Abstract: A fail-safe interface circuit comprises at least one semiconductor switching circuit (1) with a first link terminal (2), a second link terminal (4) and a control terminal (6). To connect a first and second circuit (8, 10) attached to the first and second link terminal (2, 4), respectively, a potential difference between the control terminal (6) and one of the link terminals (2, 4) is raised above a predetermined threshold value. To avoid any flow of current from the second circuit (10) to the first circuit (8) or vice versa when the interface circuit is powered off, the maximum potential at the first and second link terminal (2,4) is actively fed back to the control terminal (6) of the semiconductor switching circuit (1).

Abstract: Time zones are handled in a telecommunication system with personal mobility and time dependent routing, particularly in a telecommunication system such as UPT (Universal Personal Telecommunication) system. The system is arranged to calculate the time difference between a time zone which is obtained from a subscriber, particularly a time zone where a subscriber permanently or temporarily is located, and a time where the routing takes place, particularly where a node is located, and to calculate the subscriber's current time by adding the time difference to the current time where the routing takes place. The time-dependent routing may include at least one time table for at least one subscriber. The time table includes at least two time periods for each time period. At least one terminal of function is defined to which the subscriber incoming traffic is intended to be routed. Corrections for daylight saving rules may be included. Menues for handling failed call setups and menues for callback are provided.

Abstract: A device and a process for measuring resonant frequency and dissipation factor of a piezoelectric resonator are presented. After exciting the resonator to oscillation, the driving power to the oscillator is turned off after the decay of the oscillation of the resonator is recorded and used to give a measure of at least one of the resonators properties, such as dissipation factor, changes in the dissipation factor, resonant frequency and changes in the resonant frequency.