858,778. Record card machines. ADDRESSOGRAPH-MULTIGRAPH CORPORATION. May 30, 1958 [June 17, 1957], No. 17336/58. Class 106 (1). In a machine of the kind printing information from two groups A, B of record cards each having coded identification data and mixed so that the cards proceed through the machine in pairs (A1, B1, A2, B2 &c.) with matched serial numbers, the group data on successive cards is sensed and compared with the setting of a trigger, which is set and reset alternately, to check that successive cards are properly paired and the serial numbers on paired cards are sensed and compared for agreement, incorrect group sequence or lack of agreement in the serial numbers of a pair causing the machine to stop. The cards are fed in turn to a pin box sensing station 26, Fig. 1, making electrical contact through the perforations and entering the data into the comparing devices 40. Information read off the cards by a scanning device 32 passes to the printing unit 36 and, under the control of the comparator, is printed on a web 41. While the first card A1 is in the device 32 the second card Bl is in the sensing device 26 and its group designation and serial number are transferred to the comparator as before. If the group sequence is correct and the serial numbers agree, the data from the first card is printed and the second card passes to device 32 and its data is also printed. Otherwise the machine stops and the operator removes these two cards and starts again with the following pair. The serial number of the card 21A, Fig. 2, is punched in columns 1-5 and the group designation 54, A or B is punched in column 9. Other information is carried on the remaining parts of the card. In another form, Fig. 3, the card is punched in a combination code. Either type of card can be used in the apparatus with minor modifications. Checking that cards are properly paired.-The pins in block 85, Fig. 4, sensing the group designation give earth signals on lines A or B according to the group of the card sensed. These lines are connected to first and second gates 82, 83 which are enabled alternately by a trigger 79 termed "Reference signal generator." The trigger is set and reset in alternate card cycles by cam contacts. If the group sequence is correct the sensed signal always appears on the line A or B corresponding to the enabled gate 82, 83 and the output maintains coil 84 energized. Incorrect sequence causes this coil to de-energize and interrupt the operation of the machine. Serial number comparison.-The comparator now to be described forms the subject of Specification 858,779. During sensing columns of pins 100-109, Fig. 5, one for each card column, pass through perforations to engage corresponding sockets 110-119 connected either directly to the setting winding of a core 120- 129 or through diodes 161-168 to a pair of setting windings. For each digit sensed. one or two cores are set. If cards of the kind shown in Fig. 3 are used, the sensing pins would connect directly to corresponding core setting windings. The setting windings 140-149 are energized to set the selected cores by a thyratron 212, the anode circuit of which is first completed by cam-contact 215. When a cam-contact 223 closes, the thyratron fires and applies a magnetizing force of +2 to the cores in circuit. Resetting windings 170-179 are energized in common through another thyratron 225 by closure of cam-contact 235 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 is cut off by 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 pulse from output winding 203 which passes 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 either input signal which passes to a gate 76 controlled by the trigger 79. This trigger, as stated above, sets and resets in alternate card cycles so that the gate 76 is open only in the second cycle, i.e. when a " B " card is in the sensing station 26 and its serial number is to be compared with that of the " A " card in the scanning device 32. If the serial numbers agree, the core 123 is already set and is not changed when the "B" card is sensed. No information is erased by the resetting current and no output is produced. Had the "B" card contained valve " 4 " instead of " 3 " cores 123 and 129 would have been set and a disagreement signal would have appeared on line 202 from winding 209. This, passing through gate 76 would fire a thyratron in circuit 77 and energize relay coil 78 to stop the machine. Similarly, if the " 3 " hole had merely been missing, core 123 would have been reset and a signal on line 204 would again cause relay 78 to be operated. Monitor.-A circuit 80 is provided to give warning of any malfunctioning of the comparison circuit, by lighting a warning lamp. If the power supply fails the coil 81 is de-energized and gives the warning. If no data is entered from the first card, or if the amplifier fails, a thyratron ceases to conduct and the coil 81 is again de-energized to give the warning. Modifications.-Instead of using combinations of cores, ten cores may be provided for each denomination, the digits being entered directly instead of through conversion diodes 161-168. Instead of using cards already mixed, they 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 could then be differently coded and the group sequence check, which would be unnecessary, could be omitted. Instead of magnetic cores it is suggested that ferro-electric elements could be used, electrodes replacing the core windings.