STX and
ETX usually refer to ASCII control characters
Control character - Wikipedia, the free encyclopedia[
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An ASCII control character can't be displayed, thus to show you where to put them, it is a common usage to show them as
[STX] and
[ETX] but you have to replace them by their ASCII codes.
It means that
[STX] must be replaced by a single ASCII character of value
0x02.
It means that
[ETX] must be replaced by a single ASCII character of value
0x03.
It is also possible that
IpAddr should be replaced by something else. Only sensor documentation will tell you.
It is a good idea to look for tutorials and users forums.