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STX = start transmit char (0x25 = ‘%’)
ETX = end transmit char (0x0D)
CRC = 16 bit sum of the ASCII characters between STX
and CRC
We will adopt a certain notation to explain the messages sent. All
separate entities in a message are represented between curly
brackets. If the contents of such an entity is also between quotes (‘
‘) then this means that this is a literal string. Otherwise it describes
the logical entity. A logical entity will also contain a number
between brackets. This number states how many characters the
entity will exist of. If the subtext
1+
is attached to the entity
between curly brackets, then this means that one or more
occurrences of this entity may occur.
Maybe this notation seems a little hard to comprehend at first, but
some examples should clarify them.
Whenever a microphone of a delegate or the microphone of the
president is activated, then a command is sent to the camera
control. Whenever an active microphone is deactivated, another
command is sent to the camera control.
The microphone of the president is activated:
{‘%’}{‘P’}{Microphone number (4)} {CRC (4)}
The microphone of the president is deactivated:
{‘%’}{‘p’}{Microphone number (4)} {CRC (4)}
The microphone of a delegate is activated:
{‘%’}{‘M’}{Microphone number (4)} {CRC (4)}
The microphone of a delegate is deactivated:
{‘%’}{‘m’}{Microphone number (4)} {CRC (4)}
The remaining commands are control commands.
At a time-interval of around 5 seconds a synchronization
message is sent to the camera control. The message contains all
the numbers of the active microphones or the number 0 to
stipulate that there are no microphones active.
{‘%’}{‘S’}{Microphone Number (4)}
1+
{CRC (4)}
All active microphones are deactivated simultaneously.
{‘%’}{‘V’}{‘0000’}{CRC (4)}
Examples
If the president microphone is activated, and the president
microphone has the number ‘0001’ then the following message is
sent: %P00010111
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