Roland EM-303 - MIDI Connectivity and Usage; What is MIDI?, Connectors, Channels, and External Devices

What's MIDI?
SECTION 4
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Aastech
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MIDI stands for Musical Instrument Digital Interface, an industry-wide standard for
exchanging data between digital musical instruments. A MIDI-compatible instru-
ment can ‘read’ and ‘understand’ tone switching messages or performance data sent
from another MIDI instrument, even if they are completely different models or made
by different manufacturers. In the MIDI standard, data describing which keys are
played, for how long, at what volume, and so on, is handled as MIDI “messages.”
About MIDI Connecicrs
MIDI messages are transmitted or received via three MID! connectors. MIDI cables
are used to connect these connectors, depending on how they are to be used.
i — LF 2 bi xc
go FAQ
THRU OUT IN
MIDI
MIDI IN: Messages from external MIDI devices are received here.
MIDI OUT: MIDI messages from the EM-305/303 are sent to external MIDI
devices from here.
MIDI THRU: This port transmits an exact copy of all messages received via the
MIDI IN port.
* The EM-305/303 doesn’t have a MIDI THRU connector.
MIDI Channels
Rather than have one cable for each MIDI device, MIDI lets you use a single cable to
transmit messages to many MIDI devices at once. Using this arrangement, each
device gets only those messages intended specifically for it. This is where the idea of
‘MIDI channels’ comes in.
You can think of MIDI channels as being similar to television channels. When you
switch TV channels, you can see programs from a variety of different television sta-
tions, but you must be receiving on the same channel as the TV station is sending in
order to see the program.
Television signals of many broadcast stations pass through the cable trom the antenna.
Broadcast station A
Broadcast
station
B
Only
the
program
of
the
selected
channel will be seen.
Broadcast station C
\
MIDI has channels too, numbered from 1 to 16, and only when the transmitting
channel is the same as the receiving channel is the MIDI data transmitted. For
instance, in the setup on the next page, only Sound Module B will sound when you
play the keyboard, because it is receiving on the same channel that the keyboard is
transmitting (channel 1).
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