Sony SRG-120DS Technical Manual page 20

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 camera
(address 1) from the controller (address 0) is 1h in hexadecimal. The 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 replay packet from
the camera (address 1) is 90h.
Some of the setting commands for camera 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
1
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
(MSB)
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 Byte 3
Receiver's address
0
(LSB)
Fig. 2 Packet structure
Start
Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5
bit
(LSB)
Fig. 3 Actual waveform for 1 byte.
1 1 1
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
(MSB)
1 byte
Stop
Bit 6 Bit 7
bit
(MSB)
0
Terminator
FF
1 1 1 1 1
(LSB)