FM 63-2

                                                                                Chapter 4

                   CONTENTS                                                                                                                          PAGE
                   PRINCIPLES AND DEVELOPMENTS IN COMMUNICATIONS SYSTEMS ., . . . . . . . . ...4-1
                   CURRENT AREA SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...4-1
                   COMBAT NET RADIO SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
                   DISCOM HHC/DMMC RADIO NETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
                   COMSEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..4-14
                   OPSEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...4-16
                   AUTOMATION SYSTEMS SECURITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-17

   Communications are essential for gathering data                                            radios and AM (AN/GRC-106) radios will be replaced
and planning operations and supervising performance.                                          by the SINCGARS and the improved high frequency
Communications are also essential for performing C2                                           radios.
functions. Effective management of DISCOM                                                         These changes will affect the DISCOM in the area
functions depends on adequate communications to                                               of connectivity to the area system. The command
keep abreast of changing situations and require-                                              operations company of the division signal battalion
ments.                                                                                        installs, operates, and maintains the automatic
   The DISCOM relies on its organic communications                                            telephone and switchboard facilities for access to
assets and the division signal battalion for communications                                   the area system. The company also installs and main-
support. A large number of units operate in the DSA.                                          tains local subscriber circuits. Under MSE, DISCOM
This density factor may require support units to find                                         personnel will run wire from unit locations to the
alternate methods for communication. The length of                                            MSE interface point. The amount of wire needed is
transmissions and the accuracy with which they are                                            based on the dispersion requirements of the particular
sent directly affect the support mission. CSS planners                                        situation.
should consider using couriers and wire communications                                            With the deployment of MSE, the wire-laying for
as alternatives for getting the support mission done.                                         all units will have to be covered by unit SOP. It must
These alternatives lessen the security risk of substantial                                    cover who does it and in what priority, The actual
radio use.                                                                                    communications means will remain essentially the
    Communications equipment and systems in the corps                                         same. The DISCOM will depend on combat net
and division are changing. The current area communica-                                        radios and wire to access the area communications
tions system is described below. This system will be replaced                                 system. Automated hardware systems terminals will
by the MSE system. Current FM (AN/VRC-12 series)                                              be subscribers to the area system via wire.

                                                          CURRENT AREA SYSTEM
   Figure 4-1 depicts the current area communications                                              q    Installs and maintains cable and wire for local
system. The command operations company of the division                                                  telephone circuits. DISCOM personnel will help
signal battalion provides communications support for                                                    the signal battalion personnel during the initial
the DISCOM HHC/MMC. The following is a list of the                                                      installation.
communications facilities and services provided by this                                            q   Installs and operates the multichannel terminals
company:                                                                                               in the division communications system.
    q Installs and operates a radio teletypewriter terminal
                                                                                                   q   Installs, operates, and maintains automatic telephone
       in the division’s general purpose net.                                                          and switching facilities. These facilities provide

FM 63-2

      Figure 4-1. Sample armored/mechanized infantry division multichannel diagram (current area system).
                                                                                                             FM 63-2

      access to the area system and local telephone             Telephone installer-repairer personnel install
      subscriber circuits (DISCOM switchboard).               and maintain local telephones for the DISCOM
      Provides telephone equipment for the DISCOM             headquarters.
      HHC and DMMC (see Figure 4-2).                            Under MSE, the existing 2-wire switchboards and
      Provides a record traffic receiving and distribu-      telephones will not be compatible with the 4-wire
      tion center.                                           digital system. The DISCOM HHC, however, will
                                                             keep the switchboard for internal operations and for
      Installs and operates a net radio interface facility   local security.
      for single channel voice radio access to the
      division’s telephone system.

