FACSIMILE TRANSMITTER UNIT

摘要

A facsimile transmitter comprises a rotatable drum and a sensor for detecting dark-light variations in a document mounted on the drum. A facsimile receiver comprises a rotatable drum and a writing stylus for reproducing dark-light variations on a copy medium mounted on the drum. Prior to transmission of modulated signals representing the dark-light variations in the document, synchronizing signals are transmitted from the transmitter to the receiver. The synchronizing signals comprise pulses of selected and controlled frequency duration and time lapse therebetween to signal the transmission mode. The various modes signaled include different and variable scanning rates, different frequency bandwidths and different forms of modulation.