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 comprises the sender's and receiver's addresses. For example, the header of the packet sent
to the unit (address 1) from the controller (address 0) is 81H in hexadecimals. Packet sent to the unit
(address 2) is 82H.
In the command list, as the header is 8X, input the address of the unit to X. The header of the reply
packet from the unit assigned to address 1 is 90H. The packet from the unit 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.
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)
Fig. 2 Packet structure
Fig. 3 Actual waveform for 1 byte.