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Communications is the key to command.(1) It involves the transmission and reception of military instructions and information; it is at once the voice of command and the arm of control. It makes coordinated action possible by enabling our ships and aircraft to operate in a purposeful, cooperative effort. Modern naval operations can only be executed with effective communications and a master battle plan. All details of the plan must be communicated to the fighting units. Communications enables those at the highest echelons of command to test missions, objectives, and enemy capability and to determine appropriate courses of action. Naval telecommunications, being a function of command, must always be in a condition of preparedness. In the event of hostilities, the operating forces would depend on communications facilities in existence at the time.

A navy that operates on a worldwide scale requires the services of a global communications network. Commanders must be able to pass the word-to communicate-whenever necessary in any mode. They must be able to communicate between and among ships separated by varying distances and from and to ships, shore stations, and aircraft. The ability to communicate makes possible effective command and control. That, in turn, ensures the responsiveness of every mobile nerve center in the fleet to the tactical and strategic needs and services of every other element. A global organization of communications stations with hundreds of radio and landline circuits supports each force of ships. This support means a force of ships is never out of touch with its base of operations. Orders and information affecting the successful outcome of the force's mission are exchanged swiftly and accurately throughout every level of command. The direct result of reliable communications is a tightly directed fighting unit.

The Commander, Naval Telecommunications Command (COMNAVTELCOM), is designated the communications manager for Navy-assigned satellite systems. The responsibilities of the communications manager include operating the earth terminals and publishing Satellite Communications Operating Procedures (NTP-2).

Commander, Naval Space Command (COMNAVSPACECOM), is the operational manager for Navy satellites. The operational manager plans the location of spacecraft and fixed earth terminals and allocates satellite capacity, power, bandwidth, and operating frequencies.

The Navy uses two primary SATCOM systems. Long-haul (long-distance) communications takes place via the Defense Satellite Communications System (DSCS), which is managed by the Defense Information Systems Agency (DISA). This high-capacity global system uses satellites equally spaced around the world operating on superhigh frequencies (shy). Ships and stations located anywhere on the earth from 70 degrees north latitude to 70 degrees south latitude have access to one of these satellites. The Fleet Satellite Communications (FLTSATCOM) system operates at ultrahigh frequency (UHF), making possible the use of relatively low-cost terminals and simple antennas. Leased satellites (LEASAT) were also part of this system.

A typical operational link involves a satellite and two earth terminals. One station transmits to the satellite on a frequency called the up-link frequency. The satellite amplifies the signal, translates it to the down-link frequency, and then transmits it back to earth where the signal is picked up by the receiving terminal.

Fleet Broadcasts(2)

Radio traffic is sent to the fleet by two methods: broadcast and receipt. The first is a "do not answer" method; the second, as its name implies, requires a receipt from addressees for each message. The broadcast method allows the fleet to preserve radio silence, which is a great advantage from the standpoint of security.

Civilian and naval broadcasts have some similarity. Commercial stations in the broadcast band transmit programs to radio receivers in the homes in their communities. Likewise, Navy communications stations broadcast messages to fleet units in their particular geographic areas. The term broadcast, in fact, originated in naval communications.

The resemblance between Navy commercial stations ceases here, however. Information broadcast by naval communications stations is contained in chronologically numbered messages assigned to the ships. Fleet units copy the messages and check the numbers to ensure they have a complete file of all messages they should have received.

Automated systems now key fleet broadcasts. Messages are broadcast in their order of precedence. If the automated system receives a higher-precedence message while transmitting a lower-precedence message, it may interrupt the latter to transmit the higher-precedence message. All ships copy all messages addressed to them that appear on the broadcast schedule they are guarding.

Fleet broadcasts use satellites as their primary transmission media. High-frequency (HF) radio transmission provides broadcast services to ships that are unable to copy the satellite systems.

FLTSATCOM provides the primary means of Navy tactical satellite ship-shore-ship communications over the officer in tactical command information exchange subsystem (OTCIXS) and the tactical data exchange subsystem (TADIXS). The common user digital information exchange system (CUDIXS) and the naval modular automated communications system (NAVMACS) combine to form a general-service message traffic network.

Tactical Data Information Exchange System (TADIX B) Tactical Receive Equipment (TRE) subsystem receives, demodulates, decodes, decrypts, processes and distributes TADIXS B broadcast contact reports.

TRE and Related Applications (TRAP) Subsystem. This subsystem provides near real-time contact report data to a variety of AN/USQ-101(V Tactical Receive Equipment users.

Fleet Imagery Support Terminal (FIST) Subsystem. This subsystem transmits imagery from shore locations to ships, ship-to-shore locations, ship-to-ship, or shore-to-shore.

