Samuel F. B. Morse conceived of an electromagnetic telegraph in 1832 and constructed an experimental version in 1835. He did not construct a truly practical system until 1844, when he built a line from Baltimore to Washington, D.C. 
This model incorporates basic features of the 1844 receiver. It accompanied an application for a patent, granted in 1849, in which he described a method for marking dots and dashes on paper. 
Within ten years after the first telegraph line opened, 23,000 miles of wire crisscrossed the country. The invention profoundly affected the development of the West, made railroad travel safer, and allowed businessmen to conduct their operations more profitably. 