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23-827: The DRSN provides multilevel secure voice and voice-conferencing capabilities to the National Command Authority (NCA, being the President and the Secretary of Defense of the United States), the Joint Chiefs of Staff , the National Military Command Center (NMCC), Combatant Commanders and their command centers, warfighters, other DoD agencies, government departments, and NATO allies. Department of Defense and federal government agencies can get access to

46-546: A numbering scheme similar to the North American Numbering Plan . The network had its own three-digit area codes for various geographic regions around the world. Each area code covered several three-digit exchange codes, usually corresponding to the central office telephone switches serving each installation. Thus, almost any telephone on a military base could be direct-dialed via AUTOVON. A selected set of telephones were four-wire AUTOVON phones, wired directly into

69-505: A single telephone instrument with which they can access both secure and non-secure networks. The DRSN carried around 15,000 calls per day prior to September 11, 2001 . DRSN usage subsequently peaked at 45,000 calls per day and by mid-2003 was running at around 25,000 calls per day. In that period the Defense Red Switch Network was expanded to support 18 additional US Federal Homeland Defense initiatives. Nowadays, this network

92-408: A special tone, if need be. For example, if a call was placed with Flash precedence and the route had no available trunks, the switch would preempt a Routine call, and if none in progress, would search for Priority and Immediate type calls. Only when all lines of a switch were already used with Flash or Flash Override precedence would the caller receive a reorder signal. The authority of a caller to use

115-441: A thin layer of insulation and a waterproof outer cover, DBC consists of multiple layers of heavy metallic-banded sheathing, reinforced by heavy rubber covers, shock absorbing gel, wrapped thread-fortified waterproof tape, and stiffened by a heavy metal core. DBC is preferable in some areas since it is more resistant to being the focus of lightning discharges. Most cable of this kind is coaxial or bundled fiber-optic cable. In

138-579: Is also called the Multilevel Secure Voice service. It's the core of the Global Secure Voice System (GSVS) during peacetime, crisis and time of conventional war, by hosting national-level conferencing and connectivity requirements and providing interoperability with both tactical and strategic communication networks. Multilevel precedence and preemption The Automatic Voice Network ( AUTOVON , military designation 490-L )

161-535: Is housed in such a way that it can absorb multiple blast waves propagating underground whilst still maintaining continuous operation. The engineering is still impressive by today's standards and it is still in use today. AUTOVON used a combination of its own constructed circuits and other lines operated by AT&T Corporation and smaller independent telephone companies , connected by high-speed switching centers produced by Automatic Electric Company to exchanges located far from other civilian or military targets. In

184-472: The 20th century much of it was filled cable . Direct-buried cable is cheaper and easier to lay than other kinds of cable that require protection from the earth. However, DBC is also easily cut during digging or other excavations. As a result, most direct-buried cable is found on side roads, not main thoroughfares. Some power cabling is also direct-buried. This kind of cabling must follow strict regulatory procedures regarding installation and backfilling. This

207-461: The AUTOVON network. Others could initiate AUTOVON calls with operator assistance. Though the numbering plan was similar to the U.S. civilian scheme, the routing structure was a very complex polygrid system unlike the civilian office classification scheme, which used a 5-level hierarchical system in which longer-distance traffic, in general, was handled by higher-level switches. It was barely within

230-508: The Autovon switch location map cited in External Links, below, for a snapshot listing of locations (some of the names in the map have been anonymized) and equipment manufacturer.) The AUTOVON system provided a facility for placing calls with multilevel precedence and preemption (MLPP). If in the public switched telephone network a caller encounters congestion because no circuits are available,

253-501: The US the cables were predominantly L-carrier coaxial multiplex built by AT&T, who also used them to carry about one third of all civilian long-distance calls, as their capacity was much higher than the military needed. Although unused, some of the cables remain today and the routes are visible on satellite photos. The system's traffic was transported over many media other than underground cable, including microwave links , open wire and, near