The installation of subsystem baseband equipment and RF terminals aboard ships and aircraft is driven by communications traffic levels, types of communications and operational missions. For example, OTCIXS RF links carry teletypewriter traffic and data-link communications for tactical operations. Fleet Broadcast, being a common denominator in Naval communications, is received by many different types of ships. A typical suite on a large ship may include Fleet Broadcast, CUDIXS/NAVMACS, Secure Voice, TADIXS/OTCIXS, Teletypewriter, and TACINTEL equipment.

The following subsystems comprise the Navy UHF SATCOM System:

Fleet Satellite Broadcast Subsystem;

Common User Digital Information Exchange Subsystem (CUDIXS)/Naval Modular Automated Communications Subsystem (NAVMACS);

Submarine Satellite Information Exchange Subsystem (SSIXS);

Special Intelligence SSIXS (SI SSIXS) Subsystem;

Secure Voice Subsystem;

Tactical Intelligence (TACINTEL) Subsystem:

Teletypewriter Subsystem:

Tactical Data Information Exchange Subsystem (TADIXS)/Officer In Tactical Command Information Exchange Subsystem (OTCIXS):

Demand Assigned Multiple Access (DAMA) Subsystem:

Tactical Data Information Exchange Subsystem Broadcast B (TADIX B);

Tactical Receive Equipment (TEE);

These subsystems, with exception of the Teletypewriter, Secure Voice, and Control subsystems, apply some form of automated control to the communications being transmitted. This control is structured to include message or data-link processing before and after transmission as well as control of the RF network (link control) through which the communications are taking place. The automation of these functions and the actual message or data-link transmissions are under the control of a processor. With the advent of Communication Support System, the users will be permitted to share total media capacity, on a priority demand basis in accordance with Communication Plans.


The Fleet Satellite Broadcast Subsystem transmits Fleet Satellite Broadcast message traffic in a high-level jamming environment. The subsystem has 15 subchannels of encrypted message traffic at an input data rate of 75 bps per channel. These subchannels are time-division multiplexed and transmitted in a one-way RF transmission at 1200 bps. The shore-based terminal (NCTAMS/NCTS) transmits these data on a direct sequence spread-spectrum SHF signal to the UHF satellites, where the signal is translated to UHF and down-linked to the subscribers. The High Speed Fleet Broadcast (HSFB), planned for the mid-1990's, will upgrade the Fleet Satellite Broadcast Subsystem.

The Fleet Satellite Broadcast message traffic is queued and/or channel selected prior to transmission by two processor-controlled message switching systems. These systems are the Naval Communications Processing and Routing System (NAVCOMPARS), for general-service message traffic, and STREAMLINER, for special-intelligence message traffic. Fleet weather data from Naval Oceanographic Command Centers are also transmitted on non-processor controlled channels of the Fleet Satellite Broadcast.

General-service message traffic can be read into the NAVCOMPARS processor by over-the-counter facilities at the NCTAMS/NCTS or can be input automatically to the processor when the message traffic is sent from an Automatic Digital Information Network (AUTODIN) switching center. Generally, the same process is applicable for entering special intelligence messages via STREAMLINER. Fleet weather data are input directly to the system by teletypewriter or a recorder-reproducer.

The queued and/or channelized message traffic from these three collection points for Fleet Satellite Broadcast transmission is encrypted and input to a time-division multiplexer, where it becomes a 1200-bps data stream and is passed to the transmitter. The structure of the Fleet Satellite Broadcast transmission allows 15 subchannels: eleven 75-bps subchannels for general-service message traffic, two 75-bps subchannels for special-intelligence message traffic, and two 75-bps subchannels for Fleet weather data. A sixteenth subchannel in the Fleet Satellite Broadcast transmission is used for frame synchronization.

When the Fleet Satellite Broadcast transmission is made via FLTSATCOM channel 1, the time division multiplexer output will be patched to the Satellite Communication Terminal AN/FSC-79. Use of FLTSATCOM channel 2 requires connection of multiplexer output to the UHF Transceiver AN/WSC-5(V) as the UHF backup mode.

Since two satellite channels are available for Fleet Satellite Broadcast message traffic and several different RF modulation techniques are defined for the up-link transmission, there are seven different modes in which this RF link can be transmitted. In modes 1-6, the SHF transmissions are made by the Satellite Communication Terminal AN/FSC-79. Mode 7, which operates the RF up-link and down-link at UHF, uses the UHF Transceiver AN/WSC-5(V). It should be noted that whether the AN/FSC-79 or the AN/WSC-5(V) transmitter is used, there is no change to data format or data rate.

