Gerke was an inspector of the optical Hamburg-Cuxhaven telegraph line when William and Charles Robinson introduced the Morse telegraph to Hamburg in 1847. He switched to the new electrical telegraph line, installed the wire lines with Robinson, and learned the new technology. Gerke revised Alfred Vail's original Morse alphabet, which was difficult to read. Gerke's system was adopted by the German-Austrian Telegraph Association in 1851 and by the International Telegraph Union in 1865.