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Mixer machine - this page is a stub

The TP-845-A was a One-Time Tape (OTT) cipher machine, or mixer, built around 1970 by ACEC in Charleroi (Belgium) for use by the Belgian Army (ABL) 1 . The machine is based on the Vernam Cipher and was suitable for both online and offline encryption via analogue telephone lines as well as over radio. In the latter case it was often used in combination with the AN/GRC-9 radio.

The machine has the keyboard layout of a typical French typewriter — AZERTY rather than QWERTY — indicating that it was most likely used in a French-speaking country, such as France or the French-speaking part of Belgium (Wallonia).

Unlike other teleprinter-based cipher sytems like Hagelin and Philips — that use the common ITA2 code (Baudot-Murray) — the TP-845-A uses a multi-tone system, known as Coquelet-13 code [3]. This made the ACEC machine incompatible with other NATO systems. For communication with ITA2 systems, special interfaces were used.

The complete TP-845-A system, consists of the following items:

  • TP-B6-A Teleprinter (with built-in paper puncher)
  • CTS-A Cryptographic unit (with double paper-tape reader)
  • B6-A Power Supply Unit (PSU)
  • Canvas bag with cables and spare parts
  1. ABL = Armée Belge / Belgisch Leger (bi-lingual abbreviation).

This page is a stub
This cipher machine has recently been donated to Crypto Museum. In due course, it will be restored and eventually we hope to be able to describe the machine in more detail. If you have any information about this machine and its use, please contact us.

  1. Military Communications Museum (Belgium), Math Driessen (ON8PO)
    TP-845-A featured on this page, courtesy Math Driessen.

  2. TP-845-A service manual, Telecijferaaruitrusting TP-845-A (Dutch)
    Generale Staf van de Landmacht, Directie van de Transmissie, 1970.
    TM 11-2630-04-35-11

  3. Roland Prösch, Technical Handbook for Radio Monitoring
    Books on Demand, Germany, 2007.
    ISBN: 9783833490156

  4. Fraternele du 5e Batallion TTr et du 5e Gp CIS, Le téléimprimeur T-845-A
    Website. Retrieved February 2012.
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Crypto Museum. Created: Friday 02 July 2010. Last changed: Friday, 23 February 2018 - 20:57 CET.
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