VP-23DS Communication Protocol
23
NOTE 2
These are bi-directional definitions. That is, if the switcher receives the code, it will perform the instruction; and if the
instruction is performed (due to a keystroke operation on the front panel), then these codes are sent. For example, if:
0000 0001 Instruction “ Switch Groups”
1000 0010 Input #2
1000 0001 in composite video group
1000 0001 Machine #1 (master)
Was sent from the PC, then the switcher (machine #1) will switch input 2 in composite video group to its output. If the user
switched input 4 in the VGA group via the front panel keypad, then the switcher will send:
0100 0001
1000 0100
1000 0100
1000 0001 to the PC.
When the PC sends instruction #1 or #2 to the switcher, then, if the instruction is valid, the switcher replies by sending the
same four bytes to the PC that were sent (except for the first byte, where the DESTINATION bit is set high).
NOTE 3
The reply to a “ REQUEST” instruction is as follows: the same instruction and input codes as were sent are returned, and the
OUTPUT is assigned to the value of the requested parameter. The reply to the instruction #5 (what is the status of the VGA
group?):
0000 0101
1000 0000
1000 0011
1000 0001
Would be:
0100 0101
1000 0000
1000 0100
1000 0001
NOTE 4
An error code is returned to the PC if an invalid code was sent to the switcher (for example, when trying to switch an input or
a group which is greater than the highest one defined). This code is also returned to the PC if an RS-232 instruction is sent
while the machine is being programmed via the front panel. Reception of this code by the switcher will not be valid.
NOTE 5
Under normal conditions, the machine’ s present status is saved each time a change is made. The power-down save (the auto
save) may be disabled using this code. Note that each time that the machine is turned ON, the auto save function is
automatically set.
NOTE 6
This is a request to identify the switchers in a system. If the INPUT is set as 1 or 2, the machine will send its name. The reply
is the decimal value of the INPUT and the OUTPUT. For example, the reply to the request to send the machine’ s name (for
machine #001) will be:
0111 1101
1000 0000 (i.e. 128+0)
1001 0111 (i.e. 128+23)
1000 0001
If the request for identification is sent with the INPUT set as 3 or 4, the appropriate machine will send its software version
number. Again, the reply would be the decimal value of the INPUT and OUTPUT - the INPUT representing the number in
front of the decimal point, and the OUTPUT representing the number following the decimal point. For example, for version
3.5 the reply will be:
0111 1101
1000 0011 (i.e. 128+3)
1000 0101 (i.e. 128+5)
1000 0001
NOTE 7
GAIN VALUE – Number from 0 to 127
NOTE 8
Answer = Current Audio Gain (0 –127)
If the Audio Gain = 0, the MUTE button is illuminated
