DIGSI is a familiar trade name already today. Originally launched as an MS-DOS software, DIGSI, in its third version, was developed to become a convenient tool for setting numerical protection relays under MS Windows. DIGSI 4 now is the logical innovation for easy-to-use and user-friendly setting, commissioning and operation of all SIPROTEC protection relays, whatever the version. With a PC or Notebook, you can set the relays via one of the interfaces and read out and visualize fault data. Because of its modular design, DIGSI can be used economically depending on the respective requirements. The basic version DIGSI 4 Basis already covers most standard tasks. The basic version can be extended with optional components. The basic version includes: Setting parameters and routing Human-machine interface Commissioning, controlling and testing Communication via a direct connection, via PROFIBUS-FMS or other bus systems. The complete version DIGSI 4 Professional has a greater scope than the basic version with the following additional functions: Display Editor – for creating andmodifying default and single-line diagrams shown on the display SIGRA – for visualizing and evaluating fault records DIGSI Remote – for remote controlling of SIPROTEC 4 relays via a modem connection CFC – for creating new functionality or for changing the predefined interlock conditions IEC 61850 System Configurator – for configuring and parameterizing IEC 61850 stations. This tool allows you to manage subnets, network communicators and their IP addresses and to connect the information items of different communicators.