 Ducky (David McCallum (I) (qv)) explains how SOS replaced CQD as  the international distress signal. In the movie  _Night to Remember, A (1958)_ (qv) McCallum played Titanics  Assistant Wireless Operator Harold Bride. During the Titanic  disaster Bride along with Wireless Operator John Jack Phillips  were the first two people in history to actually use the signal SOS.