Installation guide

TDM Installation Guide32
To return the 882/20 I/O to Pro Tools-based
operation:
■ Turn on your computer.
– or –
■ If your computer is on, launch Pro Tools.
The 1622 I/O Interface
This section explains the connectors and indica-
tors on the front and back panels of the
1622 I/O interface, how they are used, and of-
fers suggestions for connecting the 1622 I/O to
your studio.
1622 I/O Front Panel
The 1622 I/O has the following front panel indi-
cators, moving from left to right:
Power
This switch applies power to the 1622 I/O. The
“I” position is on. The “O” position is off.
Sync Mode
The Sync Mode LEDs indicate which sample rate
clock reference is currently used by the analog-
to-digital converters (ADCs) and the digital-to-
analog converters (DACs).
Internal This is the 1622 I/O standard setting. In
this mode, the 1622 I/O sample rate is generated
by its internal crystal oscillator (whose fre-
quency is determined by the Sample Rate setting
in the Session Setup window). Internal mode
should be active whenever the 1622 I/O is not
synchronized to an external clock source.
Digital This setting indicates that a S/PDIF word
clock signal is the source for the 1622 I/O sam-
ple rate. This is the setting to use for inputting
material from DAT machines or other S/PDIF
digital devices.
To use the 1622 I/O digital input and output as
an effects send and return to a digital effects de-
vice, set the 1622 I/O to Internal mode. Set the
digital effects device to accept an external digital
clock (from the 1622 I/O) so it synchronizes
with Pro Tools.
In expanded Pro Tools systems, the Super Clock
output of the master audio interface locks all
other interfaces together with sample accuracy,
keeping all signals phase-synchronous.
Front panel of the Digidesign 1622 I/O
Power
Sync
Mode
Ch 1–2 Input
Input Meters
Channel 15–16
Direct Inputs
Sample
Rate
Output Meters
Because some digital audio devices do not
output proper clock when they are not play-
ing back, leaving the 1622 I/O in Digital
mode may cause Pro Tools audio playback
quality to suffer, or to play back at the
wrong pitch. If you are using digital I/O, re-
set the Sync Mode from Digital to Internal
after inputting material.
TDM_Install.book Page 32 Saturday, January 13, 2001 9:35 PM