In 1931, two worldwide communications companies established the remaining antenna fields and buildings at Point Reyes. American Telephone and Telegraph's radio-telephone station KMI provided two-way voice services between ships at sea or aircraft and telephones on land, sea, or in the air, while the Radio Corporation of America's station KPH provided commercial communication services to ships at sea through Morse code. Both stations assisted ships by broadcasting weather and gave top priority to distress calls, providing lifesaving services at sea. On December 31, 1931, radio-telephone communications was established between the AT&T station and Hawaii. The Atlantic had been bridged by radio-telephone only two years before direct service was established between this station and Sydney, Australia. By 1940, subscribers of the Pacific Telephone Company were linked to over 90 percent of the world's telephones by AT&T's three High Sea's stations: KMI in Point Reyes, WOO in New Jersey, and WOM in Florida. Wave propagation technology later became obsolete and was replaced by satellite communications, and the Point Reyes AT&T station closed on October 13, 1999. Sky-wave propagation, which made high seas communications possible, worked by having radio signals refracted by electrically conductive layers in Earth's upper atmosphere, or ionosphere, and bounced back to Earth many miles from the point of emission.