Installation guide

Chapter 4: Connecting Your Studio 35
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.
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
1622 I/O S/PDIF jacks are 24-bit capable, unbal-
anced, 2-conductor, phono (RCA) jacks.
Because input channels 1–2 of the 1622 I/O are
software selectable between analog or digital
format, input to these two digital channels is
disabled when analog input is chosen in the
Hardware Setup dialog in Pro Tools.
Output is continuously active on the S/PDIF
output jack, even if the 1622 I/O input selector
is set to analog in the Hardware Setup dialog. To
avoid RF interference, use 75-ohm coaxial cable
for S/PDIF transfers and do not exceed a cable
length of 10 meters.
60-pin Interface Connector
This 60-pin connector is used to connect the
1622 I/O to a MIX or d24 card. The appropriate
interface cable is supplied with the 1622 I/O.
Power Input
This connector accepts a standard AC power ca-
ble. The 1622 I/O 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.
Making Signal Connections to
the 1622 I/O Interface
Depending on how you plan to use the
1622 I/O, the way you connect it to your studio
will vary.
Adjusting 1622 I/O Gain Levels
The 1622 I/O input levels are adjustable
through the Pro Tools software to accommodate
a variety of equipment output levels. For opti-
mum fidelity and signal-to-noise performance,
you should adjust these inputs according to the
devices that you connect to them.
After you have set up, configured, and launched
Pro Tools, refer to the instructions below for ad-
justing input gain levels for the 1622 I/O.
To adjust input level gain on the 1622 I/O:
1 Connect the instrument or device to the
1622 I/O.
2 In Pro Tools, choose Setups > Hardware.
3 Click Other Options.
4 Set the input trim slider to match the output
level of the connected instrument. (Refer to the
manufacturer’s documentation for details.) If
you do not know the output level of the device,
use the default input trim level, then fine tune
the input level gain using the procedure below.
5 Select the desired output gain level, +4 dBu or
–10 dBV, and click Done.
For best signal-to-noise performance, set the
1622 I/O input gain to +4 dBu when record-
ing devices that provide this output level.
TDM_Install.book Page 35 Saturday, January 13, 2001 9:35 PM