‎"SCHENKER, L.‎
‎Pushbutton Calling with a Two-Group Voice Frequency Code. - [FIRST DESCRIPTION OF THE PUSH-BUTTON TELEPHONE]‎

‎New York, American Telephone and Telegraph Company, 1960. 8vo. Volume XXXIX (49), January, No. 1, 1960 of ""The Bell System Technical Journal"". Entire issue offered in the original printed blue wrappers. A bit of sunning to spine and previous owner's stamp to top of front wrapper, otherwise a very nice, clean, and fresh copy. Pp. 235-255. [Entire issue: 264 pp.].‎

Reference : 43555

‎First printing of this seminal paper in which the push-button telephone is first described. Push-button telephony was considered a revolution within telecommunication. It replaced rotary dial telephones that had been in use since 1891 and the technique behind the touch-tone format is today used for all cell phones.The first prototypes were invented in 1941 by the Bell System, these were, however, never fully functional and therefore not brought to the commercial market. The research was shelved during WWII and was not prioritized until later, after the transistor had been developed and tones could be produced with electronic oscillators in the late 1950ies. The first push-button telephone reached the commercial market in 1963, though in the mid 1970ies the majority of phone users still had rotary phones.The issue contains the following papers:1. Feiner, A." Lovell, C.A. Lowry, T.N. Ridinger, P.G. The Ferreed - A New Switching Device. Pp. 1-30.2. James, D.B. Johannesen, J.D. A Remote Line Concentrator for a Time-Separation Switching Experiment. Pp. 31-57.3. Malthaner, W.A. Runyon, J.P. Controller for a Remote Line Concentrator in a Time-Separation Switching Experiment. Pp. 59-86.4. Bakanowski, A.E. Forster, J.H. Electrical Properties of Gold-Doped Diffused Silicon Computer Diodes. Pp. 87-1045. Legg, V.E. Analysis of Quality Factor of Annular Core Inductors. Pp. 105-126.6. Benes, V.E. General Stochastic Processes in Traffic Systems with One Server. Pp. 127-160.7. Unger, Hans-Georg. Round Waveguide with Double Lining. Pp. 161-167.8. Thurmond, C.D. Kowalchik, M. Germanium and Silicon Liquidus Curves. Pp. 169-204.9. Trumbore, F.A. Solid Solubilities of Impurity Elements in Germanium and Silicon. Pp. 205-233. 10. Schenker, L. Pushbutton Calling with a Two-Group Voice-Frequency Code. Pp. 235-255.‎