Channel Messages; System Messages; Midi Terminals - Yamaha PortaTone PSR-225 Owner's Manual

MIDI FUNCTIONS
MIDI is an acronym that stands for Musical Instrument Digital Interface, which allows electronic
musical instruments to communicate with each other, by sending and receiving compatible Note,
Control Change, Program Change and various other types of MIDI data, or messages.
The PSR-225 can control a MIDI device by transmitting note related data and various types of control-
ler data. The PSR-225 can be controlled by the incoming MIDI messages which automatically deter-
mine tone generator mode, select MIDI channels, voices and effects, change parameter values and of
course play the voices specified for the various parts.
MIDI messages can be divided into two groups: Channel messages and System messages. Below is an
explanation of the various types of MIDI messages which the PSR-225 can receive/transmit.

Channel Messages

The PSR-225 is an electronic instrument that can handle 16 channels. This is usually expressed as "it
can play 16 instruments at the same time." Channel messages transmit information such as Note ON/
OFF, Program Change, for each of the 16 channels.
Message Name
Note ON/OFF
Program Change
Control Change

System Messages

This is data that is used in common by the entire MIDI system. System messages include messages like
Exclusive Messages that transmit data unique to each instrument manufacturer and Realtime Mes-
sages that control the MIDI device.
Message Name
Exclusive Message
Realtime Messages
The messages transmitted/received by the PSR-225 are shown in the MIDI Implementation Chart on
page 114.

MIDI Terminals

In order to exchange MIDI data between multiple devices,
each device must be connected by a cable.
The MIDI terminals of the PSR-225 are located on the rear
panel.
MIDI IN ........... Receives MIDI data from another MIDI device.
MIDI OUT ....... Transmits the PSR-225's keyboard information as
94
MIDI data to another MIDI device.
PSR-225 Operation/Panel Setting
Messages which are generated when the keyboard is played.
Each message includes a specific note number which corre-
sponds to the key which is pressed, plus a velocity value based
on how hard the key is stuck.
Voice number (along with corresponding bank select MSB/LSB
settings, if necessary).
Messages that are used to change some aspect of the sound
(modulation, volume, pan, etc.).
PSR-225 Operation/Panel Setting
Reverb/chorus/DSP settings, etc.
Clock setting
Start/stop operation
IN MIDI OUT
• Special MIDI cables (sold sepa-
rately) must be used for connecting
to MIDI devices. They can be
bought at music stores, etc.
• Never use MIDI cables longer than
about 15 meters. Cables longer
than this can pick up noise which
can cause data errors.