KY-57 (Vinson)
The KY-57/58 is a member of the VINSON family. The VINSON family consists of wideband secure voice (WBSV) units developed by the National Security Agency to provide line of sight half-duplex voice and data encryption at 16 Kbps. The KY-57/58 provides security for AM/FM, VHF, UHF, half-duplex PTT combat net radios and tactical wireline systems when used with the HYX-57. Also used by non-tactical users for high-level communications in  the local wideband telephone networks and wideband satellite terminals. The KY-57 is the manpack/vehicular model and the KY-58 is the airborne/shipborne version. The KY-57/58 is  certified to pass data up to TOP SECRET and accepts key from the family of Common Fill  Devices and also incorporates remote keying.

The VINSON equipment family which was fielded in the early 1980's as a replacement for the NESTOR family of crypto products.

KY-57 (top unit) shown with PRC-77 manpack radio.(Photo by Ralph Simpson)
There are also a number of radios which have been fielded with integrated VINSON encryption capability which do not require the use of an external KY-57, such as the SINCGARS  ICOM (Integrated Comsec) radio and the Harris Corp. PRC-117D and 117F radios.

The HYX-57 is used to connect a handset to the remote control unit for the KY-57 crypto unit.  It will encrypt voice and/or data (but not at the same time). It's a wideband device (16 Kbps) and can operate
directly with radios that are capable of handling the wideband encrypted signal.

KY-57/58 production was completed in 1993. No further production is planned.


This is a CMSC cable assembly for the KY-57 crypto unit and illustrates the way in which it is shipped from the manufacturer. Length: 6 ft. It connects J-3513 junction box to TSEC/HYP-57 vehicular Power Adapter then to the TSEC/KY-57. NSN part number  5995-01-130-1970 (Copy and photo via e-Bay)


Data Rate: 16 kpbs

Physical Characteristics
Height: 3 in.
Width:  5 in.
Depth:  6 in.
Weight: 4.9 lbs.

Battery: BA-1590 (Mercury), BA-5590 (Lithium Organic), BA-3590 (Alkaline), or
               BA-590 (Nickel Cadmium).

Power Input and Consumption:  28VDC;  3 Watts typical. Max. 4.4 Watts.

MTBF: 7,167 hours at 25°C ground mobile and 3,550 hours at 71°C ground mobile.

SUPPORTED BY:  In-Service-Engineering-Agent (ISEA), St. Julian's Creek.


CSESD-14G, July 1984. "Communications Security Equipment System Document for TSEC/KY-57/58". Confidential Document.
CSESD-31A, Dec. 1987. "Communications Security Equipment System Document for HYX-58/TSEC.

A set of five (1978 to 1985) U.S. Army technical manuals for TSEC/KY-57 (VINSON) communications security equipment (COMSEC) were originally issued for training and field use.  Each measures 4" X 5-1/2" and contains from 10 to 52 pages of text and illustrations.  They cover the secure and non-secure voice modes of operation as well as procedures for cryptographic zeroizing and keying this equipment.

TM 11-5810-256-OP-3: Operating Procedures for Communications Security Equipment TSEC/KY-57 in Wheeled Vehicles, 27 December 1978

TM 11-5810-256-OP-5: Operating Procedures for Communications Security Equipment TSEC/KY-57 Retransmission, 12 May 1983

TM 11-5810-256-OP-2: Operating Procedures for Communications Security Equipment TSEC/KY-57 in Manpack Operations, May 1984

TM 11-5810-256-OP-5: Operating Procedures for Communications Security Equipment TSEC/KY-57 in Wheeled Vehicles, 23 Aug. 1984

TM 11-5810-256-OP-4: Operating Procedures for Communications Security Equipment TSEC/KY-57 in Tracked Vehicles, 23 Aug. 1984

A VRC64S radio shown interconnected to KY-57 and powered by  a commercial power supply. (Photo source Brooke Clarke)

KY-57 technical manual circa 1984. (Photo via E-bay)
Front view
Top view. Inside there are 7 boards labeled:-E-DTH/1; E-DTG; E-DTF/1; E-DTD; E-DTC/1; E-DTB; E-DTA
Side view
Rear view
All photos in this table courtesy Potomac eScrap


1) US Navy Information Assurance web site:
3) Doug Eyre
4) Ralph Simpson <ralphenator(at)>
5) Potomac eScrap 571-292-5772

Back To Menu Page
Dec 2/12