Installation guide

Chapter 4: Connecting Your Studio 23
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
888/24 I/O S/PDIF in/out jacks are unbalanced
2-conductor phono (RCA) jacks which utilize a
full 24-bit digital data stream. To avoid RF inter-
ference, use 75-ohm coaxial cable for S/PDIF
transfers and keep the cable length to a maxi-
mum of 10 meters.
Because input channels 1–2 of the 888/24 I/O
are software selectable between analog or digital
format, input to these two digital channels is
disabled when analog input is chosen or when
AES/EBU digital format is chosen in the
Pro Tools Session Setup window. Output is con-
tinuously active on both the AES/EBU and
S/PDIF output jacks, regardless of which digital
input format is selected for channels 1–2. To
avoid RF interference, use 75-ohm coaxial cable
for S/PDIF transfers and do not exceed a cable
length of 10 meters.
Slave Clock In/Out
The Slave Clock Out jack is a standard BNC type
connector that outputs a 256 times sample rate
Super Clock signal for slaving and synchroniz-
ing multiple Digidesign interfaces and synchro-
nization peripherals together.
When the 888/24 I/O Sync Mode is set to Inter-
nal, connecting a valid Slave Clock Out signal to
this port will cause the 888/24 I/O to automati-
cally switch to Slave mode. When the
888/24 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 888/24 I/O 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.
Power Input
This connector accepts a standard AC power ca-
ble. The interface automatically selects power
(100 V to 240 V) and will automatically work
with a standard modular cable to connect to AC
power receptacles in any country.
Changing Operating Levels of
Individual 888/24 I/O
Channels
The 888/24 I/O is factory set to +4 dBu operat-
ing levels for input and output. However, the
888/24 I/O allows you to individually switch
any of its analog inputs or outputs to either a
+4 dBu or –10 dBV operating level by moving
internal jumpers on its circuit board.
Input and output level switches inside the 888/24 I/O
output level
adjustment switches
+4 dBu or -10 dBV
input level
adjustment switches
+4 dBu or -10 dBV
TDM_Install.book Page 23 Saturday, January 13, 2001 9:35 PM