Universal signal generator for generating telephone system high level

Abstract

In a telephone switching facility, line circuits are arranged in groups, each including a local ringing battery bus, and a universal high level signal generator (UHLSG) for providing ringing and other high level signals to the line circuits via the local ringing bus. Each generator is responsive to address signals from a controller in the switching facility to generate selected high level signals. The UHLSG includes a switching bridge driven by a width modulated signal stream of periodically occurring pulses having assertion times suitable for developing a high level signal across a network at the output of the switching bridge. The width modulated pulses are generated from period and time signals. The period signal occurs once with each sequence in repetitively generated data byte sequences. The time signal occurs with correspondence between a selected stored data byte and an instant one of the data bytes of the sequence. A plurality of the stored data bytes are arranged in ranges in a storage circuit. One bit in the last data byte in each range causes the storage circuit's next readout to be from the beginning of a range as directed by the controller in the switching facility.