File:Bell telephone magazine (1922) (14569657630).jpg

Identifier: belltelephonevol21mag00amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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ished asentence. In fact, if one speakershould try to interrupt the other, hisattempt will meet with failure becausethe emergency radio terminal will pre-vent it. i HE questions might well be asked,Why all these relays? Why not justconnect the radio transmitter and re-ceiver to the wire lines and go ahead and talk? There is, of course, adefinite—though somewhat technical—reason. If both radio transmitter and radioreceiver were connected together, thenobviously everything that came out ofthe radio receiver would go into theradio transmitter and be sent back asan echo to the other end of the line.Furthermore, if the other radio ter-minal was similarly arranged, thisecho would come back again behindthe original word and continue tochase itself around this closed loopuntil it became dissipated. If theradio system amplified the signals, thecircuit not only would sound hollow,like shouting into a rain barrel, but itactually would build up into a howl 234 Bell Telephone Magazine NOVEMBER
Text Appearing After Image:
Components of an Emergency Radio Telephone LnitThe parts and their functions are described on the opposite page 19^ Bridging Breaks ix Wire Circuits 235 and prevent any further conversation.The relays effectively prevent suchconditions by making the radio link aone way at a time circuit. In fact,the arrangement does more than this,since only one antenna is required forthe radio equipment at each terminaland but a single radio channel isneeded for both terminals. The Component Parts OOME of the essential electrical partsof the Bell Systems emergency radiotelephone equipments have been sug-gested by the discussion of the dia-gram. In the photograph on page234, the radio unit is shown nearthe top center. The framework, witha hand rail to furnish a substantialbase and facilitate its transportation,mounts at the top the radio trans-mitter, and in the lower half is theradio receiver. The dust-cover doorof the radio transmitter is open, as itwould be during actual operation. To the left of t

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