[en] The Finnish early warning system for nuclear emergencies consists of the nation-wide automatic external dose-rate monitoring network and the control system, which is known as USVA. The monitoring network comprises of approx. 300 AAM95 central stations and substations equipped with RD-02 or RD-02L GM tubes. Stations are thoroughly inspected on a routine basis every 4-5 years. During the inspection the GM tube, battery and power adapters of the station are replaced with new ones, as is also the modem if necessary, and the alarm connections to USVA are tested. The USVA system utilizes advanced www technology (including a browser-based, easy-to-use user interface) and a network of PCs with dedicated tasks. USVA's central hardware is located at STUK. USVA began its operation in the beginning of the year 2000, replacing the older y2k incompatible system. In a routine situation, USVA collects the monitoring data once a day. The USVA is capable of connecting (via telephone lines) to eight AAM stations concurrently, and the results from the whole country are obtained in about 15 minutes. When the system receives an alarm message from the network, it sends a text message to the mobile phones defined in a separate list and starts an automatic data collection procedure at all the stations situated within a certain distance (100 km) from the alarm-causing station. (orig.)