The Central Bureau was one of two Allied signals intelligence (SIGINT) organisations in the South West Pacific area (SWPA) during World War II. Central Bureau was attached to the headquarters of the Allied Commander of the South West Pacific area, Douglas MacArthur. Central Bureau's role was to research and decrypt intercepted Imperial Japanese Army (land and air) traffic and work in close co-operation with other SIGINT centres in the USA, United Kingdom and India. Air activities included both army and navy air forces, as there was no independent Japanese Air Force. The other unit was the joint Royal Australian Navy/United States Navy Fleet Radio Unit, Melbourne (FRUMEL), which reported directly to C-in-C, Pacific (Admiral Chester Nimitz) in Hawaii and the Chief of Naval Operations (Admiral King) in Washington. Background General Douglas MacArthur had his own signals intelligence unit, Station 6, while he was in command in the Philippines before the War started, and was not fully dependent on the U.S. Navy for that type of information. However, most of the signals intelligence he received was from the Navy unit, Station CAST, originally at Cavite in the Manila Navy Yard, and evacuated to Corregidor Island after Japanese successes. Prior to the war, it had to be sent by courier, which caused some delay and annoyance. General MacArthur escaped from Corregidor in the Philippines in a PT boat to Mindanao and flew to Australia from Del Monte on a Boeing B-17 Flying Fortress. He made his way to Melbourne, arriving there on 22 March 1942. The Signals Intelligence units operating in Australia at the time of MacArthur's arrival in Melbourne were as follows: No. 4 Australian Special Wireless Section at Park Orchards near Ringwood in Melbourne A small Diplomatic and Press intercept section at Park Orchards A Diplomatic cryptographic and intelligence section at Victoria Barracks, Melbourne Some British Army Signals personnel from the Far East Combined Bureau who had escaped from Java A small RAAF Intercept section in Darwin A small RAN intercept and Direction Finding (D/F) organisation A small RAN cryptographic and intelligence section at the Navy Office in Melbourne and, eventually, after evacuation from Corredigor by submarine, the personnel of Station CAST, the US Navy SIGNIT group in the Far East One of his first decisions when he arrived in Melbourne was to expand the SIGINT operations already existing in Australia. Some personnel of the United States Navy crypto group