   MSE is the area common user voice communications          Switchboard locations cannot be consistently related to
system within the corps. It is the primary means for         specific units.
command and control from the corps rear to brigade
rear. It will be deployed from the corps rear boundary                  WIRE SUBSCRIBER ACCESS
forward to the maneuver battalion main CP. The MSE              Wire subscriber access points will provide
system is comprised of four functional areas:                the entry point (interface) between fried subscriber
   q Area coverage.
                                                             terminal and the MSE area system. The fixed sub-
                                                             scriber terminal and its equipment are owned and
    q Wire subscriber access.                                operated by the users. The signal units operate the
   q Subscriberterminals.                                    MSE area system. Figures 4-6 and 4-7, page 4-8,
   q Mobile subscriber access.
                                                             show the MSE switchboard configurations. It is
                                                             through one of these configurations that the DISCOM
                AREA COVERAGE                                HHC/MMC ties into the area system,
   Area coverage means that MSE provides common                 The following are the two types of interface points:
user support to a geographic area, as opposed to
                                                                q  The signal distribution panel (junction box)
dedicated support to a specific unit or customer.
                                                                   J1077. Each panel can provide up to 13 subscriber
Figure 4-3, page 4-5, shows the deployment of area
                                                                   access points.
nodes across a corps area. These nodes are called
node centers. These centers are shown in Figure 4-4,             q Remote multiplexer combiners which provide
page 4-6. They are under the control of the corps                  up to eight subscriber access points.
signal officer,                                                 Beyond these two interface points, the using units
   At division level, the signal battalion operates four     are responsible for the installation and operation of
of these nodes. The small and large node extension           fixed subscriber terminal instruments. They are also
switchboards are connected to these nodes via line-          responsible for the installation and maintenance of
of-sight radios. The following switchboards are              the WF 16 field wire from the instruments to the
organic to the division signal battalion:                    interface points into the area system.
   q 16  SEN switchboards capable of supporting 26                  SUBSCRIBER TERMINALS (FIXED)
      to 41 subscribers each.                                   Subscriber terminals used by the DISCOM are
   q 1 LEN switchboard capable of supporting 176             digital nonsecure voice telephones. These provide
      customers.                                             full duplex digital, 4-wire voice as well as a data port
   Figure 4-5, page 4-7, shows a typical deployment          for interfacing the AN/UXC-7 facsimile (informal
of switchboards within the division. The G3 will             record traffic). The TACCS computers (for CSS
determine the location of switchboards based on the          STAMIS), the AN/UGC-144 (single subscriber
recommendations of the division C-E officer.                 terminal for formal record traffic), the unit-level
                                                             computers (for the unit-level logistics STAMIS),
   The C-E officer considers the commander’s intent,         and the ATCCS (for the CSSCS) will interface
customer requirements, and other factors of METT-T.          through these terminals. Figure 4-8, page 4-9),

FM 63-2

          Figure 4-2. DISCOM HHC/MMC wire net.

                                                FM 63-2

Figure 4-3.   Deployment of area nodes (MSE).
FM 63-2

          Figure 4-4. Node center.
                                                                      FM 63-2

Figure 4-5. Sample division deployment of SEN and LEN switchboards.

FM 63-2

            Figure 4-6. LEN switchboard interface.


          Figure 4-7. SEN switchboard interface (V2).

                                                                       FM 63-2

Figure 4-8. DISCOM subscriber terminal assignment, fixed and mobile.

FM 63-2

portrays the assignment of this equipment for the              typical MSRT interface into the area system. RAUs
DISCOM HHC/MMC.                                                are deployed to maximize area coverage and MSRT
                                                               concentrations. MSRTs can also operate in CPs
                                                               to allow access to staff and functional personnel.
   The MSE mobile subscriber terminal is the                   Figure 4-8 represents assignment of MSRTs in the
AN/VRC-97 mobile subscriber radiotelephone terminal.           DISCOM, The MSRT user will have a KY68
This MSRT consists of a very high frequency radio and          telephone connected to the radio mounted on his
a digital secure voice terminal. This is a vehicle-            vehicle. As long as the radio unit has line-of-sight
mounted assembly. The MSRT interfaces with the                 contact with the RAU, it has connection into the area
MSE system through a radio access unit. The primary            system. The operational planning range is 15
use of the MSRT is to provide mobile subscribers               kilometers from any RAU.
access to the MSE area network. Figure 4-9 portrays a

                                        COMBAT NET RADIO SYSTEM
   The combat net radio structure is designed around               Current CNR equipment in the DISCOM consists
three separate radio systems; each has different               of the AN/GRC-106 and the AN/VRC-12 series
capabilities and transmission characteristics. The             radios. These will be replaced by IHFR and
three systems are –                                            SINCGARS series respectively. SINCGARS is a new
    q SCOTT.                                                   family of VHF-FM radios. These radios are designed
                                                               for simple, quick operation using a 16-element
   q IHFR.
                                                               keypad for push-button tuning. They are capable of
   q SINCGARS.                                                 short-range or long-range operation for voice or digital
   SCOTT is a stand-atone transportable tactical satellite     data communications. The planning range is 8 to 35
communications terminal. The other two systems, IHFR           kilometers. They also operate in a jam-resistent, frequency-
and SINCGARS, will provide means of voice transmis-            hopping mode. This can be changed as needed. IHFR
sion of C2 information. They will also provide                 is a family of high frequency radios. Radios include the
means for data transmission. This will be necessary if         AN/PRC-104 manpack radio and the AN/GRC-193
data transfer requirements cannot be met by the                vehicular radio.
MSE system.

