Hi Qma15jo , thanks for asking this questions. Really it’s a challenging task. As I don’t have an access to 3-Com 4200 Switch, I tried to answer your question based on the documentation available from the 3-Com website in my ITKE Blog. DO check the answer at this link http://itknowledgeexchange.techtarget.com/network-technologies/how-to-configure-trunking-between-a-cisco-catalyst-and-a-3com-superstack/
If you have any comments do leave your comments in the blog page. As far as trunking between Cisco Catalyst Switch and a 3-Com 3300 Switch is concerned its tested and working fine with me in one of our sites.