Hi Shafid this is my old code 5 years ago just try to check if can use any. Because its not that documented. I will email you the class if can make it work. As I have notice before the BAUD rate of your Cash Register is Very important. in this case "300,n,8,1" is the setting base on the hardware specification

Local lcOldError,llIsError
lcOldError=ON("ERROR")
llIsError=.f.
On error llIsError=.t.


With This.MSCOMM
	.CommPort = oApp.portNum
	.settings="300,n,8,1"


	If !llIsError
		.PortOpen = .t.
	Endif

	If !llIsError
		.Output = "A"
	Endif

	If !llIsError
		.PortOpen = .f.
	Endif

Endwith

If llIsError=.t.
	Messagebox("Error Connecting to Port" + chr(13)+chr(10)+MESSAGE()+chr(13)+chr(10)+;
		"Please check the port setting. Tools-->Options ",0,"Port Setting")
Endif

this.Iserror=llIsError
llIsError=.f.
On error &lcOldError