Patent GB-786721-A (GB)
Title: Improvements in or relating to equipment for the storage of intelligence
Inventor: WRIGHT ESMOND PHILIP GOODWIN
IPC: H04L12/54
Filed: 1953-03-25
Abstract: 786,721. Digital electric calculating-apparatus and data-storage apparatus. STANDARD TELEPHONES & CABLES, Ltd. Feb. 17, 1954 [March 25, 1953], No. 8231/53. Class 106 (1). Intelligence storage equipment comprises a storage device divided into a number of defined elemental areas, means for storing elements of the intelligence in the said elemental areas, means for reading said stored elements, means for determining whether a read element is to be modified, and means for re-recording only those elements requiring, change, and for modifying those elements by re-recording in changed form in the same elemental stores, while the other elements remain in their stores unmodified without being re-recorded. Apparatus for counting and recording the number of telephone calls made by individual subscribers comprises a magnetic recording drum, reading and writing heads, a control means consisting of gating circuits of known types for deciding when to energize the writing head and a recording current generator, the writing head being spaced " behind " the reading head by the length of one recording cell. Each subscriber is allocated a section of a track of the drum and one of a set of " condition " lines, signals on which indicate calls made by the subscriber. The first cell in each section, a " supervisory " cell, is used to register the presence of a signal on a subscriber's " condition " line and prevents its being counted more than once, the remaining cells recording, in the binary scale, the total number of calls made by the subscriber. Each subscriber's " condition " line is sensed as his section on the magnetic drum is read, and the signal found on the line is compared by the control means with the signal read from the first or supervisory cell of the section. If the signal from the supervisory cell is a " 0," indicating a " cleared " condition, and if that received from the " condition " line is " 0," also indicating a cleared condition, the control means will not order the energization of the writing head during the passage of the section under it, and thus the number recorded in the section is neither re-recorded nor altered in any way and the supervisory cell retains a " 0 ". If, however, the signal from the " condition " line is not a " 0 " but a " 1 " indicating that a call is being made, the control means will then order the energization of the writing head (after a suitable delay) so that as the supervisory cell passes under the writing head it has a " 1 " written in it. The control means, in these circumstances, will also order the energization of the writing head at suitable times to reverse each of the least significant digits up to and including the first zero of the number recorded, the remaining digits being neither re-recorded or altered. Thus one is added to the number originally recorded in the section. If, when the same section is next read the subscriber has not cleared, the control means will receive # " 1 " from both the supervisory cell and the " condition " line, and will not order the energization of the writing head during the passage of the section under it. Thus the number recorded is not altered and the supervisory cell retains a " 1 ". When eventually the subscriber clears the control means will receive a " 1 " from the supervisory cell and a " 0 " from the " condition " line and will order the energization of the writing head to record a " 0 " in the supervisory cell, the number recorded being unaltered. Recording current generator. " Phase modulation " recording as described in Specification 707,634 is used. In the rest state tubes V23 and V24, Fig. 9, are passing a little current bringing their cathodes and hence the anodes of V21 to about 61 volts, tube V22A is conducting thus bringing the cathode of V21 up to - 70 volts which maintains V21 cut off, and tube V22B is cut off. Tubes V22A and V22B act as an on/off switch for the generator. When a positive signal is applied to the grid of V22B, the tube fires, V22A cuts off and the voltage across R4 begins to fall. Simultaneously with the cutting off of V22A the positive edge (- 85 volts) of a control waveform reaches the left-hand grid of V21, thus making this grid more positive than the right-hand grid, so that as the voltage across R4 falls and approaches the grid voltage, the left-hand side of V21 fires and holds its cathode at about - 84 volts. The discharge through V21 is then triggered from left to right and vice versa by the control waveform. Also simultaneously with the cutting off of V22A, a positive pulse (60 volts) is applied at eigher F4G or F4H to record a " 1 " or a " 0 " respectively. If a " 1 " is to be recorded, the left-hand side of V23 fires, the current passing through the top half of the transformer, V23 and left-hand side of V21, until the discharge through V21 is triggered to the right-hand side when V23 cuts off and the left-hand side of V24 fires, thus reversing the direction of the current in the transformer. The recording of a " 0 " is similar, the change of direction of the current in the transformer being reversed. Specifications 693,157, [Group XXXIX], 732,341, 744,352 and 786,723 also are referred to.