Setup Guide

003 Family Setup Guide62
These outputs are enabled when the Alt CR 
switch is enabled (lit).
Aux In
These are balanced, 1/4-inch TRS connectors for 
connecting alternate audio sources such as CD 
players or tape decks. The signal from these in-
puts can be routed directly to the Main Monitor 
Outputs (for monitoring) or to Inputs 7–8 (for 
direct input into Pro Tools) from the top panel 
of 003, or the front panel of 003 Rack.
Operating levels for these inputs are fixed at 
+4 dBu.
When the Aux In switch is enabled (lit), Aux In 
signal is routed to the Main Monitor Outputs. 
Audio in Pro Tools that is routed to Analog 1–2 
will not be mirrored at the Monitor Outputs.
When the Aux In to 7/8 switch is enabled (lit), 
Aux In signal is routed to Inputs 7–8 and does 
not pass directly to the Monitor Outputs.
When the Alt CR switch is enabled (lit), audio 
routed to Aux In will pass out the Alt Monitor 
Outputs.
Digital I/O
S/PDIF Digital I/O
The S/PDIF in and out ports are unbalanced 
two-conductor phono (RCA) connectors that 
utilize a full 24-bit, two-channel digital data 
stream.
The Sony/Philips Digital Interface Format 
(S/PDIF) is used in many professional and con-
sumer CD recorders and DAT recorders. For 
highest digital signal integrity, and lower jitter, 
use 75 Ohm coaxial cable for S/PDIF transfers 
and keep the cable length to a maximum of 10 
meters. 
003 and 003 Rack support consumer mode S/PDIF 
output format (IEC60958-3) at sample rates of 
44.1 kHz and 48 kHz, and professional mode 
S/PDIF output format (IEC60958-4) at sample 
rates of 88.2 kHz and 96 kHz. For information 
on which S/PDIF formats are supported by your 
S/PDIF-compatible gear, see the manufacturer’s 
documentation.
Optical I/O
These are a pair of TOSLINK-style connectors for 
ADAT Optical (8 channels of I/O) or S/PDIF Op-
tical (2 channels of I/O) devices. You can choose 
between these Optical I/O formats in the 
Pro Tools Hardware Setup dialog.
The Optical port can be set for eight channels of 
ADAT Optical I/O (supporting up to 48 kHz) or 
two channels of S/PDIF Optical I/O. 
The Optical I/O ports support 24-bit, 20-bit and 
16-bit resolutions in both modes. 
The Optical I/O ports use a standard optical 
“lightpipe” cable.
When the 003 or 003 Rack is on, its Optical Out 
port emits a red light.
Only one S/PDIF input pair can be used at a 
time. For example, if you use the Optical In 
for S/PDIF data, you cannot use the RCA in-
puts.
At 96 kHz, it is recommended that you use 
the S/PDIF (RCA) port
Digidesign recommends high-quality audio 
grade optical cable for all optical connec-
tions.










