Hall Research HR-3P - Manual (Page 6)

Projector Controller w/ Built-n VGA Splitter
6
Selecting the Scan
Priority
The scan priority exists to give one
video input priority over the other two.
You may also choose to give none of the
video inputs priority. The way the HR-3P
selects a video input is by cycling
through each video input. It will cycle in
the order of VGA, S-Video, Composite,
and then it will start again with VGA and
continue to scan. As soon as a signal is
detected on any of the inputs, that
video input is selected. After an input is
selected, no other input will be selected
until that original video input is
unplugged or turned off or the video
input with priority is turned on. If for
example S-Video had priority and no
video inputs were selected then the HR-3P would just cycle through each input looking for
a signal. If the first signal it finds is Composite then it would select composite and send the
Composite Input Active string out the serial port. If it then found the VGA signal to be
active, it would not select the VGA input since the VGA input does not have priority. If the
Composite input were to be unplugged then the HR-3P would select the next active signal
in order of scanning. In this case it would select VGA since VGA is the next signal in the
scanning cycle that is active. If S-Video were to become active later while VGA was
selected, S-Video would then become selected over VGA since S-Video has priority. Only 1
video input may have priority at any given time. By default, scan priority is given to none.
Selecting a delay for the No Input Active string
By default, the No Input Active string is sent out through
the serial port as soon as there are no active inputs to
select from, i.e.: there is no video signal at any of the three
input connectors. If you want to delay the No Input Active
string then you simply fill in the fields for the amount of
wait you want to add. If, for example, you wanted to send
out the No Input Active string 1 hour, 15 minutes and 30
seconds after the HR-3P had detected no active signals
then you would enter a 1, 15 and 30 in the respective
fields. Typical commands to send in this situation might be to have the projector enter
standby mode or to turn it off.