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276-442: The buttons in an additional column of the keypad, which produced the dual-tone multi-frequency (DTMF) signals A, B, C, and D: Routine was the level of calls without priority and required no special signaling; the user would only dial the telephone number. Calls with precedence required preceding the telephone number with the desired precedence signal. Calls of increasing precedence could preempt calls of lower priority, giving them

299-479: The cable repeater huts have been sold to private interests, to round out existing parcels, or as possible build-to-suit tower sites, etc. AT&T has been filling the small underground portion before sale, unless they sell to a major company. The junctions for AUTOVON are also being sold into private ownership, with a few exceptions. Most are stripped of all the equipment, although the AUTOVON junction in Mounds, Oklahoma

322-402: The caller typically receives the reorder tone ("fast-busy" signal) and is unable to reach the called party . In military networks such an event was not acceptable, as some calls must always be completed. AUTOVON included four message precedence levels: Routine , Priority , Immediate and Flash , and had an additional capability called Flash Override . These levels were activated using

345-463: The end of the system's life, fiber optic . Contrary to stories of underground concrete cable ducts, most of the cable was directly buried without added concrete, relying instead on the natural protection of soil. In some areas, however, cables from the AUTOSEVOCOM network were laid in parallel. These were often concrete-encased when the traffic they were carrying was not encrypted . Most of

368-575: The information processing capabilities of the Number Five Crossbar switching system which implemented it. The non-hierarchical routing structure was intended to get around any number of nodes destroyed in war. This system inspired similarly survivable ones for message networks, including in future decades the Internet . Local base switches would be connected to a few AUTOVON trunks, which the user would access by dialing 8 (or in some cases, 88) before

391-809: The network with approval of the Joint Staff. Upon approval by the Joint Staff, DISA will work with the customer and the appropriate military department to arrange the service. The Defense Red Switch Network consists of four major subsystems: the Switching Subsystem, the Transmission Subsystem, the Timing and Synchronization Subsystem, and the Network Management Subsystem. The Switching Subsystem uses both RED and BLACK switches to provide an integrated RED/BLACK service. End users are provided with

414-461: The original on 2022-01-22. Direct-buried cable Direct-buried cable ( DBC ) is a kind of communications or transmissions electrical cable which is especially designed to be buried under the ground without any other cover, sheath, or duct to protect it. Most direct-buried cable is built to specific tolerances to heat , moisture , conductivity , and soil acidity . Unlike standard telecommunications and power cables , which have only

437-625: The precedence levels was granted by complex regulations. Flash Override was not designated as a precedence level, but a capability designed to allow the President of the United States or other National Command Authority to preempt any other traffic in the network in an emergency. The International Telecommunication Union accepted the MLPP specification as recommendation Q.955.3 in March 1993. AUTOVON used

460-460: The telephone number. To dial locally a user would dial 9, and to dial using commercial long-distance, 1 (where this was supported). The United States Department of Defense (DoD) charged access to AUTOVON according to a complex billing system, and each base budgeted according to local practice. [REDACTED]  This article incorporates public domain material from Federal Standard 1037C . General Services Administration . Archived from

483-647: Was a major part of the Defense Communications System (DCS), providing non-secure switched voice services. The system was replaced in the early 1990s by the Defense Switched Network . The digitization of and upgrade of AUTOVON began in 1992 and took several years to complete. Equipment is housed in a network of redundant and distributed deep underground facilities spread across the globe, each of which are capable of withstanding multiple direct nuclear attacks of very significant yield. All equipment

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506-633: Was a worldwide American military telephone system. The system was built starting in 1963, based on the Army's existing Switch Communications Automated Network (SCAN) system. In June 1966, the Air Defense Command voice network was cut over to the new service. In 1969, AUTOVON switching centers opened in the United Kingdom , and later in other European countries, Asia , the Middle East , and Panama . It

529-536: Was sold with all the old equipment in place. The telephone switches used were initially a 4 wire version of Number Five Crossbar Switching System , replaced in the early 1970s after the more versatile 1ESS switch had shown its reliability. (Note that this paragraph disagrees in part with an earlier paragraph regarding the manufacturer of switching equipment. In general, switches in Bell operating territories were made by AT&T, and most others by Automatic Electric; see

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