Carrier current telephony and telegraphy

Abstract

Continuing its series of classic papers of the past, the PROCEEDINGS turns this month to the AIEE TRANSACTIONS of 1921 f o r a major contribution to the field of telephony, a contribution that to an important extent was made practicable by developments in the field of radio. Because of the unusual length of the paper (the original printing required 95 pages), extensive design and equipment details have been omitted and only the jirst half and the closing paragraphs of the paper are presented below.Thus there follows a n epic paper which, although it is old, will be neul to ut least 99 per cent of the present generation of I E E E members. -The EditorSummury--This paper briefly outlines fist the history of the development of carrier multiplex telegraphy and telephony. The fundamental principles underlying particularly the newer developments of the art are then discussed. Consideration is likewise given to the propagation characteristics of open-wire lines, including those containing intermediate lengths of cable. Commercial types of apparatus and actual installations are then described and a brief statement made as to further applications of the art.