RFX9600 does not support hardware flow control.

Assuming that variable 'label' is simply a string, you will get any response stored there. However, if you have assigned the variable 'label' as the widget for some panel on your screen, you will need to use label.label.

If the protocol is as you say, **Y8,3\r should connect input 8 to output 3. You should get some sort of response back. I suspect you may have to parse something out of that response (using String.split() or String.substring()) but assigning the response to a label is a good start.