Avid Technology Digidesign USD, User Manual, Page: 25 / 96

Chapter 3: USD Hardware and Software Overview 21
5. Mac Serial Port
A bidirectional (in/out) port designed for
use exclusively with the DigiSerial Port
found on all Pro Tools MIX and d24 cards,
or to a modem/printer port on a compati-
ble Macintosh host computer.
Connector: Female mini DIN-8 (8-pin)
6. Video In
Receives a signal from an NTSC/PAL video
source for clock or VITC positional refer-
ence input, or for generating a window
burn. This connector is internally termi-
nated at 75 ohms.
Connector: Female BNC
7. Video Out
If the Positional Reference is set to Gener-
ate and the Clock Reference is set to one of
the two video inputs, this will output a
copy of the video signal appearing at the
Video Reference input. Under all other
combinations of Positional and Clock Ref-
erence settings, this will output a copy of
the video signal appearing at the Video In
input.
In either case, this output might addition-
ally carry VITC and/or Window Burn infor-
mation if those features are enabled.
Connector: Female BNC
8. MTC Out
Outputs MIDI Time Code (MTC), only. No
other MIDI data appears at this output.
MTC output can be regenerated while the
USD is locked to any supported positional
reference and clock reference, or internally
generated in Generate mode, in which case
MTC output follows generator run/stop.
Intended to supply MTC from the USD to
external sequencers or other MIDI devices.
Connector: Female standard, DIN 5-pin
9. LTC In
Receives a Linear Time Code (LTC) source,
balanced or unbalanced analog, for clock
and positional reference. This port is often
used to receive LTC from an audio track on
an external deck or the address track of a
VTR.
Connector: Female XLR-style 3-pin
(Pin 2 “+” or “hot,” Pin 3 “–” or “cold”)
10. LTC Out
Outputs linear time code, in balanced or
unbalanced analog audio format.
Connector: Male XLR-style 3-pin
(Pin 2 “+” or “hot,” Pin 3 “–” or “cold”)
When the LTC Out port is connected in
unbalanced mode, Pin 3 must be
grounded. See Appendix C: Wiring Diagrams
Pin Assignments for wiring details.
11. AES/EBU In
Receives an AES/EBU digital audio signal,
for clock reference purposes only. The USD
utilizes only the signal's clock information,
not the audio information. If digital audio
information is present at this input, it will
be ignored and not passed through to the
AES/EBU digital output connector.
Connector: Female XLR-style 3-pin
(Pin 2 “+” or “hot,” Pin 3 “–” or “cold”)