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.