Taken from
the Roland SCC-1 Owner's Manual
, page 23-24.
MIDI stands for Musical Instrumental Digital Interface, a world-wide
standard for exchanging performance data among computers and
electronic musical instruments. An instrument conforming to the MIDI
standard, no matter what kind or who made it, can send and receive
performance data. This MIDI data is not music itself, but rather a
way of handling a variety of digitally-encoded messages telling the
instrument what to do.
Midi data exchange is not that difficult to understand.
MIDI Connections
MIDI data exchange is achieved through three
connectors. MIDI cables are used to connect
these connectors in whatever arrangement you
need for a particular job.
MIDI IN
: MIDI data is received from other
devices.
MIDI OUT
: Data is sent to other devices.
MIDI THRU
: The data sent to MIDI IN is sent back
out, unchanged.
MIDI Channels
Data for a number of different MIDI devices can
be sent over the same MIDI cable. This is the
result of the MIDI Channel concept.
A MIDI Channel is a lot like a TV Channel. As you
switch channels, you see completely different
programs; but this information is only received
when the channel on your TV is set to the same
channel that the TV station is broadcasting on.
MIDI has channels numbered 1-16, and MIDI data on
any one channel is sent to all instruments set to
receive on that same channel. For example, a MIDI
cable connects a MIDI keyboard's MIDI OUT
connector to sound module A's MIDI IN connector.
Another MIDI cable connects sound module A's MIDI
THRU connector to sound module B's MIDI IN. The
keyboard is set to trasmit at channel 1, sound
module A is set to receive at channel 2, and
sound module B is to receive from channel 1.
Because the keyboard is transmitting at channel
1, and only sound module B is receiving at
channel 1, only sound module B will play.
