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Voice, telegraphy and data encryptors

ELCRO was a family of encryption/decryption devices, initially developed by Siemens in München (Munich, Germany), for a wide variety of applications, including voice, data, facsimile and tele­printer traffic. Development and sales of the devices was later taken over by ANT and eventually by Rohde & Schwarz (R&S), who continues to develop and market the devices to this day (2018).

ELCRO family
In the ELCRO family, each type of device has a generic name that consists of the word ELCRO with a three-letter suffix appended at the end, such as VOX or TEL. The name can be written in upper case (e.g. ELCROVOX 1/3) or in lower case (e.g. Elcrovox 1/3) The following types are known:

  • Narrow-band voice encryption
  • Telegraphy (telex) encryption
  • Data encryption (used in AUTOKO communication system)
  • ISDN voice and data encryption (up to 64 kbps)
  • Trunk encryption (multiplex) up to 2 Mbps
ELCROVOX was a series of narrow-band speech encryptors used over radio or via telephone (land) lines. Elcrovox 1/3 was a military voice encryptor that used a proprietary Siemens encryption algorithm. Keys were loaded into the device by means of a short piece of punched paper tape.

It was succeeded by the much smaller Elcrovox 1/4 that used the secret NSA SAVILLE encryption algorithm. Keys were loaded into the device by means of a DS-102 fill unit, such as the KYK-13 or the KOI-18. The Elcrovox 1/4 was interoperable with the American STU-II crypto phone.

Known ELCROVOX devices
ELCROVOX equipment on this website
Elcrovox 1/3 voice encryptor
Elcrovox 1/4D narrow band voice and data terminal (STU-II compatible)
ELCROTEL was a series of encryption devices for teleprinter (telex) signals, generally using the 5-bit Baudot or ITA-2 standard, running at speeds between 45.45 baud and 1200 baud.

Known ELCROTEL devices
ELCROTEL equipment on this website
ELCROTEL 5 telegraphy encryptor
Abrufimpulsegenerator for ELCROTEL 4
ELCRODAT was a series of data and bulk encryptors, developed by Siemens for the AUTOKO data communications system, used by the German Army (Bundeswehr). Both ELCRODAT and AUTOKO were also used by the 2nd Danish Signal Battalion, to maintain contact with the German counter­part 610 GE SigBN in Rendsburg [3]. The name ELCRODAT is also used for a series of desktop phone and fax encryptors, currently available from Rohde & Schwarz.

Known ELCRODAT devices
ELCRODAT equipment on this website
Elcrodat 6-2 ISDN voice and data encryptor further developed by R&S
Elcrodat 4/1 CROSS FOX communication system, Signal Conversion Unit (SCU)
ELCROBIT is a series of data encryptors, initially developed by Siemens.

Known ELCROBIT devices
ELCROBIT equipment on this website
Elcrobit 96 data encryptor
Testdevice (Prüfgerät) for Elcrobit PGEb-96-2
ELCROMUX was a series of bulk encryption devices, also known as trunk encryption devices, initially developed by Siemens and ANT for data transmissions up to 2 Mbps.

Known ELCROMUX devices
  • ELCROMUX 1/1
    Bulk encryptor with optical interface
  • ELCROMUX 1/2
    Bulk encryptor with EUROCOM interface
  • ELCROMUX 1/3
    Bulk encryptor with CCITT interface
  1. Siemens AG, Encryption Equipments from Siemens
    Company brochure, 6 pages. 1991.

  2. Joachim Beckh, Blitz & Anker, Geschichte & Hintergründe, Volume 2
    ISBN 3-8334-2997-6. Date unknown.

  3. Jerry Proc's crypto pages, Elcro family
    Retrieved march 2018.
Further information
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© Crypto Museum. Created: Monday 26 March 2018. Last changed: Monday, 09 January 2023 - 11:08 CET.
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