The MIDI protocol is made up of messages. A message consists of a string
(ie, series) of 8-bit bytes. These messages encode commands such;
AfterTouch (ie, key pressure)
Program (patch) change
The figure on the right depicts a 3 byte MIDI NOTE ON or NOTE OFF message.
These MIDI commands encode;
which of 16 channels the command is to be effective for,
which of 128 possible notes is specified (over 10 octaves);
the velocity or "force" by which this command was activated (assuming a key caused the note).
A MIDI NOTE ON message with a Velocity value of zero performs the same as a NOTE OFF command for the note value specified. This conforms to standard MIDI "RUNNING STATUS" note assignments. The MDD is programmed to respond to MIDI messages upon a user specified channel (Ch. 1 default).