6-7
If all of the above conditions exist, then the DA20 will automatically assert Format 10 thus
eliminating the need to separately cue digital films or trailers. The DA20 will continue to
assert Format 10 commands after any film format assertion in order to keep the CP200 in
Format 10 as long as valid digital data is available.
After the DA20 has asserted Format 10, if valid digital data is no longer available, then the
DA20 will revert to analog. Though the CP200 will remain in Format 10, the yellow
‘Analog” LED will light and the audio signal path will switch to the analog SR track. At
this point, an automation system or operator can assert any format. The DA20 will not re-
assert Format 10 until valid digital data is again available.
To disable the automatic selection of Format 10 by the DA20, two methods are provided
in CP200 installations.
First, the CP Type switch can be set to position 7. This disables the ability of the DA20 to
assert any format commands except those associated with analog reversions when in
Format 10.
Second, the ‘GO’ button on the CP200 can be pressed and held for at least 4 seconds.
After 4 seconds has elapsed, the green ‘Digital” LED on the DA20 will go off and the
‘Analog’ LED will flash. At this point, the CP200 will be playing the analog SR track and
any format can be selected without the DA20 forcing the CP200 back into Format 10. If
Format 10 is again selected, the DA20 will remain in analog reversion mode thus forcing
the CP200 to play the analog SR track. Auto-digital mode can not be re-enabled unless
the DA20 is turned off and then on again or the CP Type switch is rotated out of and back
into position 3. This will cause the DA20 to re-scan the CP200 format selectors and look
for Format 10 again and therefore should not be done while film is playing.
Power Failure:
If for any reason the DA20 loses power or resets while in format 10, it will send a format
05 command to the cinema processor. This prevents loss of sound due to DA20 failures or
power loss. This will happen regardless of the position of the cinema processor type
switch.
6.5
Auxiliary Data Channel
An auxiliary data channel is available on the DA20 rear panel (J9) and requires an RS-232
compatible device. Refer Section 5 for technical data on this feature.
6.6
Two Projector Changeover Operation
The DA20 “changes over” between Cat. No.700 Digital Soundheads by switching
between digital data signals at a time in advance of the actual picture changeover. The
data on the film is read by the Digital Soundhead ahead of the picture gate by typically
1-1/2 seconds. A delay circuit in the DA20, set during installation, compensates for this
“early” reading of data. In order for a changeover to be seamless, the switchover to the
incoming digital data must happen “early” as well. The Motor Start signal (a contact
