| MODM_CLOSE | Closes and deallocates a MIDI output device. |
| MODM_DATA | Sends a MIDI event to the driver for output. This message is used for all MIDI events, except system-exclusive events. |
| MODM_GETDEVCAPS | Requests the capabilities of a MIDI output device. |
| MODM_GETNUMDEVS | Requests the number of MIDI output devices a driver supports. |
| MODM_LONGDATA | Sends a MIDI data block to the driver for output. The data block can contain one or more MIDI events, including system-exclusive events. |
| MODM_OPEN | Opens and allocates a MIDI output device. |
| MODM_RESET | Stops playback and returns all data blocks to the client application. |