A set top box for digital audio/video interactive decoding in an interactive television system is disclosed. The set top box includes means for connecting to an interactive television system as well as means for connecting to a television set. The set top box includes a CPU on which is run a real time operating system. The operating system is comprised of modules of code. Each module of code makes up a portion or component of the overall system. A description record is created for each module which includes the device type and device name and can also include the device parameters. The description records are stored in a configuration description block. The description block is stored in RAM and can be updated at any time. If a new system module is downloaded from the interactive television system, a description record corresponding to the new module can be added to the description block. Thus, real time system upgrades are accomplished without the need for user interaction and without the need for restarting the system. The updated system modules can either be stored in RAM for session only upgrades or the upgrade modules can be stored in FLASH memory for extended updating.