Liu,

Then you have to transmit both bytes per character right?

What happens if you just run this code do you see all possible 256 bytes show up on the other serial device?

for i = 0 to 255
   mscomm.olemscomm.object.output = chr(i)
endfor

>I'm sure that it set right
>mscomm.olemscomm.object.commport=1
>mscomm.olemscomm.object.settings="9600,n,8,1"
>
>Because WIN98 Chinese operating is one character use two bytes
>
>If transmit a bigger 128 than receive the data is 0