Appendix A: Camera Control Protocol - Sennheiser SDC 8200 AO System Manual

Appendix A: Camera control protocol

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Appendix A: Camera control protocol
The SDC 8200 conference and interpretation system supports camera con-
trol. The central unit sends a control command to the connected camera
control:
when a delegate or chairman unit is activated,
when a delegate or chairman unit is deactivated,
when all active microphones are deactived one after the other,
when all active microphones are deactived simultaneously
(priority function),
every 5 seconds for synchronization.
These commands are evaluated by the camera control which then auto-
matically aims the camera at a speaker and adjusts the focus.
The camera control must be connected to the SDC 8200 CU central unit's
COM 2 interface (RS 232 connection). The settings for the communications
port for camera control are:
Bits per second: 19,200
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None
The syntax of the commands
All commands sent by the SDC 8200 CU central unit start with a "%" sign.
The last character is a character which states the end of the transmission.
Just before the end-of-transmission character, there are four characters
within the command sent to the camera control which account for the CRC
checksum.
STX "%"
Start of Transmis- Data of the com-
sion Character mand
(0x25 = "%")
The CRC checksum is in uppercase hexadecimal form while all other num-
bers are in decimal form.
data CRC
16 bit sum of the
ASCII characters
between STX and
CRC
ETX
End of Transmis-
sion Character
(0x0D)