Editing Teleprinter (section)

=== Gretag ===

The Gretag ETK-47 teleprinter developed in Switzerland by [[Edgar Gretener]] in 1947 uses a 14-bit [[start-stop transmission]] method similar to the 5-bit code used by other teleprinters. However, instead of a more-or-less arbitrary mapping between 5-bit codes and letters in the [[Latin alphabet]], all characters (letters, digits, and punctuation) printed by the ETK are built from 14 basic elements on a print head, very similar to the 14 elements on a modern [[fourteen-segment display]], each one selected independently by one of the 14 bits during transmission. Because it does not use a fixed character set, but instead builds up characters from smaller elements, the ETK printing element does not require modification to switch between Latin, Cyrillic, and Greek characters.<ref>{{cite web |title=Gretag ETK-47 14-bit teleprinter system |website=Crypto Museum |date=2016-07-04 |url=https://www.cryptomuseum.com/telex/gretag/etk47/}}</ref><ref>{{cite web |url=http://www.jproc.ca/crypto/etk_series.html |title=ETK teletype equipment series}}</ref><ref>{{cite web |author=F. Dörenberg |url=https://www.nonstopsystems.com/radio/hellschreiber-modes-other-mfrs-non-UK.htm#ETK |title=Other manufacturers of teleprinter machines that use the Hellschreiber principle |at=Dr. Edgar Gretener AG (Gretag)}}</ref><ref>{{cite web |url=https://www.nsa.gov/Portals/70/documents/news-features/declassified-documents/friedman-documents/patent-equipment/FOLDER_543/41781009082006.pdf |title=The Hagelin - Gretener Cipher Teleprinter}}</ref>