Connect the female end of a five-pin MIDI cable to your MIDI device, for example your outboard mixing controller.
Connect the male end of the same cable to the female MIDI input on the rear of the Alesis HD24. There are two MIDI ports on the Alesis HD24; they are located on the bottom row of sockets, almost in the center of the rear panel. The "MIDI-in" port is to the left of the "MIDI-out" port.
Turn on the Alesis HD24. The power switch is on the rear panel, on the left-hand side as you face it.
Turn on the external MIDI device. Press the light-blue "MIDI" button on the right-hand side front control panel. The LED will display the name of the MIDI device that is connected. The MIDI in application is suitable for hooking up external mixers, sequencers, time code and controllers. If you have a MIDI-enabled mixer, you can use this to send MIDI Machine Control commands to the HD24 machine. Typical commands include automation settings, time code and mix commands.
Connect the male end of a second MIDI cable to the "MIDI out" port on the rear of the Alesis HD24. The "MIDI out" port is to the immediate right of the "MIDI in" port.
Connect the female end to the "MIDI in" port on an external MIDI device.
Turn on the external device. It will automatically recognize the MIDI source, but the method by which this synchronisation is displayed varies according to the make and model of the machine. Some machines will have a flashing LED, others will have a digital LED screen that displays the name of the Alesis HD24 machine. The MIDI out configuration is suitable for routing the Alesis HD24 to a tape recorder. All recording devices have an internal timer, the MIDI connection synchronizes multiple recording devices so that they commence playback or record functions at the same time.