EAC Signal Support.
(1) The theater communications system (TCS) provides signal support at EAC. Due
to the nature of the environment, the TCS is a multi-service (Army, Navy, Air Force, and Marine
Corps) responsibility. In addition, the TCS may include allied and host nation communications
systems and equipment. Communications at the theater level is supplied by an integrated system
that supports the major units and headquarters (HQ) within the theater of operations. The U.S.
unified commander is responsible for providing communications between the unified HQ and the
U.S. service component HQ, and to other U.S. government agencies and allied commands within
the theater as required. The U.S. unified commander normally assigns communications tasks to
service component commanders.
(2) Each service component generally installs its own portion of the TCS. One
service, normally the predominant service, installs the backbone system with the other services
connecting to it for their own purposes. This is usually the case for the Army as the predominant
service in a land theater. The Army's portion of the TCS is known as the theater
communications system (Army) or TCS(A). It is a subset of the TCS, which supports only Army
forces and operations. For the purposes of this lesson, only the TCS(A) will be discussed in
reference to EAC signal support.
(3) The TCS(A) is installed by the theater signal command (Army) or TSC(A),
formerly known as the theater communications command (Army). The TSC(A) connects the
theater army commander with his subordinate commands within the theater, and provides access
to the corps system. The TSC(A) is a major functional command of the theater Army and is
under the operational control of the theater army in both peacetime and wartime. The TSC(A)
usually consists of two to five theater signal brigades; the actual number depends on the size and
mission of the theater army. The theater signal brigade is not a set organization like the division
signal battalion, but is tailored to meet the needs of the theater. Various signal units (battalions
and companies) are grouped together like basic building blocks to form a type TSC(A).
(4) The TCS(A) is an integrated nodal communications system that emphasizes
common-user access and switching. It consists of an area network system (Figure 3-1) and
command links (Figure 3-2, page 3-4) between major Army commands. Figure 3-1 is an
example of a theater area network. The large triangles represent area nodes, each of which
incorporates switching, transmission, multiplex, and local subscriber services. The hexagons and
small triangles represent those nodes which are support signal centers for HQ. As shown Figure
3-1, the heater area nodal system connects with a minimum of two nodes within each corps area
system to provide access to the corps communications network.