Frank Gnegel of Germany provides this excellent description for the Codigraph.

"The Ideal Codigraph is a French enciphering machine built around 1909-1910. I had the opportunity to see one of these and to read a copy of the User's Instructions.

For those who have a Codigraph in their collection, I  must say that this machine is not a cryptographic device in the normal sense. Rather, the  purpose of the "enciphering " is not to encrypt plain text for secrecy but to save money on telegram transmission costs. The machine translates numbers into pronounceable words which are all 10 characters in length and also decodes them from letters back to numbers.

The development of the Codigraph was driven by the prevailing costs of sending a telegram at the beginning of the 20th century. Telegrams were sent in Morse code, but numbers were not sent as such. Each time a number was imbedded in a message, it was spelled out in full. Using the number  "38554"  as an example, thirty eight thousand five hundred fifty four is a lot of short words.

According to the tariff regulations of the "International Telegraph Union" [1] telegrams were charged  by the word which could consist up to 10 characters.  A word which had more than 10 characters was counted as two words. Under this pricing structure, it was very expensive to send a telegram so people were constantly searching for any opportunity to shorten the message. But the words in a telegram had to be composed of  pronounceable syllables in order to facilitate and to accelerate the work of the operators manning the Morse keys. That was also part of the regulations. Unpronounceable words or character strings such as  "WGHZKBDHSCX" were not allowed, otherwise the sender would be charged  for every single character as a new word.

The Codigraph was a solution for the part of the problem - sending numbers.  The machine transforms numbers into words of 10 characters each with pronounceable syllables. This is the reason why the apertures in the Codigraph normally show  two characters - a consonant and a vowel. The so-formed words can be pronounced by a human and be exactly  ten characters in length.

There is another reason as to why the Codigraph is not really an encipherment device. Every identical number is encoded identically each and every time. There is no means to change a "key" so any number encoded on one  machine can be easily decoded on any other machine".


From the copy which appeared on E-bay while this machine was up for auction.
"A rare Codigraph enciphering machine, French, 1910, signed on the cover: Ideal Codigraph, Charles Durand Inventor. Ste Address near Havre-France. All rights reserved Macon (S & L) July 29 1909. Washington D.C. Aug 13 1909 Class A XXc No 234.

On a plaque on the base board: Baveux Freres, St Nicholas d' Alieremont Seine Inferieure (France), serial number 1722. The rectangular wooden baseboard carrying a nickel cylinder canister with seven aperture sets arranged in two lines, the upper line of four sets has double letter combinations and all but two of the apertures have hinged covers two broken off marked in two sets 1-6, the lower line with three apertures showing numbers, the displays in the apertures are controlled by three knobs at each end, the central canister may be rotated to be clamped in place by a spring loaded arm locking into any one of an arc six holes worked in one end., with cylindrical metal cover, width approximately 33 cm., 13 in."

All Codigraph images Via E-bay.

Nameplate. (Photo by Ralph Simpson)


[1] An international organization founded in 1865 and still in existence today under the name of International Telecommunication Union.

Contributors and Credits:

1) Frank Gnegel <f.gnegel(at)>
2) Ralph Simpson <ralphenator(at)>

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Apr 27/12