8x2 Video Matrix Switch
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6. Addendum
6.1 Switching with or through a Serial Device
The VSM-802B has two serial ports, one for each of the keypads. One
or both of these ports can be used to control the switch from an
external serial device.
The serial connectors are DB9-F. The following list shows pins used:
Pin 1 (reserved) = Used by keypad (must be left open)
Pin 2 (output) = TX from switch
Pin 3 (input) = RX to switch
Pin 4 (input) = DSR to switch (must be hi for switch to transmit)
Pin 5 (Gnd) = Ground
Pin 6 (output) = DTR from switch (hi indicates ready to receive)
Pin 7 (n/u) = Not Used
Pin 8 (n/u) = Not Used
Pin 9 (reserved) = Used by keypad (must be left open)
Configure port for 9600 Baud, 8 bits, No Parity, 1 Stop bit
Serial Commands:
All commands are made up of ASCII characters followed by carriage
return. x and y are input and output channel numbers respectively.
OyIx
Connects y output to x input. If x is 0, then y output is
blanked. The switch will send out an identical string (i.e. OyIx) when
the action is completed
Oy?
Returns status of y output in the form of OyIx
You can still have a keypad connected to one of the serial ports and
control the switch simultaneously from an external serial device. If the
output associated with the keypad that is connected is changed via the
external serial device, then the keypad LEDs will reflect the new
selection.
