Switching arrangement for telecommunication switching systems

Abstract

A telecommunication switching arrangement is described wherein each seizable switching component, i.e., a component in an idle condition, is so marked by application of an idle potential to a test point by means of a seizing circuit in that switching component. The busy condition is indicated by the absence of the aforementioned potential. The condition of the switching component is sensed by a test switching device having an internal impedance corresponding to that of a preceding switching component. The latter device accomplishes its task by completing a test and seizure circuit including the aforementioned test point. If a switching component being tested is already seized by another switching component, it will have been blocked by a blocking circuit in the other switching component. Such blocking is brought about by applying a potential differing from the idle potential from the blocking circuit via an auxiliary test switching means in the other switching component, which has an internal impedance identical to the test switching means. For seizure, the seizing circuit in each switching component is fed from a constant current generator proportioned in accordance with the number of switching components testing that switching component. The foregoing proportion is the inverse of the number of switching components testing in parallel.