If the control has been dropped on a form, make sure RTheshold > 0 and it should fire. If you are creating this form programatically, show us the code.

>Yes, but OnComm event does not fire, so I did not know when I receive the data.
>
>I then put a command button on my form :
>
>mInput = thisform.oMscomm.input,
>WAIT WIND mInput
>
>and then I really found data.
>
>Why OnComm event does not fire?
>
>
>TIA.