On April 14, 2004 (February 25, 2004 in the lunar calendar), China's first large-capacity Eurasian terrestrial optical cable network was opened. On April 14, 2004, China's first large-capacity Eurasian terrestrial optical cable network was opened, which is another terrestrial transmission channel after submarine cable and satellite transmission. This Eurasian land optical cable network, jointly built and maintained by China Unicom, Mongolia Railcom and Russia Railcom, has a total length of 7,500 kilometers.