The SIS is a highly secure and protected database that is exclusively accessible to the authorised users within competent authorities, such as national border. Looking forward to meet you and the surface inspoection community again at SIS .EUROPE in Aachen, Germany. Register now and safe €. The Schengen Information System (SIS) is a highly efficient large-scale information system that supports external border control and law enforcement. The Schengen Information System (SIS) is a governmental database maintained by the European Commission. The SIS is used by twenty-six European. As of today, Croatia is connected to the Schengen Information System (SIS), the most widely used information sharing system for security and border. Communication Network platform facilitating ship-to-port, port-to-port and port-to- national authority communication, Information system for recording and issuing.