Specifications

Chapter 3: Installation Overview 25
You will be able to select the sample rate each
time you create a new session.
SYNC MODE Indicators
The SYNC MODE LEDs indicate the current
clock source.
INT (Internal) This is the 192 I/O standard clock
setting. In this mode, the 192 I/O sample clock
is generated by its internal crystal oscillator, as
determined by the session Sample Rate.
DIG (Digital) This setting indicates that an exter-
nal AES/EBU, TDIF, Optical (ADAT), or S/PDIF
device is providing system clock. If you wish to
use an AES/EBU or S/PDIF device as Clock
Source, you will have to select the correspond-
ing Digital Input format. If no valid clock source
is detected, 192 I/O will switch to INT, the DIG
LED will flash, and an error message will appear
on-screen in Pro Tools.
To record from an AES/EBU source, select
AES/EBU for Digital Format and make sure it is
not selected in Clock Source.
To connect digitally with other digital devices
that are functioning as more than an input de-
vice (such as when sending and returning sig-
nals to and from an external digital signal pro-
cessing device) be sure to set the external digital
device to external clock. This will allow the ex-
ternal digital device to clock off the digital out-
put port you are using on the 192 I/O.
The 192 I/O can function in this way while in
Internal clock mode, and can use a third device
as Clock Source.
If at least two channels are not assigned from
the selected digital port in the Main page of the
Hardware Setup dialog, or if no valid clock
source is detected at this port, 192 I/O will
switch to INT and the DIG LED will flash.
LOOP (Loop Master) This LOOP LED indicates
that the 192 I/O is slaving to another HD I/O
through Loop Sync. You do not set LOOP mode
anywhere in the software. This is done automat-
ically when you choose another I/O as LOOP
MASTER by selecting its Clock Source.
Loop Sync is used when multiple HD I/O's are
installed in a system. Loop Sync is a separate
word clock signal used to keep all HD I/Os syn-
chronized with each another. Only one periph-
eral at a time in the entire system can serve as
LOOP MASTER, and by default this will be the
HD I/O connected to the HD Core card.
You can select any connected HD I/O to be the
Loop Master by choosing a clock source on that
particular HD I/O. Once you set this, all other
peripherals in the chain will automatically be
set for Loop Slave and light the LOOP LED.
Front panel synchronization mode setting LEDs
You will not be able to use the Optical
(ADAT) [Encl] port as an eight-channel syn-
chronization source if the radio button for
Optical S/PDIF is selected. Likewise, you
must first select the radio button for Optical
S/PDIF in the Digital Format section if you
want to use the Optical (ADAT) port to syn-
chronize to receive Optical S/PDIF (also
known as TOS-Link, it supports sampling
rates up to 96 kHz).