37
Command List
VISCA Communication Specifications
address 1 is 90H. The packet from the camera assigned
address 2 is A0H.
Some of the commands for setting cameras can be sent
to all devices at one time (broadcast). In the case of
broadcast, the header should be hexadecimal 88H.
When the terminator is FFH, it signifies the end of the
packet.
Packet (3 to 16 bytes)
Message (1 to 14 bytes)
Header
Byte 1
Byte 2
Byte 3
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
1
0
FF
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3
Bit 2
Bit 1 Bit 0
(LSB)
1
1
1
1
1
1
1
1
Sender’s
address
Receiver’s address
Terminator
VISCA Equipment
RXD
TXD
RXD
TXD
RXD
TXD
VISCA Controller
RXD
TXD
VISCA network structure
Notes
• Connect the serial output from the PC to the serial
input of camera 1, then connect the serial output of
camera 1 to the serial input of camera 2, the serial
output of camera 2 to the serial input of camera 3,
and the serial output of camera 3 to the serial input of
the PC. (Up to seven cameras may be connected.)
• Power on all the units connected in series.
• Mixed existence of RS-232C and TTL signal levels is
not allowed.
Camera 1
Camera 2
Camera 3
VISCA Packet Structure
The basic unit of VISCA communication is called a
packet. 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 FCB
camera assigned address 1 from the controller (address
0) is hexadecimal 81H. The packet sent to the camera
assigned address 2 is 82H. In the command list, as the
header is 8X, input the address of the camera at X. The
header of the reply packet from the camera assigned
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