Try turning down your baudrate to 4800. Also use Even parity. check your transmit settings on the PC and see if you can select "remove control characters". I am not sure about changing the delay time on the control. But you should have an option on your PC for Transmit Trigger. Select Xon. Then get your PC ready to send the program. Your PC will wait for a control character from the CNC before transmitting. You then can go to the control and command the control to start receiving.