provision ciucuitale to recognize signal input, whose duration exceeds a predetermined minimum duration, especially for switching equipment innovation.

摘要

In order to determine input signals which exceed a given minimum duration, in particular call signals in teleprinter exchanges, upon occurrence of each input signal a counter for executing a counting operation is enabled, the counter output signal occurring upon reaching a given counter position serving the purpose of enabling a logic element via which communication signals (or characters or indicia) are transmitted. If the input signal which has placed the counter into operation is removed in the course of the counting operation, the counter will again return to its initial position. Through these measures, a simple differentiation of input signals having a given minimum duration and of interference pulses, having a shorter duration than the minimum duration, is possible.