To Keil support.. Some time back I was told that Keil was working on a fix for uVision that would allow me to use the C164CI serial port without uVision stealing the interrupt vector from me. I had to add a MAX3110E to my last project so I could do interrupt driven serial IO during development. I am again confronted with the same problem. It seems to me that the serial port is important enough resource to allow the user access to it. If anyone else has solved this problem I would appreciate any help. I am aware of the simulated serial port available if I burn the Monitor into ROM, I really don't want to burn a board just for this fix. Thanks for the great forum Eric P.S I am using uVision V2.03 and my support ended May 2000 but I never had this problem solved.