A digital teleconferencing control device, system and method are disclosed for use in telecommunications. A digital conference control circuit having pulse code modulation and time division multiplexing is used in connecting a plurality of telephone subscribers together for conference purposes. When...http://www.google.es/patents/US4541087?utm_source=gb-gplus-sharePatente US4541087 - Digital teleconferencing control device, system and method
Digital teleconferencing control device, system and method
