Using full version of uV v2.33 C51 v7.03 A51 v7.03 BL51 v5.02 None of the calls that are passed in to functions as callbacks are listed in the "INTRABANK CALL TABLE OF MODULE" section of the M51 file. Only those that are not in the common area and are called directly. I have also verified using the debugger that the function address is stored not the expected banking function. Thanks for any ideas!