For the best results of time measurements to be useful they had formerly to be announced by voice or other audible or visible signal. Parallel with the development of automatic time-measuring apparatus, there was thus a need for the development of automatic time annunciators. Audible signals have included bells, drums, gongs, rattles, musical wind instruments, guns and, latterly, electronically produced sounds, including voice recordings for use in telephone and radio systems. Audible signals were at first sounded personally by watchmen, and later by puppets called jacks, operated mechanically. For literate audiences such as those in early Chinese cities, watchmen also displayed written time announcements on banners or signboards. When jacks replaced the watchmen in the first Chinese astronomical clock towers, it was natural that by the horizontally rotating wheels of carousel jackwork the jacks should have been made to move horizontally across elevated stages like those previously used by the watchmen. The formerly widespread use of carousel jackwork for decorative purposes in European public clocks may owe its origin to this former practical function. Visible time announcements to the non-literate European public were at first possible only by the use of analogies such as a rotating statue whose hand pointed in the general direction of the sun, or an anaphoric dial carrying the sun's image behind a planispheric astrolabe rete. The European use of fixed dials with circumferential digit markings and rotating pointers, which were originally shaped like human hands, was a late development from the use of toothed wheelwork for time integration. Recently it has increasingly been replaced by written time announcements in digital displays operated mechanically, electrically or electronically.