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10 Communication Protocol
This protocol, which enables RS-232 communication between the
VS-402xl/VS-602xl and the PC, uses 4 bytes of information, and data is at
9600 baud, no parity, 8 data bits and 1 stop bit.
MSB
DESTINATION
0
D
7
6
1st byte
1
I6
7
6
2nd byte
1
0
7
6
3rd byte
1
0
7
6
4th byte
1st BYTE:
Bit 7 – Defined as 0.
D – " DESTINATION" :
1 - for sending to the PC (from the switcher).
N5...N0 – " INSTRUCTION"
The function that is to be performed by the switcher(s) is defined by the INSTRUCTION (6 bits). Similarly, if a function is
performed via the machine's keyboard, then these bits are set with the INSTRUCTION NO., which was performed. The
instruction codes are defined according to the table below (INSTRUCTION NO. is the value to be set for N5...N0).
2nd BYTE: Bit 7 – Defined as 1.
I6...I0 – " INPUT" .
When switching (ie. instruction codes 1 and 2), the INPUT (7 bits) is set as the input number which is to be switched.
Similarly, if switching is done via the machine's front-panel, then these bits are set with the INPUT NUMBER which was
switched. For other operations, these bits are defined according to the table.
3rd BYTE:
Bit 7 – Defined as 1.
O6...O0 – " OUTPUT" .
When switching (ie. instruction codes 1 and 2), the OUTPUT (7 bits) is set as the output number which is to be switched.
Similarly, if switching is done via the machine's front-panel, then these bits are set with the OUTPUT NUMBER which was
switched. For other operations, these bits are defined according to the table.
4th BYTE:
Bit 7 – Defined as 1.
Bit 5 – Don't care.
OVR – Machine number override.
M4...M0 – MACHINE NUMBER.
Used to address machines in a system via their machine numbers. When several machines are controlled from a single serial
port, they are usually configured together with each machine having an individual machine number. If the OVR bit is set, then
all machine numbers will accept (implement) the command, and the addressed machine will reply.
For a single machine controlled via the serial port, always set M4...M0 = 1, and make sure that the machine itself is
configured as MACHINE NUMBER = 1.
20
Communication Protocol
Table 8: Protocol Definitions
N5
5
I5
5
0
5
0
5
0 - for sending information to the switchers (from the PC);
INSTRUCTION
N4
N3
4
3
INPUT
I4
I3
4
3
OUTPUT
0
0
4
3
0
M3
4
3
N2
N1
2
1
I2
I1
2
1
0
O1
2
1
MACHINE NUMBER
M2
M1
2
1
KRAMER ELECTRONICS, LTD.
LSB
N0
0
I0
0
O0
0
M0
0
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