en|<a href="https://en.wikipedia.org/wiki/DRYAD_(Cryptography)" class="extiw" title="en:DRYAD (Cryptography)">DRYAD</a> sample cipher sheet. Cropped from Figure 20 in the on-line course "IS1100 Signal Operation Instructions (SOI) Edition A" issued by the U.S. Army Institute for Professional Development (AIPD), U.S. Army Training Support Center, Newport News, Virginia 23628-0001
<p>Vectorized version of <a href="//commons.wikimedia.org/wiki/File:KTV1400D.jpg" title="File:KTV1400D.jpg">KTV1400D.jpg</a>, originally downloaded from <a rel="nofollow" class="external free" href="https://hosta.atsc.eustis.army.mil/">https://hosta.atsc.eustis.army.mil/</a> cgi-bin/atdl.dll/accp/is1100/is1100_top.htm (this link no longer works).
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As a U.S. Government publication it is not copyrighted.
US gov
Unknown, probably no later than 1985
US gov