Inhaltsverzeichnis
ETK 47
Single tone combination teleprinter Mod. 47 / ETK 47; manufactured by 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 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 radio transmission with interference) leads to the mutilation of the message and encrypted communication is impossible, the text in the 14 segment code can usually still be deciphered without any problems even if one segment fails due to transmission.
The ETK 47 was the first model of the successful tape teleprinter ETK, which was initially used on wired teletype connections. Only the model ETL R-55 allowed more reliable transmission over the airwaves thanks to improved filters.
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
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.
Technical principle
Tube assembly
Development
To replace the Teletypewriter 34, the old teletype system comprised a total of eight crates and in addition a petrol generatort, Dr E. Gretener developed the ETK single-tone combination teleprinter after 1942 at his own risk.
In contrast to the classic teleprinter, the ETK was based on its own combination alphabet; all letters were composed of 14 character elements, which were printed on a paper tape by a rotation printing head. The fact that even mutilated characters are still recognisable gives the system better error redundancy compared to teleprinters, which work with the Baudot Code CCITT No. 2.
In 1946, the first order for 50 model 47 ETK recorders was placed, and after improvements to the keyboard, the more reliable model 50 was developed.
Use
The 50 ETK recorders ordered in the first batch were used for wired teletype operation, three years later the ETK-50 model was introduced with an improved keypad after „teething troubles“ had been corrected.
Technical documentation
Further information
- The telecommunications equipment of the Swiss Army, Volume 14, The terminals from the Morse recorder to the laptop, Merker Verlag, Lucerne