The subscribers receive the UHF down-link signal, which the AN/SSR-1 or 1A receiver system demodulates and demultiplexes. The demultiplexed output data stream from the receiver is decrypted and read into the Naval Modular Automated Communication System (NAVMACS) and Tactical Intelligence (TACINTEL) processors for message Wing and printing. After decryption, weather data are sent Indirectly to teletypewriters. All subscribers are re/ Hired to guard selected Fleet Satellite Broadcast f subchannels. NAVMACS and TACINTEL equipped F ships will normally screen the broadcast through the appropriate automated system(s). However, ships not equipped with one or both of these automated systems will normally output the broadcast subchannels to teletypewriters. At selected shore stations, the Fleet Broadcast message traffic is retransmitted on HF links. These stations receive the time-division multiplexed data stream directly via cable or satellite.

There are five locations from which the message traffic can be transmitted by the Fleet Satellite Broadcast Subsystem. All five locations (see table below) have the capability to transmit these data via the AN/FSC-79 SHF terminal or the AN/WSC-5(V) UHF terminal. With the exception of NCTAMS MED, these same stations can also transmit the Fleet Satellite Broadcast message traffic via HF facilities.

NCTAMS LANT Norfolk, Virginia AN/WSC-5(V)

Northwest, Virginia AN/FSC-79

NCTAMS MED Bagnoli, ltaly AN/WSC-5(V)

Lago Di Patna, Italy AN/FSC-79

NCTAMS WESTPAC Finegayan, Guam AN/WSC-5(V)


NCTAMS EASTPAC Wahiawa, Hawaii AN/WSC-5(V)


NCTS, Stockton Stockton, California AN/WSC-5(V)


Subscriber installations of the AN/SSR-1A Receiver System are located on ships and in AN/TSC-96(V) Marine Corps RF shelters.

The AN/SSR-1 or AN/SSR-1A receiver system is also installed at some NCTSs to receive Fleet Broadcast traffic, which is subsequently retransmitted from there on HF links. NCTSs with retransmitting (i.e., rekeying) facilities are in the following locations: Greece, Australia, Spain, Japan, United Kingdom, Philippines, Puerto Rico, USA (Adak, San Diego), and Iceland.

Fleet Satellite Broadcast message traffic is transmitted via satellites positioned in synchronous orbit over CONUS and the Atlantic, Pacific, and Indian Oceans. Simultaneously, the Fleet Broadcast message traffic may be rebroadcast on existing HF links. NAVCOMPARS compiles and queues this message traffic prior to transmission.

As FLTSATCOM satellites were inserted into orbit, the Fleet Satellite Broadcast message traffic was switched over from transmission via Gapfiller satellites to transmission via the FLTSATCOM satellites. In this satellite switchover, the AN/FSC-79 transmitter was used. The major differences in Fleet Satellite Broadcast operation are in the RF transmission frequencies, the effective isotropic radiated power of the transmitter, and the up-link RF signal modulation. The rebroadcast of message traffic via HF links continues with the use of FLTSATCOM satellites. In switching the Fleet Satellite Broadcast operations from Gapfiller to FLTSATCOM satellites, there were no changes to the RF equipment other than switching (patching) actions. LEASAT satellites are operational with Fleet Satellite Broadcast using the same up-link and down-link equipment, resulting in no change other than in the satellites used.

The High Speed Fleet Broadcast (HSFB) Program is planned to upgrade the Fleet Broadcast System (FBS) transmission subsystem by improving broadcast transmission speed, information throughput, and resource flexibility. The HSFB upgrade offers the capability to reallocate available information throughput capacity among users in response to changing tactical environments and the ability to handle the traffic quantity and quality demands imposed by high speed automated subsystems. The HSFB design will provide hardware improvements to the satellite and HF segments of the transmission subsystem and incorporates the necessary, related software improvements to message processing systems both ashore and afloat.



The Common User Digital Information Exchange Subsystem (CUDIXS) is a shore-based installation of processors and peripheral equipment that provides RF link control of the network and processing of message traffic at shore installations. The Naval Modular Automated Communications Subsystem (NAVMACS) has similar equipment at subscriber terminals: it follows the CUDIXS link-control protocol and processes message traffic at those locations. The NAVMACS program has been phased to address the growth capability in existing installations and the unique requirements of ships having a high volume of message traffic. In ships that have a message processing and distribution system (ADDS), the NAVMACS processor is interactive with the MPDS processor.

Collectively, CUDIXS/NAVMACS provides improved ship-to-shore and shore-to-ship operational communications. These improvements are directed toward increased message traffic throughput rates, increased traffic volume, and improved link reliability. It is a functional replacement for the ship-to-shore itinerant ORESTES nets.

The design addresses the need of high-volume subscribers (special users) having a requirement for two-way message traffic flow on the CUDIXS link and those subscribers (primary users) with a one-way (ship-to-shore) requirement for message traffic flow on the same link. (The primary users receive their shore-to-ship message traffic via Fleet Broadcast.) The structure of CUDIXS link control previously supplied a network membership of 50 primary users and 10 special users within each network. This has now been changed to permit all users to send and receive traffic. Two CUDIXS/NAVMACS networks are normally used in each satellite footprint.

