====== ETK 50 ======
**Single tone combination teleprinter model 50** / **ETK 50**; manufactured by [[Gretag|Dr. Edgar Gretener AG, Zurich]].

After the Second World War, Dr E. Gretener developed the tape teleprinter "Einton - Kombinationsschreiber" (ETK) on his own initiative; his radio teletype method is based on a specifically developed 14-element code. In contrast to the Baudot Code CCITT No. 2, the text in the 14 segment code can usually still be deciphered without any problems even if one segment fails due to a transmission failure.

In contrast to the first version [[ETK 47]], the keypad on model 50 was improved.

The ETK was initially used on wired teletypewriter connections, only the [[ETK-R55]] version (model 55) allowed wireless transmission thanks to  improved filters.\\ 
{{:images:gretag-etk-50.jpg?direct&600|ETK model 50}}
===== Technical data =====
  * [[Principle]]: Single tone combination teleprinter
  * [[Operation modes]]: Single-tone telegraphy, 1500 Hz, 93 baud, max. 300 ZpM

==== Power supply ====
  * [[Mains operation]]: 110-250 V AC mains
  * 12 V direct current

==== Dimensions ====
  * mm, kg

==== Accessories ====
  * As standard antenna 

{{:images:gretag-etk-50-front.jpg?direct&500|ETK model 50}}
===== Mounting material =====
The **ETK** consists of a transport case with an integrated amplifier and the actual teletypewriter.

The amplifier in the transport case is connected to the receiver's AF output and the transmitter's microphone input. A thick multipole cable connects the amplifier to the teletypewriter.

In contrast to the previous model, the keypad was revised and "teething troubles" of the early models were eliminated.\\ 
{{:images:gretag-etk-50-geschl.jpg?direct&330 |ETK model 50}} {{ :images:gretag-etk-50-schreiber.jpg?direct&330|ETK Model 50, Schreibeerk}}

===== Technical principle =====

==== Tube assembly ====

==== Development ====
To replace the [[Schreibtelegraph 34|Teletypewriter 34]], the old teletypewriter system cosisted of a total of eight crates and an additional petrol generator, Dr E. Gretener developed the single tone combination teleprinter [[ETK]] in the last years of the war at his own risk.

A first order of 50 ETK model 47 single-tone combination recorders was delivered in 1947 for wired use, and after improvements to the keyboard, the more reliable model 50 was developed.

==== Use ====
Like the Model 47, the ETK 50 was intended for wired use.

{{gallery>:images?gretag-etk-50*.jpg&0&80x80&lightbox&showtitle&titlesort}}

===== Technical documentation =====
  * {{ :manuals:etk-r55-gretag-small.pdf |Funktionsbeschreibung ETK-R Fernschreibanlage Mod. 55, Dr Gretener AG}}
  * {{ :manuals:etk-r55-gretag-prospekt.pdf |ETK teleprinter, Dr Gretener AG}}

==== Further information ====
  * The Telecommunications Equipment of the Swiss Armed Forces, Volume 14, Endgeräte vom Morseschreiber zum Laptop, Merker Verlag, Lucerne
  * [[http://armyradio.ch/radio-d/gretag-etk-50.htm|Gretag ETK 50 on www.armyradio.ch]]
  * [[https://www.hamfu.ch/de/geraete/geraet.php?id=58|Gretag ETK 50 on the Hamfu website]]
  * [[https://www.radiomuseum.org/r/gretener_ein_ton_kombinationsschr.html|Gretag ETK on the website of www.radiomuseum.org]]