Not since the year 1912 and the tragic loss of the RMS Titanic has there been such a radical change in the field of maritime communications. The embryo of a new global communications system commenced operation in February 1992 and will continue to be developed during the transition period leading to February 1999 when the Global Maritime Distress and Safety System becomes fully operational. This new book has been written and published at the birth of the GMDSS in order to satisfy the knowledge requirements of a new breed of radio operator and the electro-technical officer. This is a reference textbook which when read alone, or in conjunction with technical manuals, will enable the reader to fully understand both the operation and the systems of the GMDSS equipment being used.