FIlter Room

Filter rooms were the center of the radar system. In Britain there were seven filter rooms, one for each designated region, and in Canada there was a filter room on each coast. Filter rooms and radar stations were connected by private phone lines. Personnel on a radar stations would phone in information to the filter room, where it would be interpreted and filtered out before being displayed on a plotting table. Senior officers would give orders based on the information displayed on the plotting table; to turn on the air raid sirens, scramble a team of jets to intercept incoming enemy aircraft, or offering support and assistance to incoming allied aircraft. In Britain, the filter rooms were staffed mostly by Women’s Auxiliary Air Force personnel who were selected for their ability to think quickly, work well with numbers, and maintain focus and accuracy in a high-stress environment.