The KY-3 is a secure telephone system developed by the U.S. National Security Agency

National Security Agency

The National Security Agency/Central Security Service is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S...

 in the early 1960s. The "TSEC" prefix to the model number indicates NSA's Telecommunications Security nomenclature system

Joint Electronics Type Designation System

The Joint Electronics Type Designation System , which was previously known as the Joint Army-Navy Nomenclature System and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Department during World War II for assigning an unclassified designator to...

. http://www.designation-systems.net/usmilav/miscsystems.html#_TSEC

According to information on display in 2002 at the NSA's National Cryptologic Museum

National Cryptologic Museum

The National Cryptologic Museum is an American museum of cryptologic history that is affiliated with the National Security Agency . The first public museum in the U.S. Intelligence Community, NCM is located in the former Colony Seven Motel, just two blocks from the NSA headquarters at Fort...

, the KY-3 provided high fidelity secure voice

Secure voice

Secure voice is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.-History:...

 over special wideband circuits known as called "4-wire dedicated drops". It was used by executives, diplomats, military leaders and the intelligence community. Some 2500 units were produced between 1965 and 1967 and it was one of the first security devices to use transistors packaged into functional modules. The unit was packaged in a large, grey relay rack cabinet. The KY-3 was replaced the STU-I

STU-I

The STU-I, like its successors sometimes known as a "stew phone", was a secure telephone developed by the U.S. National Security Agency for use by senior U.S. government officials in the 1970s.-External links:*-See also:*KY-3*Navajo I*STU-II...

 and STU-II

STU-II

The STU-II is a secure telephone developed by the U.S. National Security Agency. It permitted up to six users to have secure communications, on a time-shared basis. It was made by ITT Defense Communications, Nutley, New Jersey...

.

External links

• Delusion.org - National Cryptologic Museum pictures

See also

• STU-III
  STU-III
  STU-III is a family of secure telephones introduced in 1987 by the NSA for use by the United States government, its contractors, and its allies. STU-III desk units look much like typical office telephones, plug into a standard telephone wall jack and can make calls to any ordinary phone user...
  
  
• Secure Terminal Equipment
  Secure Terminal Equipment
  Secure Terminal Equipment is the U.S. Government's current , encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128k bits per second and are all digital...
  
  
• SCIP