Korg prologue Owner's Manual page 69

Slaving the prologue clock to an external MIDI device
Connect the MIDI IN connector of the prologue to the MIDI OUT connector on your
external MIDI device.
In the GLOBAL EDIT mode, set the Clock Source of the prologue to "Auto (MIDI)",
and configure the external MIDI device to transmit MIDI clock data.
The prologue will automatically act as the slave whenever a MIDI timing clock is
received, and will be driven by the tempo of the external MIDI device (sequencers,
rhythm machines, and so on).
Even if you set the Clock Source to "Auto (USB)" or "Auto (MIDI)", the
TIP
prologue will operate in "Internal" MIDI clock mode, unless a clock is re-
ceived from an external device.
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