The map below shows the coverage of maritime STDMA base stations in Sweden. Some of the base stations are already in operation but the network will fully in operation 1998/1999. The base stations are in accordance with the new IMO 4S transponder standard. For future information contact the Swedish Maritime Administration (use links "Verksamhet" + "Fud & Miljö" + AIS-Transponder") - Sjöfartsverket.