At shore facilities, the primary collection point for message traffic to be transmitted or received on the CUDIXS/NAVMACS RF link is the NAVCOMPARS. Message traffic for transmission on the CUDIXS link (special users) can be input to NAVCOMPARS by over-the-counter facilities at the NCTAMS/NCTS. Message traffic originating at other locations is passed directly to the NAVCOMPARS processor via AUTODIN automatic switching centers.

Incoming message traffic originating at both the primary and special subscribers is passed from the CUDIXS processor to NAVCOMPARS Depending upon message routing, the traffic may be distributed at that point or passed by NAVCOMPARS to the AUTODIN automatic switching center.

Each active or inactive subscriber to a CUDIXS net has an identification number that is recognized by the CUDIXS and NAVMACS. When a unit is considered a special subscriber that has a requirement for two-way message traffic flow, the CUDIXS operator can assign an identification number from 1 to 60 for that subscriber. A unit that is considered a primary subscriber with a requirement for only ship-to-shore traffic flow is assigned a number from 11 to 60 by the CUDIXS operator.

These identification numbers serve many purposes, one of which is the screening of incoming message traffic at the subscriber terminal. Where more than one special subscriber is active in the network, the subscriber processor passes to the peripheral equipment only that message traffic with the unit identification number assigned by the CUDIXS operator. The remaining message traffic in the transmission cycle is discarded. A NAVMACS processor installation is required to screen CUDIXS message traffic and up to four subchannels of Fleet Broadcast message traffic.

Message traffic received by NAVMACS shipboard installations is normally output to peripheral equipment (printer). Five ships have a Communication Data Processing System (CAPS) installed. Ships with CDPS installations perform message screening within these systems and not in NAVMACS.


SSIXS is designed to complement terrestrial VLF and Medium Frequency/High Frequency (MF/ HF) communication links between shore-based submarine Broadcast Control Authorities (BCAs) and submarines. The subsystem provides the submarine commander with the capability to receive messages transmitted via the satellite at scheduled intervals ("Group Broadcasts"). Between Group Broadcasts, submarines may transmit messages to the BCA, including a request for messages held in queue. The shore terminal responds to these transmissions with acknowledgments for the individual messages just received and transmits all messages held that are addressed to the queuing submarine. The availability of the two modes of operation, Group Broadcast and Query/Response, permits the choice of whether to be active or passive at the discretion of the submarine commander. One 25-kHz wideband channel on each of the four FLTSATCOM satellites is allotted to SSDCS.

A single SSIXS network may have up to 120 submarine subscribers. A single network may be established on more than one satellite (e.g. when the operating area under the cognizance of a BCA extends beyond the footprint of a single satellite), or two BCAs may share a single satellite channel by offsetting the time of their respective Group Broadcast transmissions.

The SSIXS baseband equipment installed at the BCA locations ashore perform a dual function. It accepts messages for delivery to submarines via either satellite or VLF paths, and receives messages from submarines via the satellite path for onward delivery. It also provides the shore SSIXS operator with the capability to compose and control the VLF VERDIN broadcasts by an interface with the Integrated Submarine Automated Broadcast Processing System (ISABPS). The SSIXS subscriber terminals afloat perform the complementary operations necessary to permit reception of Group Broadcasts or conduct a Query/ Response episode.

At the BCA, messages addressed to submarines (that have been received from AUTODIN, NAVCOMPARS, or locally over-the-counter in the Message Center) are entered into the SSIXS shore terminal by using the operator console keyboard, the high-speed paper tape reader, or the Submarine Message Automated Routing Terminal (SMART). Aboard the submarine, the message traffic is input via the teletypewriter or tape reader equipment. SSN submarines that have the Data Link Control System (DLCS) installed have an additional input/output capability via the Sensor Interface Unit (SIU) for over-the-horizon targeting (OTH-T) messages. (OTH-T messages are segregated in SSIXS by the presence of a unique two-character (OH) message indicator code in the SSIXS message format.)

Ashore, the SSIXS subsystem shares access to the same satellite RF terminal equipment at the NCTAMS as the other UHF SATCOM subsystems, with the exception of COMSUBGRU SEVEN, Yokosuka Japan, which is equipped with dedicated AN/WSC-3 transceivers. Since each BCA is located some distance away from the NCTAMS, line modems and land lines are required for interconnection. The submarine UHF RF terminal is the single-channel, half-duplex AN/WSC-3. SSIXS transmissions are at the 4800 bps rate. The capability to operate SSIXS in a DAMA net has been successfully demonstrated and will be employed in the future.

Each subscriber to a SSIXS network is assigned a unique identification number which is used in all transmissions to or from the subscriber. The identification numbers are stored within the shore station and subscriber processors. The application of these numbers takes many forms.

