I have a device on a usb port which I can successfully write directly to. However, I am experiencing difficulties reading directly from the port.

Everything below works (the commands go to the device) until it gets to the readfile portion. The device is sending data back but the readfile() is not capturing it. Any ideas?

*--lc_DeviceName is returned from SetupDiGetDeviceInterfaceDetail
lh_Device = CreateFile(lc_DeviceName, ; 
      GENERIC_READ + GENERIC_WRITE ,; 
      FILE_SHARE_READ + FILE_SHARE_WRITE, 0, OPEN_ALWAYS,; 
      FILE_ATTRIBUTE_NORMAL + FILE_FLAG_SEQUENTIAL_SCAN, 0) 

IF (lh_Device != INVALID_HANDLE_VALUE)	&& Later test using DeviceIoControl From Lh_Device also

   lw_Buffer = SPACE( MAX_PATH )
   lcSendValue = [! U1 MCR 80 T1 T2] + CHR(10) + CHR(13) && a command the USB device recognizes
   lnWritten = 0

   IF WriteFile(lh_Device, lcSendValue, LEN(lcSendValue),@lnWritten,0) <> 0 && 0 is failure

        *!!!! Success - the device responds to the command sent
        *!!!! Now capture the data returning from the device (the response)

	lcReadBuffer = REPLICATE(" ",MAX_PATH)
	lnBytesReturned = 0
	lnCounter2 = 0
        
        *--Latest attempt is to loop through a read for awhile
	DO WHILE lnBytesReturned == 0
		lncounter2 = lncounter2 + 1
		IF ReadFile(lh_Device, @lcReadBuffer, LEN(lcReadBuffer), @lnBytesReturned, 0) <> 0
		   lncounter = 0
		   DO WHILE lncounter < 50
			lncounter = lncounter + 1
		        DOEVENTS
			IF !EMPTY(MakeANSI(lcReadBuffer))
			    ? lcReadBuffer
			    ? MakeANSI(lcReadBuffer)
			ENDIF
		   ENDDO
		   * ADD GetQueuedCompletionStatus()
		ENDIF
		IF lncounter2 = 100
		   EXIT
		ENDIF
	ENDDO
   ENDIF
   CloseHandle( lh_Device )
ENDIF