Selection system for telephony - uses only selectors normally necessary for direct connection with reference to exchange memory when necessary

摘要

The selection system, for telephony, has the individual networks of the selection and connection stages provide only with switching elements that are necessary for the direct construction of connections, e.g. occupation of selectors and power supply. Central memories are provided for evaluating the selection and control criteria whilst the appropriate selection and connection stage is performing its task. Switching elements are provided in the individual networks and, if necessary, in the memories. Recognition pulses are sent from selectors, at each stage and directly compared in the exchange memory. In an embodiment, the first pulse of each series is 100 ms long.