Avid HD OMNI Preamp, I/O, and Monitoring Pro Tools HD Series Interface - Manual (Page 23)

Chapter 3: Connecting HD OMNI 19
Connecting Loop Sync
If you are using two (or more) Pro Tools audio interfaces or a SYNC peripheral, Loop Sync must be
connected to maintain proper clock among the devices. For an example of connecting multiple
Pro Tools|HD audio interfaces, see Figure 2 below.
To make Loop Sync connections:
1 Connect (daisy-chain) the Loop Sync Out of each interface to the Loop Sync In of the next interface
with the BNC cables included with your audio interface.
2 Connect the Loop Sync Out of the last interface to the Loop Sync In of the primary interface or
SYNC peripheral.
Figure 2. HD OMNI connected to the DigiLink Port on a Pro Tools|HD Accel Core card and HD I/O connected to the
DigiLink Mini Expansion port on HD OMNI. A second HD I/O is connected to the DigiLink Port on a Pro Tools|HD Accel
card with a third HD I/O connected to the Expansion port on the second HD I/O. Loop Sync (BNC) cables connect the
HD OMNI and all three HD I/Os.
12-foot DigiLink Mini Pro Tools|HD Accel Core card
to DigiLink cable
Pro Tools|HD Accel card
Loop Sync cables
18-inch DigiLink
Mini cable