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Analysis Of Swiss ETK Teletypewriter

Report Number: WADC TR 52-266
Author(s): C. P. Seymor, L. B. Rosenberg
Corporate Author: Wright Air Development Center
Date of Publication: 1952-09
Pages: 35
PB Number: PB128602
AD Number: AD0015850
Original AD Number: 15850

An elemental printing technique for error indication in teletypewriter systems was devised by the Dr. Edgar Gretener A. G. of Zurich in which a character consists of a combination of marking bits. Each bit is the result of a finite electrical signal. The machine operated on the asynchronous start-stop principle and utilized a conventional electromechanical printing control system. The character was formed by printing a combination of 14 sign elements, of which a maximum of 5 impressions were required to print any complete character. The rotational torque impressed on the type wheel and another component element was supplied by a 12-v governed motor. A primary power supply of either 110 or 245 vac, or 12 vdc can be used. The equipment may be used with land lines or in conjunction with a radio-telephone circuit, since the output is in the form of an audio tone. The sequence of operation, the functioning of parts, and the operation of a line unit are described in detail.

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