Roland Audio Canvas UA-100 User Manual page 13

MIDI Interface Block
If your computer and the UA-100 are connected via a USB cable, the UA-100 will have
two MIDI ports for controlling external MIDI devices (MIDI IN 1, 2 and MIDI OUT 1,
2), and one MIDI port for controlling the UA-100 (UA-100 MIDI Control IN, OUT).
fig.02-02ae
If your computer and the UA-100 are not connected via a USB cable, MIDI messages
from the MIDI IN 1 connector will be routed to internal control of the UA-100, allowing
an external MIDI device to control the UA-100.
fig.02-02be
The Signal Flow of the UA-100
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