Patent GB-858779-A (GB)
Title: Apparatus for comparing encoded data
IPC: G06F7/02
Filed: 1958-05-30
Abstract: 858,779. Comparing record cards. ADDRESSOGRAPH-MULTIGRAPH CORPORATION. May 30, 1958 [June 17, 1957], No. 11048/60. Divided out of 858,778. Class 106 (1). In a business machine of the kind printing information from two groups of record cards each having coded identification data, and mixed so that cards proceed through the machine in pairs with matched serial numbers, a magnetic core comparator is provided to compare data on successive pairs of cards, there being data sensing means for reading data from the cards and recording the data in the cores, and means producing a resetting signal in time coincidence with the recording signal, but smaller and of shorter duration, for resetting any core not simultaneously receiving the recording signal, the presence on the second card of a digit not on the first card producing an output as the corresponding core is set and the absence of a first card digit on the second card producing an output signal as the core set in the first cycle is reset and control means interrupting the operation of the machine responsive to either of these signals. In the machine shown in Fig. 1, punched cards 21 consist of two groups (A and B) intermixed so as to be paired, the serial number of each pair being the same, A1, B1, A2, B2 &c. The cards are fed in turn to a pin box sensing station 26 making electrical contact through the perforations and entering identification data, e.g. the serial number in the comparator 40. Information read off the cards by a scanning device 32 passes to the printing unit 36 and is recorded on a web 41. While the first card A is in the device 32, the second card B is in the sensing device 26 and its serial number is transferred to the comparator as before. The comparator compares the new serial number with that entered from the first card and if they are identical the data from the first card is printed. If there is non-agreement, a signal from the comparator stops the machine and the operator removes these two cards and starts again with following pair. The sensing unit 26 also provides signals indicating the group A or B to which the card belongs and these are checked for correct sequence (see Specification 858,778). If the number and group sequence are correct the second card passes to the scanning device 32 to print the information thereon on the web 41. The next card then passes to the sensing unit 26 and the process repeats, serial number comparisons being made in alternate card cycles. The serial number of the card 21A, Fig. 2, is punched in columns 1-5 and a group designation 54A or 54B is punched in column 9. Other information may be carried on the remaining parts of the card. In another form, Fig. 3, the card may be punched in a combination code. Either type of card can be used in the apparatus described with minor modifications. Entry from sensing unit.-Each column of a card of the kind shown in Fig. 2 has a column of sensing pins 100-109, Fig. 5, which when the sensing unit is operated are moved towards sockets 110-119. Each odd-numbered socket is connected through to the setting windings 140-149 of a corresponding core 120-129 and the even-numbered sockets are connected through diodes to a pair of these core setting windings so that for an even number the " nine " core and one other are set. For cards of the kind shown in Fig. 3, the sensing pins would be connected directly to corresponding core setting windings. The setting windings are energized to effect recording by a thyratron 212, the anode circuit of which is first completed by cam contact 215. The thyratron is fired by the closing of cam contact 223, a magnetizing force of +2 being applied to set the core or cores in circuit. Resetting windings 170-179 are energized in common through another thyratron 225 when cam contact 236 closes shortly after setting contacts 223. This applies a magnetizing force of -1 to all cores so that any core set before the operation began is reset. The cores set by the sensing unit remain set because the setting current (+2) is still flowing and continues after the resetting current (-1) is interrupted by the opening of cam contacts 235. If the first column of the first card (Fig. 2) contains the value 3, core 123 is set and the setting produces a negative signal from output winding 203 which is passed to line 202. Any core (other than 123) set before the operation began, in being reset produces a positive output on line 204. These lines pass to an amplifier 75, Fig. 4, producing a positive output from input signals of either polarity and applies them to a gating circuit 76, which is controlled by a flip-flop circuit in the reference signal generator 79. The flip-flop is set and reset in alternate cycles so that the gate 76 is open only in the second cycle, i.e. the comparison cycle of each pair of card cycles. Comparison.-If in the second cycle the same value is sensed from the second card, the core 123 is already set and is not changed by the setting current applied to its winding, that is, the resetting current erases no information and no output is produced. Had the second card contained, for example, a " 4 " instead of " 3 " in the first column, cores 123 and 129 would have been set and a disagreement signal would have been produced from coil 209 on line 202. This would have passed through gate 76 (now open) to fire a thyratron in circuit 77 and energize relay coil 78 to stop the machine. If the value " 3 " had been merely missing in the second card, core 123 would have been reset by the resetting circuit 73, the consequent positive signal on line 204 being amplified and applied to cause circuit 77 to energize relay 78 to stop the machine as before. In a modification, a series of ten cores is provided, decimal values from the cards being entered directly instead of through code conversion diodes 161-168. Instead of using cards already intermixed, cards may be fed alternately from two hoppers and sensed by separate sensing units. The extra unit is shown at 70E in Fig. 5. The two sets of cards may then be differently coded and the group sequence check may be omitted. Instead of magnetic cores it is suggested that ferro-electric storage elements may be used, electrodes replacing the core windings.