1248 Rear Panel - MOTU 1248 User Manual

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1. The 1248 is equipped with an auto-switching interna-
tional power supply.
2. BNC word clock jacks. Use them for a variety of applica-
tions, such as digital transfers with devices that cannot
slave to the clock supplied by their digital I/O connection
with the 1248.
3. These ADAT optical "lightpipe" jacks provide 16 channels
of 24-bit ADAT optical digital I/O at 1x sample rates (44.1
or 48 kHz) and 8 channels at 2x sample rates (88.2 or 96
kHz). They are disabled at higher sample rates. The IN
and OUT ports on the right provide channels 1-8 (or 1-4
at 2x sample rates), and the left-hand ports provide
channels 9-16 (or 5-8 at 2x sample rates).
4. These jacks provide stereo, 24-bit S/PDIF digital input
and output at all supported sample rates (up to 96 kHz).
The input provides sample rate conversion, as explained
in "S/PDIF with sample rate conversion" on page 53.

1248 Rear Panel

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5. The MONITOR OUT pair provides auxiliary stereo analog
output for secondary studio monitors, or any other
desired destination. These connectors are balanced (TRS)
quarter-inch connectors that can also accept an unbal-
anced plug (with the ring disconnected). Control volume
from the MOTU Pro Audio Control web app or from the
front panel volume control.
6. The MAIN OUT pair provides stereo analog output for
primary (powered) studio monitors or PA speakers, or
any other desired destination. These connectors are
balanced (TRS) quarter-inch connectors that can also
accept an unbalanced plug (with the ring disconnected).
Control volume from the web app or from the front panel
volume control.
7. The 1248's eight analog outputs are balanced (TRS)
quarter-inch connectors that can also accept an unbal-
anced plug (with the ring disconnected). The output trim
can be adjusted from the Output Setting section of the
Device Tab in the MOTU Pro Audio Control web app
software.
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8. These eight analog inputs are balanced (TRS) quarter-
inch connectors that can also accept an unbalanced plug.
Use with line level signals up to +24 dBu, including
synthesizers, drum machines, effects processors, etc.
These inputs are also equipped with the 1248' s Precision
Digital Trim™ feature: digitally controlled analog trims
that let you adjust input level in 1 dB increments from
the included MOTU Pro Audio Control web app software.
9. Connect up to four microphones here. Each input
provides individual preamp gain (63 dB), switchable 48V
phantom power, and an optional -20 dB pad.
10. Connect the 1248 to the computer here via either
Thunderbolt or USB 2.0, using a standard Thunderbolt or
USB cable. For details, see "Setup for multiple Thunder-
bolt and USB interfaces" on page 46.
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11. This AVB Ethernet port provides industry standard IEEE
802.1 network connectivity to other network devices.
Examples include:
■ Another 1248 or any other MOTU AVB-equipped audio
interface, such as the 1248, 8M, 16A, 24Ai, 24Ao, 112D,
Monitor 8, etc.
A standard Ethernet hub or Wi-Fi router (for internet
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connection and communication with the MOTU Pro
Audio Control web app software).
A standard AVB Ethernet switch for high-speed, low-
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latency, high-capacity audio connectivity to an AVB
audio network.
A recent-generation Mac (any Mac with a Thunderbolt
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port) running OS X El Capitan (10.11) or later. This
allows you to operate the 1248 as an audio interface
over Ethernet.