A Carrier-Operated Echo Suppressor and Control Device

Of the numerous distortions affecting high quality facsimile reception, noise and echo represent the most troublesome offenders. This paper describes a device which fills the critical need for suppression of noise and echo currents on two-way multipoint facsimile networks. Laboratory test data as well as operational performance results, gathered during field trials of two prototype units, are presented. Additional applications for the device, including TONLOC, disabling of compandors during picture transmission, and possible application to data transmission systems are discussed.