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If you use both a keypad (see Section 4.2) and a serial device to control the
Switch, keep in mind that the keypad can switch its own output independently of
the serial device, and the serial device can switch both outputs independently of the
keypad. If the serial device switches the keypad's output, the state of the keypad's
LEDs will change to reflect the switch.
4.4 Blanking the Video Output and Performing a Keypad Self-Test
4.4.1 W
K
ITH THE
EYPADS
Pressing both the 9 and 10 buttons simultaneously on one of the Switch's keypads
will blank the video output controlled by that keypad (the monitor will go dark). It
will also cause that keypad to go into self-test mode and light all of its LEDs.
If you see that any of a keypad's LEDs don't light while it's in self-test mode,
consider contacting Black Box to arrange for the keypad to be repaired or
returned. (A dark LED probably just means that the LED is defective, but there's a
slim chance that something more serious might be wrong.)
To exit test mode and restore video output, press any of the buttons 1 through 8
to select the corresponding channel.
4.4.2 W
S
ITH A
ERIAL
To blank either output using a serial-control device, send one of the following
command strings to either of the Switch's KEYPAD ports:
• Single-head video: Send "O1I0 [Enter]" (uppercase letter O, number one,
uppercase letter I, number zero, carriage return) to blank output #1.
Send "O2I0 [Enter]" (uppercase letter O, number two, uppercase letter I,
number zero, carriage return) to blank output #2.
• Dual-head video: Send "I0 [Enter]" (uppercase letter I, number zero, carriage
return) to blank both outputs.
After the Switch receives the command and blanks the designated monitor, it
will send a copy of the command string, including the carriage return, out of both
KEYPAD ports. (Attached serial-control devices must be able to either ignore such
strings or react appropriately to them. Any attached keypad that receives such a
string will go into self-test mode and light all of its LEDs if the string affects its
output; it will ignore the string otherwise.)
Refer to Section 4.4.1 if you see that any of a keypad's LEDs don't light while it's
in self-test mode. To exit test mode and restore video output, send a switching
command (see Section 4.3) to select channel 1 through 8.
D
EVICE
CHAPTER 4: Operation
17
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