Apple Logic Express 9 - Manual (Page 1173)

Logic Express ignores these messages when incoming external MTC (MIDI time code)
commands are detected.
Logic Express also obeys Full Frame Messages, and sets the playhead to a new location,
without starting playback. Once again, incoming MTC data has higher priority, if
conflicting information is received.
Some synchronizers send Full Frame Messages (instead of MTC) to locate the slave
device (Logic Express in this case) to a new position, without implicitly starting playback.
This is useful when in Slow Shuttle or Single Frame Advance mode with video machines,
because the slave device is perfectly located, without being in playback mode.
Other MIDI Settings
• MIDI Sync Preferences button: The MIDI Sync Preferences button opens the Sync pane
of the MIDI preferences. (See MIDI Preferences in Logic Express .)
Unitor Synchronization Settings
The Unitor pane of the Synchronization project settings is used to set the major
synchronization parameters for the Unitor8 MIDI interface.
1173 Chapter 42 Project Settings in Logic Express