Niklas Karlsson wrote:Ok so if it is a checker, what can be the wanted return value?
The checksum. That's how they work.
The normal thing is that something, somewhere sends (or reads) the checksum first, and then compares the result with what it
expects it to be.
Not knowing the RS232 protocol in detail, I can't tell you
how that's done, but that's the general principle.
Winston