SECURE VOICE SUBSYSTEMSSIXS has undergone an upgrade (SSIXS II) thatreplaces the SSIXS shore equipment with newcomputer equipment.Message Traffic InputAt the broadcast control authority (BCA), theconsole keyboard operator, high-speed paper tapereader, or Submarine Message Automated RoutingTerminal (SMART) enters into the SSIXS shoreterminal messages addressed to submarines that havebeen received from AUTODIN, NAVCOMPARS, orlocally over the counter in the message center. Aboardthe submarine, message traffic is input via theteletypewriter or tape reader equipment. SSNsubmarines that have the Data Link Control System(DLCS) installed have an additional input/outputcapability via the sensor interface unit (SIU) for over-the horizon targeting (OTH-T messages.Rf Transmission Link ControlAshore, the SSIXS subsystem shares access to thesame satellite rf terminal equipment as the other uhfSATCOM subsystems, with the exception ofCOMSUBGRU SEVEN, Yokosuka, Japan, which isequipped with dedicated AN/WSC-3 transceivers.Since each BCA is located some distance awayfrom the Naval Computer and TelecommunicationsArea Master Station (NCTAMS), line modems andland lines are required for interconnection. Thesubmarine uhf rf terminal is the single-channel, half-duplex AN/WSC-3. SSIXS transmissions are at 4800bps. The capability to operate SSIXS in the DAMA net(see the section on DAMA) has been successfullydemonstrated and will be used in the future. Eachsubscriber to a SSIXS network is assigned a uniqueidentification number that is used in all transmissionsto or from the subscriber. The identification numbersare stored within the shore station and subscriberprocessors and are used for the following purposes:At the shore stations, the subscriber iden-tification number, when combined with broadcasts,determines the number of times message traffic istransmitted to the subscriber.When a subscriber makes a transmission to theshore station, the identification number is included. Theshore station will not acknowledge a transmissionwithout receiving the identification number.The subscriber uses the number to screenincoming message traffic. Any data that is notaddressed to that particular subscriber is discarded.3-10The Secure Voice subsystem enables thetransmission of ship-to-ship, ship-to-shore, and shore-to-ship voice communications via satellite relay.Figure 3-7 shows a Secure Voice subsystem.(AUTOSEVOCOM has been replaced by radiowireline interface (RWI) at all NCTAMS shoreactivities.) The subsystem transmits and/or receivessecure voice communications via a half-duplex, push-to-talk satellite link. Channels on each of the fourFLTSATCOM satellites have been allocated for use bythe Secure Voice subsystem. Control of the voicechannels is maintained by the Secure Voice controllerat the responsible NCTAMS/ NCTS.The subsystem uses digitized voice at a data ratelow enough to be compatible with a 3-kHz voicechannel and is considered narrowband. The sound ofNarrowband Secure Voice is very distinctive. Onceyou hear it, you won’t forget it. The system uses specialanalog-to-digital processing of the speech signal at thehandset terminal and the rf transmission rate is 2400bps.The Secure Voice subsystem has dedicated rfchannels on the uhf SATCOM satellites as well asdedicated DAMA time slots where DAMA nets havebeen established.Voice TransmissionThe rf terminal installations on mobile platformsdetermine the manner in which a Secure Voicetransmission is made. These mobile platforms maybecategorized into two types:The small ship/submarine that share a single-channel AN/WSC-3(V) uhf transceiver andcryptographic equipment between NAVMACS orSSIXS and a Secure Voice terminal.Larger ships that have two or more AN/ WSC-3(V) uhf transceivers and cryptographic equipment areinstalled. This installation normally has a transceiverdedicated to Secure Voice.Secure Voice use is accomplished by either of twomethods. In the first method, ships access a SecureVoice channel if the channel is not in use. The shipcontacts another ship directly by using the availablechannel. When coordination of voice communicationswith shore commands is required, the ship contacts thevoice controller who, in turn, tells the recipient(s) of anincoming voice transmission.
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