Abstract: Method and apparatus for synchronizing a clock of a telecommunication switching system. The clock of the telecommunication switching system is supplied, at least at times, with reference clock signals from a plurality of external reference clock sources. Every external reference clock source has a predetermined priority allocated to it. The supplied reference clock signals are checked for clock errors to which individual errors are allocated. For synchronization, the clock accepts an external reference clock signal dependent on the priorities allocated to the reference clock sources and dependent on the clock-error-associated error values. In an initialization, initial error values are allocated to the reference clock sources. In a re-initialization of the system, the synchronization procedure is continued from the current error values that are present at the time of the system outage.

Abstract: An imitation gem consisting of a semi shell of a transparent plastic material with concave inner and convex outer surfaces has light reflecting and light refracting facets formed on both its inner concave and outer convex surfaces. The open end of the semi shell is closed by a cover which is also provided with facets so as to further improve light reflection and refraction.