Union Army Cipher Disk &ndash;Us Civil War Flag or Telegraph Encryption A precision laser engraved wood version of this famous cipher which was used for the encryption of messages of the Union Army during the American Civil War (1861-1865). It was a system primarily used for flag signals where there was a line of sight or for encrypted morse code messages. Note each disk has a unique serial number as was used in the original wheels. Instructions for use are included. The letters A.J.M on the disk are for Albert J Myer, the inventor and Chief Signal Officer of the Union Army. His system was called Flag Telegraphy or Wigwag. Made in USA by Creative Crafthouse