HY-2 VOCODER (Voice Coder)

Designed in 1961, this device was used for converting speech into a form compatible for encryption by a general purpose key generator  (ie KG-13) and transmission over a narrowband radio or telephone channel. It was a 16-channel, 2400-bps system using Flyball color-coded modular logic to reduce the weight to 100 pounds.The HY-2 was widely deployed in Vietnam but according to NSA web documents, President Johnson refused to use the HY-2 because of its poor "Donald Duck" sounding  quality. Its wide deployement is confirmed by its use in AUTOSEVOCOM I, a worldwide secure voice network used by the US government in the 1960's.
The  HY-2  was  the last generation of channel vocoder technology in the US.
This example of the HY-2 can be found in the National Cryptologic Museum. (Photo by  Doug Eyre)
Another view. (Photo by Vin Simmons)

Closeup of front panel. The meter face indicates it was made by Honeywell.  
Closeup of National Cryptologic placard.
Both images in this table are deratives from Ralph Simpson's photos. 

Credits and References :

1) Doug Eyre, Hewitt, TX
2) A History of Secure Voice Coding  http://www.nsa.gov/publications/publi00048.cfm
3) Vin Simmons  <vinsimmons(at)aol.com>
4) Ralph Simpson <ralphenator(at)gmail.com>

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Apr 1/12