Telecommunications in India began with the introduction of the telegraph. The Indian postal and telecom sectors are one of the worlds oldest. In 1850, the first experimental electric telegraph line was started between Calcutta and Diamond Harbor. In 1851, it was opened for the use of the British East India Company. The Posts and Telegraphs department occupied a small corner of the Public Works Department at that time. In 1880, two telephone companies namely The Oriental Telephone Company Ltd. and The Anglo-Indian Telephone Company Ltd. approached the Government of India to establish telephone exchange in India. The permission was refused on the grounds that the establishment of telephones was a government monopoly and that the Government itself would undertake the work. In 1881, the Government later reversed its earlier decision and a license was granted to the Oriental Telephone Company Limited of England for opening telephone exchanges at Calcutta, Bombay, Madras and Ahmedabad and the first formal telephone service was established in the country. Some major telecom operators in India include the privately-owned companies like Vi, Airtel, and Reliance Jio and the state-owned companies - BSNL and MTNL.