                                     DISCOM HHC/DMMC RADIO NETS
                DISCOM COMMAND/                                the DMMC for coordination of critical areas (Class I, III, V
              OPERATIONS NET (FM)                              and maintenance management). The net control stat ion
   The DISCOM command/operations net is the                    is the DISCOM materiel management office.
principal net operated by the DISCOM headquarters.                            Class I and Class III and
See Figure 4-10, page 4-12. This net is a backup to                       Water Supply Branch Officers
MSE. It is used to command and control elements
                                                                  These branches are subordinate to the general supply
of the DISCOM in the performance of its logistics
                                                               section. However, they are also distinct operating
mission. The net control station is the S2/S3
                                                               entities within the DMMC. The Class I supply
section. Stations in this net monitor the division
                                                               branch officer has a radio for Class I operations. The
command/operations net and the division intel-
ligence net. This net is also used for rear operations as      Class III and water supply branch officer has a radio
required.                                                      for Class III operations. Each branch uses the mobile
                                                               station in this net. This is done to coordinate with
                   DISCOM MATERIEL                             other DISCOM elements on issue points, problems,
              MANAGEMENT NET (FM)                              shortages, excesses, and requirements. Agents of
   This net supports the technical aspects of logistics        these branches are constantly traveling within the
support to the division. See Figure 4-11 page 4-13. It main-   division and brigade areas to ensure the smooth
tains continual communications between components of           functioning of their respective supply operations.

                                           FM 63-2

Figure 4-9. Mobile subscriber interface.

FM 63-2

          Figure 4-10. Heavy DISCOM command/operations net (FM).
                                                    FM 63-2

Figure 4-11. DISCOM materiel management net (FM).

FM 63-2

         Class II-IV Supply Branch Technician               the ATPs. The ATP NCOs have a radio and can com-
   The Class II-IV supply branch technician does not        municate with these two sources for their information
have a radio assigned to the section. He has access to      and guidance.
the net by using radios assigned to other branches in the                       Materiel Officer
DMMC. The layout of the DMMC will determine
                                                               The materiel officer uses his mobile station in this
which branch radio he will use.
                                                            net to coordinate with the DMMC. This allows for the
             Class V Supply Section Officer                 quick resolution of materiel problems throughout
   The DAO uses the materiel management net to              the division.
provide coordination and control necessary to monitor                DISCOM LOGISTICS OPERATIONS
ammunition supply. The DAO uses a mobile station                                 NET (AM-SSB)
in this net to solve problems while on the move. The           This net provides along-range command and control
DAO must always be able to communicate with
                                                            link for the DISCOM. This is especially helpful when
the DMMC chief. The DAO communicates with
                                                            the division is operating over extended distances. It also
the G3 and the COSCOM MMC Class V section                   provides a long-range link to the COSCOM elements
via the area communications system. He communicates
                                                            as required. The net control station for this net is the
with each support battalion via the materiel manage-
                                                            DISCOM support operations branch (Figure 4-12).
ment net.
   Within this net, the DAO has a radio. The am-                      DISCOM MEDICAL OPERATIONS
munition supply technician, the chief ammunition                                 NET (AM-SSB)
NCO, and the ammunition inspection NCO share a                 The chief of the DMOC uses this net to coordinate
radio. They normally operate from the DMMC                  patient medical regulating, air/ground evacuation, and
field location. The two radios are in separate trucks.      emergency medical resupply. This coordination is with
These radios provide a communication link with the          the division medical companies and corps medical brigade
division and brigade ammunition NCOs located at             elements (Figure 4-13).

