Normal clock
In Germany, a normal clock is a public clock that displays the normal time , which was first introduced in the German Empire in 1893 . It usually has four glass dials arranged in a cube so that it can be read from all directions .
The advent of nationwide rail traffic , whose timetables were previously based on different regional times, made it necessary to introduce a binding timetable. Initially introduced as Central European Railway Time on June 1, 1891 by the German and Austro-Hungarian railway administrations, the law on the introduction of a uniform time determination made Central European Time binding for the entire German Empire on March 12, 1893.
In the past, the time was determined locally. In Hamburg, for example, this was the job of the Hamburg observatory , which controlled several normal clocks and the telephone time announcement, or in Austria the Urania observatory in Vienna. In Berlin there was the public academy clock since 1787 , according to which the citizens set their pocket watches.
The first radio telegraphic transmissions of time signals have existed since the first decade of the 20th century. Today the normal time is provided nationwide by state and in some cases also private institutions on the Internet:
- in Germany by the time service of the Physikalisch-Technische Bundesanstalt near Braunschweig, which is also linked to the time system of the fundamental station in Wettzell and, by legal mandate, broadcasts the time via the time signal transmitter DCF77 ;
- in Austria from the atomic clocks of the BEV (Federal Office for Metrology and Surveying) in Vienna and the Graz-Lustbühel satellite station near Graz,
- in Switzerland the Federal Metrology Office in Bern with the time signal transmitter HBG (until the end of 2011).
- by phone ( time announcement )
- on the Internet with the Network Time Protocol (NTP) from one of the several thousand time servers