GB1102499A - Improvements in or relating to a magnetic-core data storage circuit - Google Patents

Abstract

1,102,499. Circuits employing bi-stable magnetic elements; automatic exchange systems. GENERAL ELECTRIC CO. Ltd. 6 July, 1966 [6 July, 1965], No. 28582/65. Headings H3B and H4K. Read-out and automatic re-write of a magnetic core (such as core 16 in a row of twelve such cores used to switch a multiplex highway gate 8, which is switched in one out of twelve times slots depending on which one of the twelve cores is switched) is effected by a readout pulse on wire 17 followed by a half-write pulse on wire 18, output current in row wire 22 charging capacitor 26 over the emitter-base circuit of transistor 23, the potential on capacitor 26 cutting-off transistor 23 when charging current ceases so as to cause transistor 25 to conduct and supply row wire 22 with a halfwrite pulse in conjunction with the half-write pulse on wire 18, the core being thereby automatically reset. At the same time, transistor 24 conducts to open the symmetrical transistor 8 comprising the highway gate. The cores of the row are pulsed sequentially with read-out and half-write pulses in the respective time slots associated with each core. When the highway gate is idle, no core in the row is set. When the gate is required for use, as for a calling subscriber, a bias is put on wire 49 of a core 44 so that the first pulse of a train of pulses on wire 47 representing free time slots switches the core 44. Output in winding 45 of core 44 cuts-off transistor 23 to produce the consequent half-write pulse in wire 22 of the row of cores 16 so as to switch that core of the row associated with that time slot. The switched core thence forward switches the highway gate 8 in the chosen time slot. In a 100 line P.A.X., each subscriber has a row of cores such as the row 16, the column wires 17, 18 correspond to time slots in the time division cycle. To terminate a call the core 44 associated with the called subscriber is switched by a single pulse applied to winding 48 of the core in the time slot of the calling subscriber.