User's Manual
VS-66HN - Kramer Protocol 2000 
25 
10  Kramer Protocol 2000 
The Kramer Protocol 2000 RS-232/RS-485 communication uses four bytes of 
information as defined below. All the values in the table are decimal, unless 
otherwise stated. 
MSB 
LSB 
1st Byte 
DESTINATION 
INSTRUCTION 
0 
D 
N5 
N4 
N3 
N2 
N1 
N0 
7 
6 
5 
4 
3 
2 
1 
0 
2nd Byte 
INPUT 
1 
I6 
I5 
I4 
I3 
I2 
I1 
I0 
7 
6 
5 
4 
3 
2 
1 
0 
3rd Byte 
OUTPUT 
1 
O6 
O5 
O4 
O3 
O2 
O1 
O0 
7 
6 
5 
4 
3 
2 
1 
0 
4th Byte 
MACHINE NUMBER 
1 
OVR 
X 
M4 
M3 
M2 
M1 
M0 
7 
6 
5 
4 
3 
2 
1 
0 
1st Byte:  Bit 7 – Defined as 0 
D – DESTINATION: 
0 – Sends information to the switchers (from the PC) 
1 – Sends information to the PC (from the switcher) 
N5…N0 – INSTRUCTION 
The 6-bit INSTRUCTION defines the function performed by the switcher(s). If a function is performed using the 
machine’s keyboard, these bits are set with the INSTRUCTION NO. performed. The instruction codes are defined 
according to the table below (INSTRUCTION NO. is the value set in N5…N0). 
2nd Byte:  Bit 7 – Defined as 1 
  I6…I0 – INPUT 
When switching (i.e. instruction codes 1 and 2), the 7-bit INPUT is set as the input number to be switched. If switching is 
done using the machine’s front panel, these bits are set with the INPUT NUMBER switched. For other operations, these 
bits are defined according to the table. 
3rd Byte:  Bit 7 – Defined as 1 
  O6…O0 – OUTPUT 
When switching (i.e. instruction codes 1 and 2), the 7-bit OUTPUT is set as the output number to be switched. If 
switching is done using the machine’s front panel, these bits are set with the OUTPUT NUMBER 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 
This byte is used to address machines in a system by their machine numbers. When several machines are controlled 
from a single serial port, they are usually configured together and each machine has an individual machine number. If 
the OVR bit is set, then all machine numbers accept (implement) the command and the addressed machine replies. 
When a single machine is controlled over the serial port, always set M4…M0 to 1, and make sure that the machine itself 
is configured as MACHINE NUMBER = 1. 










