Future Retro Zillion Owner Manual - Manual (Page 28)

SYNC
In the Sync mode you can set the Zillion to play by its internal clock, or
sync to an external MIDI clock.
The top line of the display will indicate if sync is set to internal or
external.
The bottom line of the display will indicate if just MIDI notes, or MIDI
notes and MIDI clock will be transmitted from the Zillion’s MIDI output.
Use the +/- keys to choose one of the four possibilities.
When the Zillion is set to external sync, make sure your master MIDI
output is connected to the MIDI IN of the Zillion. Starting and stopping
playback of the external device acting as the master clock will then
remotely control the start/stop playback of the Zillion as well as the
tempo.