One of the MIDI System messages (another is System Exclusive). System real time messages are a set of messages that serve as uniform timing information for the synchronization of MIDI equipment. They are sometimes just referred to as Real Time Messages. Because of the timing-critical nature, a system real-time byte can be inserted into the middle of any multi-byte MIDI message. System real-time messages include MIDI clock, start, stop, continue, active sensing, and system reset.