G09C—CIPHERING OR DECIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY
G09C5/00—Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages
Dispositif d'enregistrement comportant des organes d'ecriture sur un support tournant, pour la transmission a distance d'informations ecrites par exemple