Today, 34 years ago, on September 22, 1991 (August 15, 1991) the international call signal was replaced by GMDSS. On September 22, 1991, the international call signal was replaced by GMDSS, and SOS has been used as an international call signal for over a century. On September 22, 1991, the International Maritime Agency decided to begin abolishing the SOS signal from February next year, replacing it with new international maritime satellite electronic communications equipment, its international call system equipment has advanced functionality, when you call "GMDSS", you can hear and communicate quickly with it everywhere on the planet, to carry out emergency relief work, even in a sudden accident, as long as a button is pressed, all about the accident and location data will be automatically to the rescue agency. This is faster, more accurate and more convenient than the use of