Telegraph communication across the Atlantic began in 1866, when a cable was successfully laid between Newfoundland and Valencia, Ireland. The first commercial voice link across the Atlantic was inaugurated in 1927 with a single radio telephone circuit. During the 1940s, however, the necessary equipment was gradually developed. The elements necessary for transatlantic telephony by cable included coaxial cables with polythene (polyethelene, or polymerized ethylene) insulation. The Bell System approached the British Post Office to invite collaboration, together with the Canadian Overseas Telephone Corporation to lay a system across the Atlantic. In November 1953, they signed the Transatlantic Cable Construction and Maintenance Contract to complete the system by 1956.