   COMSEC consists of measures taken by a unit to              COMSEC materiel must be requested in advance.
prevent unauthorized persons from gaining information       The COMSEC custodian must be informed at least
of value from communications. It includes crypto-           24 hours prior to the requested pickup time. Users
security, physical security, transmission security, and     are issued COMSEC materiel on a SF153 (Hand
emission security.                                          Receipt).
   Supervisors must prescribe policies and procedures          Hand-receipt holders/users physically verify the
for safeguarding COMSEC materiel during tactical            serial numbers and quantity of COMSEC materiel they
operations. They must also provide instructions for         are receiving against the hand receipt. This is done
implementing emergency procedures during operations.        prior to signing for the materiel and ensures there are
The responsibility for safeguarding classified COMSEC       no discrepancies. These hand-receipt holders cannot
information rests not only with the commander but           and will not subhand-receipt COMSEC materiel they
with every individual in the command. This especially       have on hand receipt without prior approval of the
applies to those people who handle, store, use, or have     COMSEC custodian.
knowledge of subject information.                              The prompt reporting of physical and cryptographic
   The sensitivity of COMSEC information dictates           security violations and compromises is essential to the
that it be available only to those personnel who have a     maintenance of adequate communications security. A
need to know. A person’s office, position, or security      compromise results from any occurrence that enables
clearance does not automatically entitle him access to      unauthorized persons to derive useful information from
COMSEC information. However, all personnel who              encrypted communications.
require access to classified COMSEC information must           A compromise may result from either of two
have the appropriate security clearance.                    types of insecurities. Physical insecurities occur

                                                         FM 63-2

Figure 4-12. DISCOM logistics operations net (AM-SSB).

     Figure 4-13. DISCOM medical HF voice net.

FM 63-2

when classified information is lost or possibly ex-             Any known or suspected compromise or other
posed to an unauthorized person. This includes               security violation must be reported immediately to the
information subject to compromise through personnel          commander, COMSEC custodian, or supervisor. He will
insecurities. Personnel insecurities include detection,      in turn determine the necessary actions to be taken.
unauthorized absence, deliberate or inadvertent dis-            Destroy all superseded COMSEC materiel beyond
closure to an unauthorized person, and the removal of        recognition.
a security clearance for cause.

   OPSEC deals with protecting friendly military             EEFI. The threat profile should evaluate foreign
operations and activities by identifying the EEFI and        intelligence awareness, their motivation, and
providing appropriate protection to those EEFI. It           their capability to collect information. The profile
aids in keeping the enemy from learning how, when,           should also give you what the probability will be of your
where, and why US forces do something. A basic               operation, activity, or project being targeted. Collection
OPSEC program would consist of four phases.                  of intelligence information by foreign intelligence
                                                             service is accomplished by a variety of means. The
                                                             following disciplines normally will be included in a
     ELEMENTS OF FRIENDLY INFORMATION                        multisource intelligence threat:
                                                                q HUMINT is intelligence obtained by using
    Initially, the commander identifies what operations,
activities, and projects must not be compromised to                people to gather various items of information.
ensure accomplishment of his overall mission. These                HUMINT collection involves both overt and
identified areas are translated into the command’s                 clandestine operations. Examples of overt
security objectives. The CSO are usually stated broad              operations would include information obtained
terms (for example, “prevent technology transfer of                from public records and unclassified publications”; “achieve surprise fielding of the               and newspapers. Clandestine operations include
...weapon systems”; or “prevent disclosure of the unit’s           people eavesdropping on conversations and
readiness and deployment posture”). CSO properly                   conducting surveillance or special operations.
stated indicate “what we are doing and why we are                q SIGINT is intelligence obtained by intercepting
doing it.”                                                         electronic signals. This information is obtained
    The CSO are used as a basis to develop EEFI. EEFI              by intercepting telecommunications signals,
are specific, critical, and sensitive items of information         such as telephone or radio conversations (normally
that individually or collectively need protecting.                 referred to as COMINT). Information also
Protection will preclude the compromise of the CSO.                is obtained by intercepting electromagnetic
Information such as specific dates, times, locations,              nondata-related radiations, such as radar signals
intentions, and capabilities may need to be protected.             (normally referred to as ELINT). Signal security
                                                                   is an overall term for the security measures taken
    EEFI can include both classified and sensitive                 to deny collection of information from COMINT
unclassified information. Sensitive, unclassified                  and ELINT operations.
information is information which could give an insight
                                                                q IMINT is intelligence obtained through the use
into an area of classified information or divulge CSO. A
combination of more than one piece of sensitive,                   of photographic, infrared, or radar imagery
unclassified information may contain sufficient detail             equipment. Satellites, aircraft, and land or sea
to warrant classification. Disclosure of this sensitive,           based vehicles/vessels can house imagery equip-
unclassified information could have negative results on            ment. IMINT also can be provided by human
future operations, activities, or projects.                        sources who employ imagery equipment.

