A facsimile transmission control system comprising a transmitting side and a receiving side facsimile device, characterized in that the transmitting side facsimile device transmits a calling signal for calling the receiving side facsimile device, when the transmitting side receives a response signal...http://www.google.com/patents/US4736249?utm_source=gb-gplus-sharePatent US4736249 - Facsimile transmission control system
