Long Range Certificate Course

A Call Sign is a unique alphanumeric identity that belongs to the vessel and acts in the same way as the registration number of a car. The Call Sign enables two vessels with the same vessel name to be identified separately. The Call Sign is also useful when the actual vessel name is difficult to understand. It can be used in an identification procedure via all means of communication .

These Call Signs are issued by the appropriate authorities in the country of registration of the vessel and can be referenced back to a database of information about the vessel and its owners etc.

If a vessel does not have its own Call Sign, the vessel owner must apply for a Call Sign at the appropriate authorities before any new communication equipment can be used on a vessel.

Each Call Sign begins with the Call Sign alphanumeric prefix that indicates nationality, e.g. prefixes allocated to the United Kingdom are 2, G, M, VP-VQ, VS, ZB-ZJ, ZN-ZO and ZQ. The prefix is usually followed by 2 or 3 alphanumeric characters.

For example, Cunard Lines Queen Mary 2 has the Call Sign W6RO.

Also, CRSs (Coast Radio Stations) using terrestrial communications, have their own Call Signs and can be contacted from any vessel's radio station.

For example, the Niton CRS in the United Kingdom has the Call Sign GNI.

All Call Sign prefixes can be found in the appendix.

All kinds of ships and CRS identifications are available on the ITU web site (www.itu.int/ITU-R/go/mars/en) in the MARS (Maritime mobile Access and Retrieval System) database. Details for each ship with a registered radio station can be found here. The database includes data about a ship’s call sign, MMSI, Inmarsat numbers and much more.