   The threat is determined by evaluating the                   The unit OPSEC officer works with the CI section to
capabilities of foreign intelligence services to collect     develop a unit profile. With a profile, the OPSEC
                                                             officer can determine what information a foreign

                                                                                                           FM 63-2

intelligence service might collect. This profile allows a   takes place, further action is no longer required.
unit to see itself as the enemy would see it. A profile     Where extensive corrections must be taken or high
consists of patterns and signatures, Patterns are           costs are involved, recommendations should be
stereotyped actions which so habitually occur in a given    prioritized to permit an incremental approach
set of circumstances that they cue an observer (foreign     for adoption that is phased over a period of time. A
intelligence service). So habitual are these actions,       commander’s decision on what countermeasures
that the observer is able to determine the type             to implement relate directly to risk versus cost benefit.
operation/activity/project, its capabilities, or its           Principal components of any OPSEC program
intent. Signatures provide the identification of the        include physical security, information security,
operation/activity/project. Signatures result from          signal security, security education, and at times,
unique visual (imagery), electromagnetic, olfactory,        deception operations.
or sonic displays. A unit profile is developed by a
team. The team should observe every facet of the               Physical security measures may include a badge
operation to identify patterns and signatures. The          and pass system, security guards, and perimeter
team members should be knowledgeable in specific            fencing. Such measures should be included, as ap-
aspects of the operation/a ctivity/project. Separate        propriate, when you develop your OPSEC program.
profiles should be developed for the following areas:       A good reference for physical security is FM 19-30.
operations/maneuvers, communications/electronics,              Information security is also of vital importance
intelligence, logistics, and administration/support.        to the OPSEC program. Security procedures, such
                                                            as using only approved storage containers, double-
                                                            checking offices prior to departure, and ensuring
   Once the threat is identified and a profile              the “need-to-know,” are measures that can be
developed, a risk assessment is prepared. The assess-       taken to protect classified and sensitive, unclassified
ment centers on the operation/activity/project’s            information. AR 380-5 contains important provisions
vulnerability to collection. All EEFI must be               dealing with information security.
considered in this assessment. The assessment considers
numerous factors. Examples of some factors are                 SIGSEC includes all measures taken to deny
the project sensitivity, or the known, or suspected         collection of information from both COMINT
collection priority by foreign intelligence service.        and ELINT operations. Something as simple
The operating environment, the proximity to inter-          as not discussing classified or sensitive, unclassified
national borders, and security programs are some            information over the telephone can greatly assist in
additional factors. Security education as well as           maintaining the security of an operation, installation,
physical and natural barriers are also factors to be        or activity.
considered. An assessment of where, how, and why               Security education consists of initial security
an operation/activity/project is vulnerable naturally       orientations, refresher briefings, foreign travel
leads to recommendations on how to reduce these             briefings, and debriefings. The focus of the training
vulnerabilities.                                            and education program is to highlight to all personnel,
   A countermeasure is any action taken to eliminate        the threat that exists to classified and sensitive,
or reduce a vulnerability to collection. When recom-        unclassified information. The program also provides
mending countermeasures, planners should consider           measures to be taken to reduce that threat to the
                                                            lowest practical level. One objective of any security
on-the-spot corrections which effectively minimize
or neutralize identified vulnerabilities. Low cost/no       education program is to convince the individual that
cost solutions must be sought and emphasized. Such          this is information he needs to learn. Without an
recommendations may be of a temporary or permanent          awareness of the need for security on the part of all
nature. Temporary recommendations to neutralize a           personnel, other security measures, such as fences,
vulnerability usually relate to an event. When the event    guards, and alarms, are reduced in effectiveness.

                                 AUTOMATION SYSTEMS SECURITY
   Automated systems are vulnerable to destruction,         physical security of hardware devices but security of
sabotage, and compromise. Security includes not only        programs and procedures. Detailed guidance on

FM 63-2

automated systems security is provided in AR 380-380.             q Restrict access to the computer site by the use
The following physical and security practices must be               of classified passwords.
established for use of TACCS or other microcomputers –            q Rotate  unique operator passwords every 30 days
    q Locate the computer within an enclosure that                  or less.
       provides controlled access.                                q Control   all log-ons and file access by unique
    q Secure all electrical facilities that support the system.     operator passwords.
    q Store magnetic media storage containers at least            q Monitor device usage.
      20 inches from an exterior wall. (This helps                q Restrict the access of visitors.
      provide protection against the potential effects
                                                                  q Monitor report distribution plans.
      of magnetic fields or radiation.)
                                                                  q Reduce the number of copies of each report.
    q Restrict physical access to magnetic diskettes.
                                                                  q Destroy all printouts of reports and lists as new
    q Require that authorized operators have at least
      an interim confidential security clearance.                   ones are printed.


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