An electronic keyboard musical instrument is operated by a main system computer in a manner dependent on the settings of input elements. A plurality of tone modules are used, each of which comprises a subsystem computer including a subsystem bus, a memory and a microprocessor. Data is exchanged between...http://www.google.com/patents/US4644840?utm_source=gb-gplus-sharePatent US4644840 - Electronic keyboard musical instrument and a method of operating the same
