Cal was a Master Sergeant and technical expert on a US Army Signal Corps team in Normandy following the D-Day invasion of France in June 1944. M/Sgt Sheckler and his crew established the cable head and cable station for a German cable diverted to Normandy by CS John W. Mackay. The cable was used for direct and secure transatlantic communication by the US Armed Forces in France for the duration of the war and after. History of the Atlantic Cable & Submarine Telegraphy - Transatlantic Cable Station "RM" in World War II