Passenger Information Systems are one of the most important elements of contemporary public transport. They significantly increase the travelling comfort for passengers, enabling them to obtain information needed to feel comfortable while travelling. The information for passengers is displayed both on-board, at railway stations, hubs, stops and on platforms. It is mainly shown by electronic information displays of various types and dimensions and audio information devices, which are controlled by specialised devices (auto computers) or directly by computers (stationary solutions) that are based on information obtained from the relevant databases. Visual information in vehicles is provided by electronic direction boards installed in the front of vehicles, on their sides, in the rear and inside. Depending on the needed resolution and the available installation place, displays with different dimensions are used. An important element of the system is on-board information monitors showing data about departures, changes, current location, adverts; entertainment content can also be displayed. Another element of the system is voice announcements. All devices are controlled by an on-board computer that can show information such as the speed, temperature outside, date, current time etc. on selected displays. Visual information is provided through electronic departure and arrival display boards at railway stations and on platforms as well. The software installed on the computer controls displaying information, providing prior determined content to the displays in the system. A temporary modification of data is possible (for example due to changes in departure time) as well as changing it permanently. At train stations, information about the timetable is required so in principle the system works offline, i.e. display boards show the lines, directions and time of next departures according to the timetable, and if the timetable is changed, data is systematically corrected by dispatchers. Like in vehicles, such visual information is completed by voice announcements.