MIDI Channels
MIDI Channels allow MIDI devices to only respond to the channel on which they are set. This way they can send and receive data on one channel, while ignoring the data that is being transmitted on the other channels. MIDI allows the use 16 different channels simultaneously. Depending on the quality of the instrument, it may be able to transmit and receive over all 16 channels at once, or it may only be able to transmit and receive over one channel at a time. Most MIDI messages must contain the channel number so the devices that are receiving those messages can determine how exactly to interpret them.