Mackie MDR24/96 Operation Manual page 20

If the MDR is set to slave to external time
code (MTC or SMPTE time code),
engaging the Time Code Chase mode
causes the MDR24/96 transport to follow
time code coming from an external master
source. If disengaged, the MDR will go off
line and will no longer follow the external time code. This function is enabled with
the T. CODE CHASE button.
In the Time Code Chase mode, pressing the PLAY button causes the transport to
wait in an armed state for time code to start. Start, stop, wind, and locate
functions follow the time code master.
The MDR24/96 does not resolve its word clock to incoming time code, it only uses
time code to synchronize transport time. Once the MDR24/96 transport has
jumped to the time code time and started running, it runs on its internal clock,
while continuously monitoring the incoming time code. It will stay locked as long
as the time code doesn't drop out or otherwise become corrupt for longer than its
"flywheel" window of ten frames. If the time code problem is corrected within that
window, the MDR24/96 will continue to chase. If not, it will drop out of time code
chase mode and stop.
You can disengage TC Chase on the fly, however, without interrupting the MDR24/96's
operation. If you're working with really poor quality time code, for example what
might come from an inexpensive VCR, by disengaging TC Chase after the MDR24/96
has found its time code-related position, it will free-run and not sweat the unstable
time code. Synchronization won't be perfect, but this is a means of working with
problem time code.
The MDR24/96 can chase time code from either MIDI In or SMPTE In. Use Time Code
Source to select either SMPTE or MTC.
There are four standard time code frame
rates, each developed for a specific
application. In addition, two of the frame
rates have variations called drop-frame,
mostly used in broadcast applications to correct timing issues caused by the 29.97
frame rate. Use the Time Code Rate option to set the time code frame rate to one
of the following settings: 30, 30 Drop, 29.97, 29.97 Drop, 25 and 24. If you're not
involved in video or broadcast applications, 30 frames per second (fps) is your best
choice.
You can set the MMC (MIDI Machine
Control) Device ID independently for each
group of eight tracks. Most 24-track MMC
control devices share the same Device ID
for the three 8-track blocks.