The acronym means Automatic Secure Voice Communications.
AN/FTC-31 Autosevocom Telephone Switch (Photo courtesy Fort Monmouth Historical Office) 


During the mid 1960’s, the United States Government decided to implement a worldwide secure voice network. The US Army portion of this system was delegated to the US Army Strategic Communications Command (USASCC), Fort Huachuca, Arizona. A sub-command, namely the US Army 7th Signal Command , (headquartered at Fort Ritchie, Maryland) was responsible for all US Army Communications within the continental United States (CONUS). Every Army Fort or facility in the United States had a Post Signal Office, which was responsible for the operation of all telephone service, radio systems, communication center, etc .

It took several years to implement AUTOSEVOCOM-1 within the CONUS.  Numerous Signal Battalions in Vietnam also operated and maintained such facilities. In fact, many of these old Signal Battalions have  websites which can be located by searching for AUTOSEVOCOM using a search engine.

Equipment Comprising the AUTOSEVOCOM-1

TSEC/KY-1 -  Wideband (50kHz), half-duplex, secure voice cryptographic device enclosed in metal safe.

TSEC/HY-2, VOCODER -  converted voice analog into clear text digital stream.

TSEC/KG-13 - Key Generator; Mixed key with clear text digital stream and interfaced with a modem and conditioned line.

SECORD - (Secure Cord Board) - Manually operated, desk mounted patch panel. Its capacity was sixteen 50 kHz wideband lines,  sixteen 2400 narrowband user lines and 5 narrowband trunks.

AN/FTC-31 Automatic Telephone Switch -  For a community of KY-1 and narrowband subscribers.

RED Telephone Switches -  (At designated, totally secure,  classified locations) Telephones would be connected to the RED switch by shielded cables, enclosed in ferrous conduit.

Leased Modems and 3kHz conditioned lines within the CONUS.

Note:  The KY-1 and HY-2 were later replaced by the KY-3 and HY-11.

The original AUTOSEVOCOM-1 network consisted of:

-Narrowband Subscriber Terminals (NBST). A HY-2/KG-13 configuration would be installed and used within the post communications center.

-Wideband Subscriber Terminals (WBST). At large facilities, KY-1’s were used for local secure voice communications. KY-1’s were interconnected either by a manual SECORD or automatic telephone switch AN/FTC-31.

-Narrowband Trunking Unit (NBTU). A HY-2/KG-13 was hardwired into a SECORD, AN/FTC-31 or RED switch. These permitted subscribers to place long distance secure calls.
On a lighter note, each of the KY-1’s required a daily key card change at their remote locations. At many locations this involved a visit to the officers “boudoir” and required constant finesse to schedule. Some of the gray,  safe-mounted KY-1’s,  magically changed colour to better blend in with the prevailing décor.

Because of poor intelligibility, some officers refused to use the system.


The non-tactical AUTOSEVOCOM-1 network enabled users to discuss classified or sensitive information over the telephone. Difficulties with speech intelligibility, requirements for voice recognition, the holding of telephone conferences, speedier service, and simpler calling procedures led Defense officials to approve the development of an improved system —AUTOSEVOCOM II— and to designate the Army as the agency with the primary responsibility of developing the system. AUTOSEVOCOM II incorporated technological advances and furnished higher quality communications for the several thousand subscribers who were expected to use it when put into operation during the years 1980 to 1985. The U.S. Army Communications Command acted as program manager for AUTOSEVOCOM II.

The last SECORD/AUTOSEVOCOM Secure voice switch in the world was deactivated at the Pentagon in 1994 and that meant the end of the KY-3.

Devices which comprised the Autosevocom I system. (Graphic provided by George Mace) 

Autosevocom II block diagram. (Photo courtesy Fort Monmouth Historical Office) 

Credits: Autosevocom text provided by George Mace

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June 20/05