ELECTRONIC TELEPHONE SWITCHING SYSTEM COMPRISING A SPEECH-PATH SWITCHING MATRIX AND TONE-CONNECTING MATRIX AND EMPLOYING ELECTRONIC CROSSPOINT SWITCHING DEVICES

摘要

ABSTRACT OF THE DISCLOSUREAn electronic telephone switching system is described havingperipheral units including a plurality of subscriber and line circuit, a plurality oftrunk and tie line circuits, at least one attendant line circuit, a plurality ofsignaling tone receivers, and a plurality of link control circuits. Switching iscarried out by a one wire speech path switching matrix and a one wire toneswitching matrix. The system is centrally controlled and includes a centralprocessing unit, program memory, a scratch pad memory and a customer memory.Information, commands and addresses are communicated between the peripheralunits and the central control and within the central control via bus lines. Thebus lines between the peripheral units and the central control transmit data withlower rise time pulses than the bus lines interconnecting the components of thecentral control. Each electronic crosspoint switch has a two terminal conductingpath and a control terminal for controlling the state of conduction of theconducting path. Different conducting path terminals of the speech path matrixand tone path matrix crosspoint switches are operated by the same peripheralline unit. The matrix coordinates to be operated are defined by polling thedifferent peripheral units connected to the coordinates in question.