Communication Protocol
19
9 Communication
Protocol
1
The VA-8xl or VA-16xl is compatible with Kramer’s Protocol 2000
2
(version 0.43). This RS-232 / RS-485 communication
protocol uses four bytes of information as defined below.
1st BYTE:
Bit 7 (MSB) - Defined as 0.
Bit 6
0 - for sending information to the switchers (from the PC);
1 - for sending to the PC (from the switcher).
Bits 5…0 – “INSTRUCTION”
The function that is to be performed by the switcher(s) is defined by the INSTRUCTION (see Table 6 below). Similarly, if a
function is performed via the machine’s front panel, then these bits are set according to the INSTRUCTION NO., which was
performed.
2nd BYTE:
Bit 7 (MSB) - Defined as 1.
Bits 4…0
- Channel number
Bit 5
- Left (set to 1 when referring to the left channel)
Bit 6
- Right (set to 1 when referring to the right channel)
3rd BYTE:
Bit 7 (MSB) - Defined as 1.
Bits 6…0 – 7 least significant bits of data
4th BYTE:
Bit 7 (MSB) - Defined as 1.
Bit 5
- MSB of data (7 LSBs are in 3rd byte).
Bits 4…0
- MACHINE NUMBER.
For RS-232, a null-modem connection between the machine and controller is used. For both RS-232/RS-485 interfaces the
default data rate is 9600 baud, with no parity, 8 data bits and 1 stop bit.
Table 6: Instruction Codes
Note: All values in the table are decimal, unless otherwise stated.
# DESCRIPTION
3rd
BYTE
22dec
(16hex)
SET AUDIO GAIN
Set 7 LSBs of gain value
Gain (dB) = 31.5 – (0.5x(255-DATA))
24dec
(18hex)
INCREASE / DECREASE
AUDIO GAIN
0 - increase gain
1 - decrease gain
25dec
(19hex)
REQUEST AUDIO GAIN
As in Instruction 22dec above.
When requesting both channels, the reply is:
For equal left and right gain: bits 5 = bit 6
For unequal left and right gain: bits 6 = 0; bit 5 = 1 for reply for left channel
In addition to the above, instructions 15, 18, 19, 20, 61, 62 (decimal) of Kramer’s Protocol 2000 are also fully implemented in
the unit. For instructions 18 and 19, setups 01 to 15 (decimal) are valid.
See the examples in the Table 7 below:
Table 7: Examples
COMMAND
EXAMPLES (MACHINE # 1)
16h E7h 90h 81h
Set channel 7 both left and right gain -88dB
16h AAh FFh 81h
Set channel 10 left gain -32.5dB
16h CAh COh A1h
Set channel 10 right gain 0dB
16h FOh DOh A1h
Set channel 16 both left and right gain +8dB
18h EFh 80h 81h
Increment (increase) gain on 0.5dB on left and right of Channel 15
19h CFh 80h 81h
Request gain of Channel 15 right.
If the gain is 0dB for both left and right channels, then the reply would be: 59h EFh COh A1h
19h EEh 80h 81h
Request gain of Channel 14 both left and right.
If the gain is different for the left and right channels, then, for +3dB gain in the left channel the
reply would be: 59h AEh C6h A1h
Table 8 on page 20 defines the VA-16xl Hex Codes for Gain Control (Attenuation), Table 9 on page 21 defines the VA-16xl
Hex Codes for Gain Control (Amplification), and Table 10 on page 21 defines the Channel Number Codes.
1 VER-0.1
2 See the Technical Support section of our Web site: http://www.kramerelectronics.com