Marine Communication Systems Used in the Maritime Industry

After hundreds of years of relying on semaphores and flags to communicate, the invention of radio dramatically changed the ability to and quality of marine communication. Continue reading to learn more about the types of communication types used in the maritime industry!

From the time advanced vessels started being used at a large scale, communication between the personnel on the vessel and others off-vessel has been a major challenge and a potential area of distress. If anything were to wrong, communicating with someone who could help was previously impossible but with advancements in technology, has become doable and easier overtime. Radio telegraphy using Morse code was the best option for a distressed ship in the early days and now, the main reliance is on radio. In the 1970s, a system was invented that allowed for vessel to vessel or vessel to shore communication was possible and eliminated the need for a radio officer on duty at all hours. These communications were possible through on board systems through shore stations and also by satellites. Most satellites need the assistance of geo-stationary posts for transmitting and receiving signals, presenting challenges in certain areas that may not reach a satellites.

The Global Maritime Distress Safety System (GMDSS) has divided the world in four sub areas for international operational requirements: A1, A2, A3 and A4. It is important to know these geographical divisions because depending on the area of operation of a particular vessel, different radio communication systems are required to be carried by the vessel. Here is information about each of these divisions:


Region A1 is approximately 25 nautical miles from shore and is under coverage of at least one VHF coast radio station in which continuous DSC alerting is available. The equipment required in this region is a VHF, a DSC and a NAVTEX receiver.


A2’s area covers about 400 nautical miles off shore. The equipment used for this region is a DSC and radio telephone (MF radio range). When going beyond one area, all equipment used in the previous areas must be included as well, therefore, the equipment required for A1 areas is needed in the A2 region as well.


A3 is the area excluding the A1 & A2 areas. Coverage in this region is within 70 degrees north and 70 degree south latitude and is within INMARSAT geostationary satellite range, where continuous alerting is available. A high frequency radio and/ or INMARSAT, a system of receiving MSI (Maritime Safety Information) as well as the systems for A1 and A2 areas.


A4 areas are outside sea areas A1, A2 and A3 and are effectively the North and South Polar Regions of 70 degree of latitude. HF radio service is required in addition to the equipment needed in areas A1, A2 and A3.

If you still have questions about marine communications, contact us today and we’ll be happy to further explain! Check out the services we offer here.

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