quadruplex

• Thus by combining instruments that respond only to variation in the strength of current from the distant station, with instruments that respond only to the change in the direction of current from the distant station, and by grouping a pair of these at each end of the line, the quadruplex is the result. —  Edison, His Life and Inventions
• The working efficiency of the quadruplex, therefore, with the apparatus in good working condition, depends entirely upon the skill of the operators employed to operate it. —  Edison, His Life and Inventions
• It was obviously a characteristically shrewd move on the part of Mr. Gould to secure an interest in the quadruplex, as a factor in his campaign against the Western Union, and as a decisive step toward his control of that system, by the subsequent merger that included not only the Atlantic ; Pacific Telegraph Company, but the American Union Telegraph Company Nor was Mr. Gould less appreciative of the value of Edison's automatic system. —  Edison, His Life and Inventions
• For his quadruplex system, Mr. Edison utilized this fact in the construction of a rheostat or resistance box. —  Edison, His Life and Inventions
• The earlier years of his inventive activity, while productive of many important contributions to electrical industries, such as stock tickers and printers, duplex, quadruplex, and automatic telegraphs, were not marked by the turmoil of interminable legal conflicts that arose after the beginning of the telephone and electric-light epochs. —  Edison, His Life and Inventions

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