Morse sounder, c.1880. Double plate sounder., in wooden case with needle and dial at the top. Last used over railway telegraph circuits to transmit Morse code through a reversal of the current to distinguish dot from dash. The needle moved to left and right. Morse code sounder used over railway telegraph circuits Telecommunications c.1880
Neale's acoustic dial (a type of Morse sounder), used by the General Post Office. Neale's acoustic dial (a type of Morse sounder) Telecommunications c.1900
