English: A replica of the radio room on the ocean liner RMS Titanic which hit an iceberg and sank on its maiden voyage 15 April 1912. An SOS distress signal sent from this room summoned a nearby ship, the RMS Carpathia, which saved 705 of the survivors. Two men employed by the Marconi Company worked in this small windowless room near the bridge. Their main job was to receive and send messages by radio waves using Morse code. Little did they know they would soon be tapping out one of the first SOS signals from a ship in distress. The radio apparatus during the wireless telegraphy or "spark" era before 1920 was primitive; a spark-gap transmitter which transmitted information by the operator tapping on a telegraph key to spell out messages in Morse code, and a weak unamplified crystal radio receiver.