Centro Internazionale Radio Medico. International Radio Medical Centre based in Rome.

A land station in the maritime mobile service providing terrestrial communications to and from ships at sea.

Communications Search and Rescue. IMO Sub–committee on Radiocommunications and Search and Rescue. Replaced by the NCSR.

Cosmicheskaya Sistyema Poiska Avariynich Sudov–Search and Rescue Satellite Aided Tracking. A satellite–aided search and rescue system. Designed to locate emergency radio beacons transmitting on the frequencies of 406.025, 406.028 and 406.037 MHz, with 121.5 MHz for homing.

General call to all stations. Frequently used in Morse transmissions, and sometimes in voice communications.

Conformance Test Report. A report certifying LRIT conformance as per SOLAS regulations.

‘from.’ Used to precede the name or identification of the calling station. Frequently used in Morse and telex transmissions.

A system in the GMDSS for transmitting distress alerts from ships and for transmitting associated acknowledgements from shore stations. It is also used for relaying distress alerts and for alerts prior to the broadcast of urgency and safety messages.

The DSC transmission of a distress alert indicates that a mobile unit (ship, aircraft or other vehicle) or person is threatened by grave and imminent danger and requests immediate assistance. It is sent using a DSC format in the bands used for terrestrial radiocommunications or a distress message format, in which case it is relayed through space stations. It is normally followed by a distress call on the associated R/T channel. The distress alert shall provide the identification of the station in distress and its position.

Data Network Identifier. A digital ID downloaded to a ship’s Inmarsat–C terminal, to permit Automated Position Reporting (i.e. to allow polling of the ship’s position).