Roland UM-3EX Owner's Manual page 11

■ ON/OFF Settings of the THRU Switches
You can use the THRU switches to select the transmission destinations for MIDI messages
from the devices (MIDI keyboard, digital piano, etc.) connected to the MIDI IN connectors.
There is no need to change any cable connections.
THRU Switch:
OFF
THRU Switch:
ON
fig.thru-e.eps_60
* Don't change the setting of a THRU switch while playback is in progress. Doing so will cause MIDI
errors.
6
USB Indicator
This will light when you've connected the UM-3EX to your computer and your computer has
detected the UM-3EX.
In order for your computer to detect the UM-3EX, you must install the driver and make settings.
(➔"Getting Connected and Installing Drivers (Windows)" (p. 14), "Getting Connected and
Installing Drivers (Macintosh)" (p. 24))
MIDI messages arriving via the corresponding MIDI IN connector are
sent to your computer (sequencer software). Normally, you should
use this setting.
MIDI messages arriving via the corresponding MIDI IN connector on
the UM-3EX are output from the corresponding MIDI OUT/THRU
connector of the UM-3EX. Turn this on if you're not using sequencer
software.
MIDI Message Flow (THRU OFF)
MIDI Message Flow (THRU ON)
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