At the shore stations, the subscriber identification number, when combined with broadcasts, will determine the number of times message traffic is transmitted to a subscriber. In the event a subscriber chooses to make a transmission to the shore station, this identification number will be included in the transmission. If the number is not included, the shore station will not acknowledge the transmission.

The identification number is used at subscriber terminals to screen broadcast transmissions for message traffic directed to the subscriber. The remaining data in the transmission are discarded. In the link-control protocol employed by SSIXS, the broadcast of message traffic does not require an acknowledgment by the receiving subscribers. When a transmission is made by a subscriber to the shore station, the shore station transmits an acknowledgment of the subscriber transmission. The acknowledgment occurs at the beginning of the transmission and is not an integral part of an individual data block transfer.


In addition to the General Service (GENSER) SSIXS subsystems, an additional SSIXS capability dedicated to Special Intelligence (SI) communications and designated SI SSIXS, has been installed at all five BCAs. SI SSIXS is functionally similar to GENSER SSIXS. The SI SSIXS capability provides privacy among subscribers through the use of unique ID numbers.

SSIXS subscriber terminals are installed in SSBN and SSN type submarines.

The shore terminal installations are:

Organization Location

Submarine Group 7 Yokosuka, Japan

Submarine Group 8 Agnano, Italy

Submarine Group 10 Kings Bay, Georgia

SUBPAC Pearl Harbor, Hawaii

SUBLANT Norfolk, Virginia


The Secure Voice subsystem enables, via satellite relay, the transmission of ship-to-ship, ship-to-shore, and shore-to-ship voice communications. Ship-to-Shore voice communications beyond the immediate area of the NCTAMS/NCTS are provided by AUTOSEVOCOM extension. The subsystem transmits and/or receives secure;voice communications via a half-duplex, push-to-talk satellite link Channels on each of the four FLTSATCOM satellites have been allocated for use by the Secure Voice subsystem. Control of the voice channels is maintained by the Secure Voice controller (operator) at the responsible NCTAMS/NCTS within a satellite footprint.

The subsystem employs digitized voice at a data rate low enough to be compatible with a 3-kHz voice channel and, therefore, is considered narrowband. This requires special analog-to-digital processing of the speech signal at the handset terminal. The RF transmission data rate is 2400 bps. The Secure Voice subsystem has dedicated RF channels on the UHF, SATCOM satellites as well as dedicated DAMA slots where DAMA nets have been established.

The RF terminal installations on mobile platforms determine the manner in which a Secure Voice transmission is made. These mobile platforms may be categorized into two types.

The small ship/submarine, in which a single channel AN/WSC-3(V) UHF transceiver and TSEC/KS36 cryptographic equipment are shared between NAVMACS or SSIXS baseband equipment and a Secure Voice terminal. The larger ships in which two or more AN/ WSC-3(V) UHF transceivers and cryptographic equipment are installed. This type of installation normally has a transceiver dedicated for Secure Voice transmission.

Use of the Secure Voice RF channels can be obtained by either of two methods. In the first method, all mobile platforms access a Secure Voice channel if the channel is not in use. In this operation the mobile platform contacts another mobile platform directly by using one of the voice channels available. When coordination of the voice communication with shore commands is required, the mobile platform contacts (via a voice channel) the voice controller who, in turn, alerts the recipient(s) of an incoming voice transmission.

The second method of securing a voice channel requires a totally different process and is used if the channels are busy or procedures require such an operation. For the small ship or submarine, the voice transmission requires that a voice transmission request be sent by message to the Secure Voice controller. The small ship uses an operator-to-operator type message via the CUDBS/NAVMACS RF network. The submarine may transmit a voice channel request during a random-access time period in the SSIXS net cycle. In both instances the voice transmission request is passed from the reception point at shore to the voice controller. The CUDBS baseband equipment and operator are located in the same building (NCTAMS/NCTS) with the Secure Voice Controller. The Secure Voice controller coordinates the voice transmission (i.e., contacts the voice transmission termination points, assigns a voice channel, etc.).

Secure Voice installations have been completed at the following locations and shipboard terminals. The Secure Voice terminals installed at NCTAMSs/ NCTSs have the capability to simultaneously control voice transmissions on four satellite RF channels.

NCTAMS LANT Norfolk, Virginia

NCTAMS MED Bagnoli, Italy

NCTAMS WESTPAC Finegayan, Guam

NCTAMS EASIPAC Wahiawa, Hawaii

NTCS, Stockton Stockton, California

NCTS, Diego Garcia Diego Garcia

CINCUSNAVEUR London, United Kingdom

CNO Washington, DC


Marine Corps Satellite Communications Central AN/TSC-96(V)


The Radio Wireline Interface (RWI) has been developed to access and interconnect existing and future secure voice communications subsystems and equipments. Naval Secure Voice Subsystems incorporate major terrestrial (wireline), SATCOM (both UHF and SHF), and HF secure communications links. The RWI is an integrator of those systems, developed primarily to alleviate limitations of existing Fleet Secure Voice Links and provide interoperability of existing and planned subsystems and equipments.

