I am planning to purchase a arm based board and run QNX non commercial OS. Is debugging done via rs232 can i use usb what are my options for debugging. I have to know my options before I purchase board I am a novice to embedded systems I plan to learn from home with my embedded board and QNX non commercial. 
What version of QNX do you plan to use, there is no non-commercial anymore, only a 30 days eval.
well I was told there was a non commercial version if not I will have to use linux. If there is a 30 day trial wont that be ample time to build OS or will OS built expire in 30 days? What are my options for debugging? rs232? or USB whats my choices?
You will be able to run the OS on your target forever but you will not be able to use the TOOLS needed to create the image or create programs. You can use rs232 for debugging as for USB i don’t know, jtag is possible as well I believe.
Seems to me you’d be better of using linux for this if you are an hobbyist.