SYSTEM INCORPORATING PROGRAM FOR INTERCEPTING AND INTERPRETING OR ALTERING COMMANDS FOR GENERATING I/O ACTIVITY FOR ENABLING REAL-TIME USER FEEDBACK BY SENDING SUBSTITUTE CHARACTERS TO MODEM

A system for allowing application programs to be written that can communicate over a multitude of transmission media without requiring the application program to be rewritten or reconfigured. This system includes a hook program which resides between the application programs and the operating system upon which the application programs run. The hook program intercepts information targeted for the operating system and the transmission medium and transforms it into the desired format, ensuring that the appropriate content is contained in the transmission. This system also intercepts data being sent to the application programs from the operating system while allowing interrupts to be sent from the transmission medium to the application programs without being intercepted by the hook program.