防空識別圏
The first White House bunker was constructed during World War II to protect President Franklin D. Roosevelt in the event of an aerial attack on Washington. The modern PEOC space has modern communications equipment including televisions and phones to coordinate with outside government entities. During a breach of White House security, including violations of the Washington, D.C. Air Defense Identification Zone (P-56 airspace), the President and other protectees are relocated to the executive briefing room, next to the PEOC. Day to day, the PEOC is manned around the clock by joint-service military officers and non-commissioned officers.