Hi Yau, try this code :

**nComm=1 or 2 for comport
with thisform.MSCOMM1
.CommPort=nComm
.Settings="9600,n,8,1" && Set the baud rate
.PortOpen=.t. && Open the port
.output="A" && send A Character
.output="A"
.output="A"
.output="A"
.PortOpen=.F.
endwith

Hope this helps.
Shafid