@TomHoe said in Int16 to QByteArray:

didn't knew that '!' is the same as 0x21..

See http://www.ascii-code.com/

'!' == 33 == 0x21 == 0b00100001

@TomHoe said in Int16 to QByteArray:

Is there a way to rewrite it to regular hex codes ? Or does every controller understand this notation ?

Again, '!' == 33 == 0x21 == 0b00100001

Those are different ways of displaying the same bytes. The controller does not see any "hex" or "notation"; it only sees the sequence of 0's and 1's.

I recommend you learn about how bits/bytes are stored in computer memory: http://statmath.wu.ac.at/courses/data-analysis/itdtHTML/node55.html