GMDSS system

GMDSS system uses the following communication devices
DSC Radios, EPIRB, SART, NAVTEX, INMARSAT.
DSC Radios profive automatic transmitting and reciving messages. VHF DSC Radios automatically watch on channel 70. Which is a non voice channel an alarm will sound when there is an incoming call for your vessel. Or all ships call concerning urgency or safety, a distress call or a distress relay. Radio will indicate a chanel for additional communication. Such as channel 16 for distress work. Or channel 72 for ship to ship communication.