These are balanced, 1/4-inch TRS jacks for ana-
log audio output connections. The 882/20 I/O
analog outputs feature 20-bit digital-to-analog
converters.
All eight output channels are continuously ac-
tive. Output operating levels are switchable be-
tween +4 dBu and –10 dBV operation. Unbal-
anced connections are supported through the
use of standard 1/4-inch TRS mono phone
plugs.
The 882/20 I/O analog outputs are factory cali-
brated at a –14 dB nominal level, referenced to a
full code signal. This means that at the nominal
reference output level (either +4 dBu or
–10 dBV), you have 14 dB of headroom before
clipping.
Slave Clock In/Out
The Slave Clock Out jack is a standard BNC type
connector that outputs a 256x audio sample rate
master Super Clock signal for slaving and syn-
chronizing multiple Digidesign interfaces and
synchronization peripherals together.
The Slave Clock In jack is a standard BNC type
connector designed to receive a Slave Clock Out
signal from another Digidesign interface, a Uni-
versal Slave Driver
™
, Video Slave Driver
™
, or
SMPTE Slave Driver
™
for synchronizing multiple
Digidesign interfaces and synchronization pe-
ripherals together.
When the 882/20 I/O Sync Mode is set to Inter-
nal, connecting a valid Slave Clock Out signal to
this port will cause the 882/20 I/O to automati-
cally switch to Slave mode. When the
882/20 I/O is the master interface or the first in-
terface in a chain, Digital mode overrides the
Slave Clock input, and an incoming Slave Clock
Out signal will not switch the 882/20 to Slave
mode.
Because crucial timing data is passed over these
ports, you should use high-quality, 75-ohm RG-
59 cables for making connections, and keep to-
tal cable length to less than 3 meters between in-
terfaces.
S/PDIF Digital Input/Output
The Sony Philips Digital Interface Format
(S/PDIF) is used in many professional and con-
sumer CD players and DAT recorders. The
882/20 I/O S/PDIF jacks are unbalanced, 2-con-
ductor, phono (RCA) jacks. Because input chan-
nels 1–2 of the 882/20 I/O are software select-
able between analog or digital format, input to
these two digital channels is disabled when an-
alog input is chosen in the Hardware Setup dia-
log in Pro Tools. Output is continuously active
on the S/PDIF output jack, even if the
882/20 I/O input selector is set to Analog in the
Hardware Setup dialog. To avoid RF interfer-
ence, use 75-ohm coaxial cable for S/PDIF trans-
fers and do not exceed a cable length of 10
meters.
TDM_Install.book Page 29 Saturday, January 13, 2001 9:35 PM