Sony HDCU3100 Operating Instructions Manual page 8

For details on how to select the signal, contact a Sony service
or sales representative.
q SDI I/O (3G/HD-SDI input/output) 1/2/3/4 connectors
(BNC-type)
These can be used as return video inputs, HD prompter
inputs, camera video signal outputs, and HD-TRUNK outputs.
Set them in NETWORK TRUNK on the <TRUNK/
PROMPTER> page of the MAINTENANCE menu according to
the application.
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