The RWI provides the capability to connect the shore-based worldwide wireline systems with the SATCOM, Defense Satellite Communications Systems (DSCS), and alternate HF systems. The system effectively extends shore communications seaward and provides the same secure voice telephone communications to commands at sea that are currently provided to the worldwide shore establishment.

With the exception of the PAU for the STU-III, all PAUs are designed to a common configuration. Mechanically, ah units are contained in the same type of enclosures, with varied front and rear connector panels. All unit designs incorporate the same type of card cages, header panels, etc. The major differences among the units involve circuit card complement and backplane wiring. Each port applique unit contains from 12 to 18 circuit cards. Common type circuit cards are those which provide common functions in some or all PAUs. Unique circuit cards provide a particular function, unique to the associated peripheral.

Operator control of the RWI involves operator access of any communication through selected channels and interconnection of these channels. Operations primarily involve monitoring and connecting functions. The console functions in conjunction with the RDM and the operator/monitor port applique. The operator communications are channeled through matrix ports in the same manner as other communications. Control signals, developed and initiated at the console, command solid-state switching circuits in the RDM which connect or disconnect selected channel PAUs. Corresponding status and dynamic signals are projected over the port status line and dynamic display bus through respective lamp display circuits to indicators at console panel.


The TACINTEL subsystem is used for transmission of special-intelligence communications. The subsystem is essentially a computerized message processing installation that makes it possible to transmit and receive message traffic via satellite in a controlled environment. The link-control protocol for TACINTEL has been adapted to a format required for communication across a DAMA-supported channel. A polling scheme is used that can support a net membership of 23 subscribers within a satellite footprint. A portion of a DAMA 25-Khz channel on each of the FLTSATCOM satellites has been allocated for TACINTEL. At subscriber terminals, the baseband equipment is used for handling TACINTEL message traffic as well as for screening two subchannels of Fleet Broadcast transmissions.

TACINTEL also processes time-sensitive sensor and other data essential to Indications and Warning and OTH-Targeting. This data is not in narrative message format, and is afforded priority in the system. In addition, the system, unlike CUDIXS/NAVMACS, is capable of direct ship-to-ship interchanges of this data, but not of narrative record messages. Afloat and ashore, this data is fed to other baseband equipment and processors.

At both shore facilities and subscriber terminals, message traffic may be entered via the TACINTEL peripheral equipment such as the tape reader (not applicable to shore) or the display terminal keyboard. Most of the message traffic is entered automatically by systems or facilities connected to TACINTEL at those locations.

TACINTEL baseband equipment uses an RF terminal in common with other subsystems at both the shore facilities and subscriber installations. The RF terminal at shore locations is an UHF Transceiver AN/WSC-5(V). At the subscriber installations, the UHF transceiver is an AN/GSC-3(V). The TACINTEL RF channel operates as a half-duplex UHF link, which can be operated at a transmission rate of 4800 Ups, 2400 bps, or 1200 Ups. The modulation of the RF signal is differentially encoded phase-shift keying (DESK).

The TACINTEL suite shore site installations are in Naval Security Group (NSG) spaces.

Naval Security Group Activity Northwest, Virginia

Naval Security Group Activity Agnano, Italy

NCTAMS WESTPAC Finegayan, Guam

NCTAMS EASTPAC Wahiawa, Hawaii

Naval Security Group Activity Skaggs Island, California

Naval Security Group Activity Edzell, Scotland

TACINTEL Shipboard Installations include: AGF, BB, CG, CGN, CV, CVN, DD, DDG, LCC, LHA, LHD, LPD (Flag), and LPH.



The Tactical Data Information Exchange Subsystem (TADIXS) is designed to support the exchange of Over-The-Horizon Targeting (OTH-T) information between shore and fleet-based computer systems (collectively referred to as Tactical Data Processors (TDPs)) which support Navy cruise missile operations.

Implementation of OTH-T data communication via TADIXS has been accomplished in four distinct phases, ranging from a manual, contention-based network to a fully automated worldwide system with independent TADIXS and Officer in Tactical Command Information Exchange Subsystem (OTCIXS) networks in each satellite coverage area. In Phase I, OTH-T communications were initially accomplished by the manually intensive Outlaw Shark Digital Interface Unit (OSDIU) at shore and afloat units. Shore users time-shared radio assets via a Digital Sharing Device (DSD) located at the supporting Naval Computer and Telecommunications Area Master Station (NCTAMS). In Phase II, the Interconnecting Group ON-143(V)61USQ replaced the OSDIU as the link control device. The OTCIXS satellite network was introduced to provide a two-way satellite link to support inter- and intra-Battle Group communications. In Phase II, OTCIXS was also used for OTH-T communications support between shore and afloat units.

