... Lesson 23- Radio Communication Equipment-GMDSS The radio communication equipment is the principal tool in the field of communication between a vessel and such ... marine radio communication system now is Global Maritime Distress and Safety System (GMDSS) , a new international one using improved terrestrial and satellite technology and ship-board radio systems. ... has been made by DSC, follow-up communications take place by voice on another frequency. Satellite Communications The Inmarsat satellite network provides global communications, except for the...