United air lines' reperforator switching system

Fast and efficient operation of the United Air Lines' system has been made possible by the installation of 9 000 miles of communication network, which handles all information dealing with planes, passengers, cargo, weather, etc. The relaying of telegraph traffic on this network is performed at 7 major centres which use the method of reperforator switching, an incoming message being recorded by a printer perforator which is then passed through a transmitter which automatically retransmits the message. Illustrations are given of the instruments used at these switching centres and of the receiving teleprinters at other stations. The general layout of a switching centre is shown in photographs of the centre at Portland, Oregon.