TADIXS Phase III is characterized by a complex DSD/ON-143(V)61USQ shore configuration, the addition of a second ON-143(V)6/USQ for afloat platforms, and the introduction of a new shore-to-ship tactical circuit, TADIXS, to support OTH-T communications. The OTCIXS satellite network continues to provide inter and intra-Battle Group communications and is now designated as the return path for ship-to-shore OTH-T communications.

In 1991 TADIXS Phase IV provided integrated worldwide connectivity among the OTH-T community, using both dedicated connectivity and satellite links, through a series of computer-controlled switching nodes called TADIXS Gateway Facilities (TGFs) (figure 23). The shore user systems will have dedicated connectivity with the TGFs, which shall be located at the four NCTAMS at Norfolk, Virginia; Bagnoli, Italy; Wahiawa, Hawaii; and Finegayan, Guam; and at the Naval Computing and Telecommunications Station (NCTS) in Stockton, California. The TGFs interface with Gapfiller, FLTSATCOM, or LEASAT links and provide routing control within their respective coverage areas. The TGFs provide shore user access and routing to/from both the TADIXS and OTGIXS satellite networks. The TGF is the source of a shore-to-ship broadcast of OTH-T data, via the TADIXS satellite network, to cruise missile equipped ships and submarines As in TADIXS Phase III, the OTCIXS satellite network continues to provide inter- and intra-Battle Group communications and ship-to-shore OTH-T communications. The afloat platforms continue to use the same equipment suites available during Phase III.

The shore-based TDP facilities which employ services provided by TADIXS include: Fleet Ocean Surveillance Information Centers (FOSICs) or Facilities (FOSIFs), Submarine Operating Authority (SUBOPAUTH) Shore Targeting Terminals (STTs), Cruise Missile Support Activities (CMSAs), and the Joint Operational Tactical System (JOTS). The Washington Planning Center (WPC) serves as an operational backup for the CMSAs and as the test and evaluation facility for the Mission Data Distribution System (MODS), and the CMSA TDP system. COMASWFORTHIRDFLT, located in Hawaii, uses the Tactical Data Display System (TADS), the TDP system upon which the STT is based, for Research and Development purposes. The FOSICs/ FOSIFs use the Ocean Surveillance Information System (OSIS) as their TDP. Each shore site will be provided with a Tactical Data Processor Controller (TDPCON) for connectivity with the local TGF. The local TGF will perform routing services and provide satellite access to TADIXS and OTCIXS. In TADIXS, the FOSICs/FOSIFs, STTs, CMSAs, and JOTSs primarily operate in a transmit mode, broadcasting data to fleet users. In OTCIXS, the FOSICs/FOSIFs, STTs, CMSAs, and JOTSs primarily operate in a receive-only mode to accept command/control and surveillance information from afloat TDP systems for track correlation and generation purposes.

The TADIXS Phase IV shore configuration comprises four programs: the TADIXS Gateway Processor (TGP), Remote Controller (REMCON), Radio Controller (RADCON), and the TDPCON. The TGP and REMCON programs are both hosted in separate AN/UYK-44(V) data processing sets. The RADCON and TDPCON programs are hosted in separate ON-143(V)6/USQ interconnecting groups. The TDPCON is located at the TDP site. The TGF, located at the NCTAMS or NTCS, Stockton, consists of the TGP, REMCON, RADCON, and associated equipment. Each TGF will be capable of accessing up to eight satellite links within two satellite coverage areas that include that TGF. These accesses may involve any combination of TADIXS and OTCIXS RF networks.

Shore TADIXS/OTCIXS TDP Installations





WPC Washington, DC


FOSIF ROTA Rota, Spain



FOSIF WESTPAC Kamiseya, Japan


JOTS CINCPACFLT Pearl Harbor, Hawaii



NOIC Suitland, Maryland

Afloat platforms use one of three types of TDPs. The Tactical Flag Command Center (TFCC) uses the Flag Data Display System (FDDS) as a TDP to process and display OTH-T data required by the Officer in Tactical Command (OTC) to manage a tactical environment. Surface ships equipped with cruise missiles use the TOMAHAWK Weapon Control System (TWCS) as a TDP to support receipt of OTH-T data needed to direct a cruise missile. Cruise missile equipped submarines employ the Combat Control System (CCS) MK1, which is interfaced to the OTCIXS ON-143(V)6/USQ via the Sensor Interface Unit (SIU) J-3780/UYK

The TADIXS and OTCIXS surface ship and submarine programs are hosted in an ON-143(V)6/USQ satellite link controller. The ON-143(V)6/USQ provides automatic crypto synchronization, store and forward of incoming and outgoing teletypewriter and TDP traffic, and control of the satellite link access. The ON-143(V)6/USQ interfaces with an AN/WSC-3(V) UHF satellite transceiver (via a TD-1271B/U DAMA unit, as required), a KG-36 or KG-84A crypto device (depending on the satellite network), another ON-143(V)6/ USQ (if installed), and various types of TDP systems.

