Midi Message Basics; Channel Messages; A Voice Messages - Alesis GT Reference Manual

key, the MIDI Out transmits another piece of data that says "middle C has
been released."
If the keyboard responds to the dynamics of your playing, the note data
will include dynamics information too. Moving the modulation wheels
and pedals attached to many synthesizers will also generate data
associated with the wheel or pedal being used.
The MIDI In jack receives data from another MIDI device. In addition to
the type of performance data described above, rhythmically-oriented
MIDI devices (e.g., drum machines) can often transmit and/or receive
additional MIDI timing messages that keep other rhythmically-oriented
units in a system synchronized with each other.
An optional MIDI Thru jack provides a duplicate of the signal at the
MIDI In jack. This is handy if you want to route MIDI data appearing at
one device to another device as well. Some devices, like the Quadraverb
GT, switch their MIDI Out between the Out and Thru functions.
Example: Suppose a keyboardÕs MIDI Out feeds the QuadraVerb's MIDI
In. If the QuadraVerbÕs MIDI Out is set to function as a Thru jack, you
could patch it to the input of an MMT-8 sequencer. Thus, the keyboard
would control the QuadraVerb and be able to record data into the
sequencer.

8.3 MIDI MESSAGE BASICS

The are two main types of MIDI messages. Channel messages, which are
channel-specific, consist of Voice and Mode messages. System messages,
which do not have a channel number and are received by all units in a
system, include Common, Real Time, and Exclusive messages.

8.4 CHANNEL MESSAGES

8.4A Voice Messages

A synthesizer's voice is the most basic unit of sound generation. Usually,
each voice plays one note at a time, so the number of notes you can play
at one time will be limited by the available number of voices. MIDI
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