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VISCA Communication Specifications
VISCA packet structure
The basic unit of VISCA communication is called a packet (Fig. 2). The first byte of the packet is called the
header and the packet comprises the sender's and receiver's addresses. For example, the header of the
packet sent to the camera (address 1) from the controller (address 0) is 81H in hexadecimals. Packet sent
to the camera (address 2) is 82H.
In the command list, as the header is 8X, input the address of the camera to X. The header of the reply
packet from the camera assigned to address 1 is 90H. The packet from the camera assigned to address
2 is A0H.
Some of the setting commands can be sent to all devices at one time (broadcast) *.
In the case of broadcast, the header should be 88H in hexadecimal.
When the terminator is FFH, it signifies the end of the packet.
* The broadcast function is not available for VISCA over IP.
Header
Sender's
address
Note
Fig. 2 shows the packet structure, while Fig. 3 shows the actual waveform. Data flow will take place with
the LSB first.
Packet (3 to 16 bytes)
Message (1 to 14 bytes)
Byte 1
Byte 2
Receiver's address
Fig. 2 Packet structure
Start
bit
Fig. 3 Actual waveform for 1 byte
Byte 3
1 byte
4
Terminator
Stop
bit
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