Inhaltsverzeichnis
ETK (prototype)
Prototype of the Single tone combination teleprinter / ETK; manufactured by Dr. Edgar Gretener AG, Zurich.
After the Second World War, Dr E. Gretener developed the single tone combination teleprinter „Einton - Kombinationsschreiber“ (ETK) on his own initiative; the radio teletype transmission is based on a specially developed 14-element code. In contrast to the Baudot Code CCITT No. 2, in which even the failure of one character (for example in a wireless transmission with interference) leads to the mutilation of the message, 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.\
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
- Direct current 22-26 V
Dimensions
- mm, kg
Accessories
Plant material
The ETK consists of a transport box with the electronics (amplification and level adjustment) and the actual teletypewriter with keyboard and integrated tape printer inserted in the lower section.
The amplifier in the transport box is connected to the telephone network. A thick multipole cable connects the amplifier electronics to the teletypewriter.
As the drive motor could be operated from the AC mains or with direct current and the anode voltage for the amplifier was obtained from a second winding on the motor acting as generator, a separate mains supply unit was no longer required for operation.
The first installations of the teletypewriter developed by Dr. Gretener AG on its own initiative was introduced for wired teletype operation with the designation ETK 47.
Technical principle
Tube assembly
Development
To replace the Teletypewriter 34, Dr E. Gretener developed the ETK single-tone combination teleprinter in the last years of the war at his own risk.
A first batch of 50 ETK model 47 single-tone combination teleprinters for wire-bound use was delivered in 1947; after improvements to the keyboard, the more reliable model 50 was developed.
Use
Technical documentation
Further information
- The Telecommunications Equipment of the Swiss Armed Forces, Volume 14, The Terminals from the Morse Recorder to the Laptop, Merker Verlag, Lucerne