Operationally, surface ship and submarine platforms operate in a TADIXS receive only mode.


The UHF Demand Assigned Multiple Access (DAMA) subsystem was developed to multiplex several baseband subsystems, or users,, on on 25 kHz satellite channel. This has the effect of adding more satellite circuits per channel to the UHF Satellite Communications system. Without UHF DAMA, each satellite communications subsystem requires a separate satellite channel. For DAMA operations, a single master control station is active within each satellite footprint.

Follow-on programs are developing additional DAMA multiplexers and implementing DAMA control and management tools.

Mini-DAMA (AN/USC-42) integrates the TD-1271 multiplexer and AN/VVSC-5 transceiver functions into a single system, significantly reducing the DAMA system's overall size and weight. Two versions are being developed: one for ship, submarine and shore facilities, the AN/USCZ2(V)1; and one for air platforms, the AN/USC42(V)3. Mini-DAMA will also provide additional UHF communications modes, such as interoperable 5 kHz Air Force TDMA, 5 kHz Navy Non-TDMA and UHF line-of-sight communications.

As more DAMA multiplexers are developed and fielded, more 25 kHz UHF SATCOM channels will use DAMA. To effectively manage the increasing number of DAMA recourses, a DAMA controller is being developed and fielded in phases. The first phase, the DAMA Semi-Automatic Controller (SAC), uses the TD-1271's semi-automatic mode to allocate and control DAMA resources. With the fielding of Mini-DAMAs, the controllers will also be upgraded to implement a fully automatic DAMA controller (Auto-DAMA), which supports the CSS and Copernicus architectures.



The AN/USQ-101(V) Tactical Data Information Exchange Subsystem Broadcast (TADIXS B) Tactical Receive Equipment (TRE) System receives, demodulates- decodes, decrypts, processes, and distributes TADIXS B broadcast contact reports. There are seven versions of TRE: AN/USQ-101(V)1 U.S. Army TRE; AN/USQ-101(V)2 Single Channel US Air Force TRE; AN/USQ-101(V)3 US Navy Surface Ship TRE; AN/USQ-101(V)4 US Navy Submarine TRE; AN/USQ-101(V)5 US Marine Corps Team Transportable TRE; AN/USQ-101(V)6 US Navy Shore TRE; and AN/USQ-101(V)7 Dual Channel US Air Force TRE.

Each of the configurations output the TADIXS B contact reports to either Tactical Data Processors (TDPs), display terminals, or other systems The existing or proposed TDP Systems, display terminals, and systems receiving TRE contact reports include: Navy Tactical Data System (NTDS); Advanced Combat Direction System (ACDS); Mk-2 Combat Control System (CCS Mk-2); Tomahawk Weapons Control System (TWCS); Ocean Surveillance Information System (OSIS) Baseline Upgrade (OBU); Flag Data Display System (FDDS); Tactical Electronic Reconnaissance Processing and Evaluation System (TERPES); Automated High Capability Area AAW Defense Weapon System Processing Capability for Digitized Integration with other elements of a ship's combat support system (AEGIS); Integrated Tactical Amphibious Warfare Data System (ITAWDS); US Army/US Air Force Electronic Shelters; Afloat Correlation System (ACS); Electronic Warfare Combat System (EWCS); Tactical EA-6B Mission Planning System (TEAMS); Prototype Ocean Surveillance Terminal (POST); Prototype Analyst Workstation System (PAWS); Constant Source Operator Terminal (CSOT); Control and Alert Reporting Terminal (CART); Tactical Receive Equipment Advanced Terminal (TREAT); Advanced Tracking Prototype (ATP); Tactical Receive Equipment Display (TRED); Tactical Data Information Exchange Subsystem (TADIXS); Prototype Air Reporting and Ground Operations Node (PARAGON); Synthesized UHF Computer Controlled Equipment Subsystem (SUCCESS).


1. Adapted from: Naval Education and Training Command, Naval Orientation, NAVEDTRA 12966, 0502-LP-213-4100, July 1991, page 12-16.

2. Adapted from: Naval Ocean Systems Center, "Navy UHF Satellite Communication System Description," FSCS-200-83-1, 31 December 1991.

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Maintained by Robert Sherman
Originally created by John Pike
Updated Sunday, May 04, 1997 1:30:52 PM