Dated 1840-1850. From Scientific apparatus, musical instruments and telegraph equipment, [1834-1875].
ABC transmitting telegraphs designed by Wheatstone using a step by step mechanism. The dial is rotated to the required character which operates ‘make and break’ contacts beneath the dial sending current impulses down the line to the receiver. [See K/PP107/1/4/42]. Brass dial mechanism with 30 arms each marked with letters and numbers radiating from a brass plate attached to a mahogany base.