A multimedia control system which may be expanded without creating or modifying source code. The system is based on a master programmable multimedia controller. The master programmable multimedia controller has a list of unique identifiers that indicate valid subordinate programmable multimedia controllers that are eligible to become part of the system. One or more subordinate programmable multimedia controllers having a matching unique identifier to a unique identifier on the master's list may be added to the system to provide additional control ports, increase audio or video processing or switching capacity. A method is provided for determining whether a particular subordinate programmable multimedia controller may be added to the system.