Since the early days of radiocommunications, search and rescue has been linked to radiocommunication. Wireless radiocommunication, as evidenced by the Titanic incident, provided a means for authorities on shore to provide and coordinate aid to ships at sea, and for ships at sea to acknowledge a distress call form another ship and come to its assistance, facilitating also ship-to-shore and ship-to-ship communication. Search and rescue authorities have now been using radiocommunications for more than 100 years and its value has been evidenced in many renowned and successful SAR operations.
Since its inception, the International Maritime Organization has been instrumental in coordinating and regulating radiocommunications for search and rescue purposes. The first regulation of radiocommunication for search and rescue was implemented by the International Telecommunication Union, a sister United Nations specialized agency of the IMO, during the first International radiotelegraph convention celebrated in Berlin in 1906, which adopted the "SOS" distress signal as an international standard. The adoption of the International Convention on Maritime Search and Rescue (SAR) and the International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, by IMO strengthened the relationship between both organizations and the provision of standards and recommendations for radiocommunication in the search and rescue environment.
During the 1960s and 70s the development of satellite and digital radiocommunication technologies provided new opportunities for the development and modernization of maritime radiocommunication, particularly in relation to search and rescue. New systems and concepts such as the Emergency Position Indicating Radio Beacon (EPIRB) offered new capabilities to SAR authorities to capitalize on these developments. From 1992 to 1999, the IMO and ITU implemented a new system of SAR radiocommunication, the Global Maritime Distress and Safety System (GMDSS), which revolutionized the way distress, urgency and safety information was transmitted, coordinated and managed on a worldwide basis. It also provided standards and recommendations for shipborne radiocommunication equipment and how this radio equipment should interact with other radiocommunications equipment based on land and at sea.
The regulations and standards are provided by the conventions, resolutions and circulars that are developed through the committees of the IMO, in particular the Maritime Safety Committee (MSC) and the Sub-Committee on Navigation Communication and Search and Rescue (NCSR).