Planet Of Tunes - MIDI interconnection

Free technical help for digital creators - music, video, art, photography, graphic & web design

MIDI interconnection by Matt Ottewill

MIDI interfaces
Individual MIDI devices (such as interfaces, keyboards, sound modules, drum machines etc) may be connected together to create a MIDI network, typically to allow one device to "play" another, or to allow synchronised playback of a MIDI sequence.

MIDI ports

MIDI ports

MIDI connections for a typical MIDI keyboard


MIDI connector

What is a MIDI interface?

A MIDI interface takes the form of at least one or two, often three 5-pin DIN sockets called Ports (identical physically to the those used with domestic Hi-Fi) situated on the casing (usually the rear) of a MIDI device. They will be marked In, Out, and Thru.

  • The In Port accepts MIDI messages
  • The Out Port transmits MIDI data originating from the device
  • The Thru Port passes on an exact duplicate of the data received at the In port

Where can MIDI interfaces be found?

All MIDI devices have a MIDI interface containing at least 1 In and 1 Out port. Some MIDI devices have multiple In and Out ports, such as computer MIDI interfaces.

Here are some devices that have MIDI interfaces ...

  • Soundcards
  • Drum machines
  • USB computer MIDI interfaces
  • Keyboards
  • Synthesisers
  • Samplers
  • FX units
  • Digital mixers


MIDI cables carry MIDI messages in one direction only. Therefore 2 cables are required to carry messages to and from a device.

Cables terminate with so called 5 Pin Din plugs. Cable length between devices should be restricted to a maximum of 15m to ensure data integrity. It is also advisable not to daisy-chain, via their Thru ports, more than three devices.

View our MIDI system diagram next. pdf logo