Morse Code in 1912 did not sound like the neat beeps and boops we often hear in movies. It was basically playing with crashes of static. This signal was recreated for the Titanic Historical Society using vintage equipment, and it's an exact recreation of what the radio operators would have heard that night. As best as my rudimentary Morse code skills allow, the message translates as follows:
CQD CQD SOS SOS CQD DE MGY MGY MGY
"CQD" was the standard distress call at the time; there were a whole series of "CQ" codes, and the "D" meant distress. In 1909, an international convention adopted "SOS" as the new distress signal-- not because it means "save our souls," as is often reported, but because the three dots, three dashes and three dots are a very distinctive signal that cannot be confused with anything else, especially by those not very familiar with Morse. (Even you can hear it, right?) "MGY" were Titanic's call letters. And the "DE" means "this is."
Imagine sitting in some radio shack on one of the many ships in the North Atlantic that cold, still night, listening to the staccato mutter of the Morse spark, and suddenly hearing this call out of the ether. Anyone who heard the call that night remembered to his dying day the hair rising on the back of his neck at the almost incomprehensible message -- the Titanic in distress.