A master station 1 is connected with a telephone line 2. For this master station 1, a plurality of hand sets are provided. Each hand set is set to different transmitting and receiving frequencies to communicate with the master station 1. Each hand set generates from an information signal generating circuit...http://www.google.es/patents/US4741019?utm_source=gb-gplus-sharePatente US4741019 - Cordless telephone
