Executive Order 12472 establishes the National Communications System. Here are some excerpts.
Sec. 2. Executive Office Responsibilities.
(a) Wartime Emergency Functions.
The National Security Council shall provide policy direction for the exercise of the war power functions of the President under Section 606 of the Communications Act of 1934, as amended (47 U.S.C. 606), should the President issue implementing instructions in accordance with the National Emergencies Act (50 U.S.C. 1601).
The Director of the Office of Science and Technology Policy shall direct the exercise of the war power functions of the President under Section 606 (a), (c) - (e), of the Communications Act of 1934, as amended (47 U.S.C. 606), should the President issue implementing instructions in accordance with the National Emergencies Act (50 U.S.C. 1601).
Sec. 3. Assignment of Responsibilities To Other Departments and Agencies.
(a) Department of Commerce. The Secretary of Commerce shall, for all conditions of crisis or emergency:
Develop plans and procedures concerning radio spectrum assignments, priorities and allocations for use by Federal departments, agencies and entities; and
Develop, maintain and publish policy, plans, and procedures for the control and allocation of frequency assignments, including the authority to amend, modify or revoke such assignments, in those parts of the electromagnetic spectrum assigned to the Federal government.
(b) Department of Homeland Security. The Secretary of Homeland Security shall:
Plan for and provide, operate and maintain telecommunications services and facilities, as part of its National Emergency Management System, adequate to support its assigned emergency management responsibilities;
Advise and assist State and local governments and volunteer organizations, upon request and to the extent consistent with law, in developing plans and procedures for identifying and satisfying their national security or emergency preparedness telecommunications requirements;
Ensure, to the maximum extent practicable, that national security and emergency preparedness telecommunications planning by State and local governments and volunteer organizations is mutually supportive and consistent with the planning of the Federal government; and
Develop, upon request and to the extent consistent with law and in consonance with regulations promulgated by and agreements with the Federal Communications Commission, plans and capabilities for, and provide policy and management oversight of, the *Emergency Alert System, and advise and assist private radio licensees of the Commission in developing emergency communications plans, procedures and capabilities.
(* - Changed by Executive Order dated June 26, 2006 from Emergency Broadcast System to Emergency Alert System. )
(c) Department of State. The Secretary of State, in accordance with assigned responsibilities within the Diplomatic Telecommunications System, shall plan for and provide, operate and maintain rapid, reliable and secure telecommunications services to those Federal entities represented at United States diplomatic missions and consular offices overseas. This responsibility shall include the provisions and operation of domestic telecommunications in support of assigned national security or emergency preparedness responsibilities.
(d) Department of Defense. In addition to the other responsibilities assigned by this Order, the Secretary of Defense shall:
Plan for and provide, operate and maintain telecommunications services and facilities adequate to support the National Command Authorities and to execute the responsibilities assigned by Executive Order No. 12333; and
Ensure that the Director of the National Security Agency provides the technical support necessary to develop and maintain plans adequate to provide for the security and protection of national security and emergency preparedness telecommunications.
Nothing in this order shall be construed to impair or otherwise affect the authority of the Secretary of Defense with respect to the Department of Defense, including the chain of command for the armed forces of the United States under section 162(b) of title 10, United States Code, and the authority of the Secretary of Defense with respect to the Department of Defense under section 113(b) of that title.
(e) Department of Justice. The Attorney General shall, as necessary, review for legal sufficiency, including consistency with the antitrust laws, all policies, plans or procedures developed pursuant to responsibilities assigned by this Order.
(f) Central Intelligence Agency. The Director of Central Intelligence shall plan for and provide, operate, and maintain telecommunications services adequate to support its assigned responsibilities, including the dissemination of intelligence within the Federal government.
(g) General Services Administration. Except as otherwise assigned by this Order, the Administrator of General Services, consistent with policy guidance provided by the Director of the Office of Management and Budget, shall ensure that Federally owned or managed domestic communications facilities and services meet the national security and emergency preparedness requirements of the Federal civilian departments, agencies and entities.
(h) Federal Communications Commission. The Federal Communications Commission shall, consistent with Section 4(c) of this Order:
Review the policies, plans and procedures of all entities licensed or regulated by the Commission that are developed to provide national security or emergency preparedness communications services, in order to ensure that such policies, plans and procedures are consistent with the public interest, convenience and necessity;
Perform such functions as required by law with respect to all entities licensed or regulated by the Commission, including (but not limited to) the extension, discontinuance or reduction of common carrier facilities or services; the control of common carrier rates, charges, practices and classifications; the construction, authorization, activation, deactivation or closing of radio stations, services and facilities; the assignment of radio frequencies to Commission licensees; the investigation of violations of pertinent law and regulation; and the initiation of appropriate enforcement actions;
Develop policy, plans and procedures adequate to execute the responsibilities assigned in this Order under all conditions or crisis or emergency; and
Consult as appropriate with the Executive Agent for the NCS and the NCS Committee of Principals to ensure continued coordination of their respective national security and emergency preparedness activities.
http://www.ncs.gov/library/policy_docs/eo_12472.html