Electronic siren Esp (an abbreviation for "Electronic siren premium") is a mass warning device, which began to manufacture in the early 90s, by the german company SiRcom GmbH. The siren belongs to a group of first electronic sirens which were ever installed in the Czech Republic through the 90s and 00s.
Esp is a straight predecessor to the ESp MAESTRO sirens made by SiRcom GmbH in cooperation with Technologie 2000. In early 00s, the siren no longer met the official requirements for electronic warning sirens issued by the Fire Rescue Service of the Czech Republic, and thus had to be replaced by a different solution.
The siren has identical appereance and specifications with SiRcom's international SiBT siren series, as well as with the 'next generation' MAESTRO series. The Esp, however generates its sound with it's hardware tone generator. It can be therefore easily distinguised when winding up and down, as the tone changes it's pitch gradually and in a noticably longer time period than the ESp MAESTRO, which uses digital recordings stored in Its MMC card.