JLCooper MCS3 SP USB for OSX - Manual (Page 19)

When Custom MIDI is chosen, more controls will become visible for editing the custom
messages.
The MIDI Message Type popup lets you choose any of the basic MIDI messages
except for system exclusive and MIDI Time Code.
The first group of messages in the popup include a MIDI channel. If you choose one of
these message types, a channel editor appears. You can either type or use the up and
down arrows to set the channel. This editor accepts values from 1 through 16.
MCS3 SP USB Software
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