1. First of all
I would change
int16 ch; /* Data received from the Serial port */
to
char ch; /* Data received from the Serial port */
2. What do you send from PLC, ASCII 0-9 or a byte of 0-255 ( ie an int from 0x00 to 0xffff? If you are send a binary value, you need to convert it to ascii string to display.
3. Have you use hyperterminal to check what you are sending from the PLC?
4. As I menention in my last post, have you check as what list on the steps? which step does it project failed?
