Electronic Key Generator, TSEC/KG-27

The KG-27 was full duplex equipment used to encrypt tactical, multichannel communication. The unit was designed for simplicity of installation, operation, and maintenance. Within the Marine Corps, the KG-27 was used in the Terminal Set, Telephone, AN/TCC-72, which was the companion multiplexer van to the Radio Set, AN/GRC-201, and the Ground Mobile Forces (GMF) Super High Frequency (SHF) Satellite Communications Terminals, AN/TSC-85A/93A.

The KG-27 provided link security for low, medium, and high capacity Pulse Code Modulation (PCM) tactical radio relays of the Marine Amphibious Force (MAF). Since the KG-27 was a controlled telecommunication security item, it will be received through the Cryptographic Material System (CMS). It was the using units responsibility to "marry up" the KG-27 with the Terminal Set, AN/TCC-72, and the Satellite Communications Terminal, AN/TSC-85A/93A.

This KG-27 example is held by the National Cryptologic Museum. (Photo by Vin Simmons). Click on the image to see a larger image taken by Ralph Simpson.
Associated Equipment

The KG-27 had a requirement for associated auxiliary cables. The cables were not supplied withthe KG-27, but were supplied in kit form for installation in the appropriate communications system.


Access to keyed KG-27 equipment was granted to personnel whose duties required such access and who possessed an appropriate clearance. Access to unkeyed KG-27's and ancillary devices; associated testers, RGQ spares kits, and classified supporting documentation was granted to personnel whoseduties required such access and who possessed a confidential or higher clearance. Clearances were not required for external or cursory viewing of the KG-27. Military or civilian guards and security patrols that provided protection for locations where  unkeyed" KG-27's were installed (e.g., motor pools, flightlines, etc.) need not be cleared, but were instructed not to-handle the crypto equipment.


Classified keying equipment, and keyed KG-27's had to be stored as communication security (COMSEC) material of the appropriate classification in accordance with reference. Keyed KG-27's had to be under the continuous control of appropriately cleared personnel. Uninstalled KG-27's, classified supporting documents, and separate classified printed wiring assemblies  (PWA'S) were stored as confidential COMSEC material.

Physical dimensions:

Height: 7 in.
Width: 17.25 in.
Depth: 12 in.
Weight:   46 lbs

Unit cost: $3,950

Publications. Here are some publications that were available for the KG-27.

Short Title                               Long Title
KAO-133/TSEC               Operating Instructions, TSEC/KG-27

KAM-246( )/TSEC            Maintenance Manual, TSEC/KG-27

KAM-257( )/TSEC            Limited Maintenance Manual,  TSEC/KG-27

Source: Excerpts from Marine Corps Order 2200.2  ( LMC-l-dt) dated 30 Jan 1986.

Contributors and Credits:

1) Vin Simmons  <vinsimmons(at)>
2) Ralph Simpson <ralphenator(at)>


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