| Microsoft DirectX 8.1 (Visual Basic) |
System messages are not exclusive to any channel. There are three kinds, as shown in the following table.
| Message type | Purpose |
| System common | Miscellaneous commands and data. |
| System exclusive | Equipment-specific commands and data. |
| System real-time | Synchronization of clock-based MIDI equipment. |
Unlike other MIDI messages, system exclusive messages can contain any number of data bytes. After transmitting the data, the sequencer sends a system common message called an EOX, which signals the end of the system exclusive message.
DirectX for Visual Basic does not give applications direct access to system exclusive messages.