Some days ago I had a problem (posted in this ng) and today I found
the solution, but I cannot explain very well how (and why) it does
work now.

The problem:
In a windows form I receive and display data (packet of bytes) coming
from a RSR232 port (100 byte per second).
The problem: when I resize the form (a MDI child) I get a CRC error
for the incoming data, this means the byte packet was damaged!

The solution:
I replaced the Server Timer used to poll the serial with a Windows
Timer

A server timer should work in a own thread and for this reason more
appropriate foot data polling! Or am I not understanding the
difference?

Thank you for your reply.

May I ask why you are polling?  The MSCOMM control is event driven, you will
have a much more reliable solution if you utilise this.

Nick.

The serial device answers when I send the char "s". So I have to send
a char each time interval:

Private Sub tmrADC_Elapsed(....) Handles tmrADC.Elapsed
            If MSComm.PortOpen Then
                MSComm.Output("s")
                Do Until MSComm.InBufferCount >= 10
                    DoEvents() (??? i do not know if is ok)
                Loop
                ProcessInput(MSComm.Input)
            Else
                tmrADC.Stop()
            End If
    End Sub