806,704. Digital electric calculating apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 23, 1955 [Nov. 26, 1954], No. 33592/55. Class 106 (1). [Also in Group XL (a)] A pulse-responsive gaseous discharge device comprises digit representing cathodes D0-D9, Fig. 1, and an equal number of transfer cathodes T together forming a closed glow transfer path in which alternate cathodes are digit representing, an anode A common to all the cathodes and a group of further cathodes B8, B4, B2, B1, B0 and their transfer cathodes BT, in glow transfer relation with each of the digitrepresenting cathodes D0-D9 wherein upon establishment of a glow discharge between the anode A and one of the digit cathodes D0-D9 the discharge may be transferred to other digitrepresenting cathodes along the closed glow transfer path by applying pulses to the transfer cathodes T or may be transferred to the group of further cathodes B0-B8 associated with that particular digit cathode. As shown, the digit cathodes D0-D9 each represent a decimal digit and the further cathodes B0-B8 are arranged to deliver a coded representation in a 8-4-2-1 code of the corresponding decimal digit. The digit cathodes D0-D9 are arranged with their transfer cathodes T and with inversion cathodes I for complementing in the manner described in Specification 734,903. The digit cathodes D1-8, D0, and D9 are connected to +135 volt H.T. through 47 ohm resistors by leads 11, 14 and 16 respectively. The transfer cathodes T are connected together and to a resistor network 22, Fig. 2, by a lead 20 and the inversion cathodes I are connected by a common lead 23 to the mid-point of a network 25. In each of the lateral rows the combination of the binary numbered cathodes B0-8 equivalent to the associated decimal value are commonly connected to a conductor 30 and thence through a 47 ohm resistor to +135 v. H.T. The remaining binary numbered cathodes in the row are coupled by a common lead 38 to a 47 ohm. resistor and the H.T. supply. Each of the binary transfer cathodes B.T. is coupled by a lead 31 through a 27 ohm resistor 32 to a potential divider 33, 34. In operation the circuit is reset manually or by sensing a control hole in the card to energize a relay 40 thereby completing a circuit via contacts 40a to the DO cathode. Coded information on a modified binary 8-4-2-1 code card passes between a roll 41 and a sensing brush 42 to complete a circuit in the presence of a card perforation from +61 volt H.T. lead 43, contacts C1, roll 41, brush 42, normally-open contact 45a, condenser 46 to the grid of a readin tube R which then fires. The tube R continues to fire until its anode circuit is opened by operation of contacts C3. The firing of tube R causes the screen-grid 47 of the pulse driving tube P to become more positive, thereby allowing pulses applied by operation of contacts C8 to the control grid 48 of the tube P to cause that tube to conduct for a distinct interval corresponding to each pulse to lower the potential on leads 49 and 20 at the same intervals. The read-in pulses and the corresponding negative pulses applied via lead 20 to the transfer cathodes T are 8, 4, 2 or 1 in number according to the time (8-, 4-, 2- or 1-time) in the cycle that the card perforation is sensed and the glow transfer is thereby shifted to the decimal digit cathode D corresponding to the read-in value expressed in the 8-4-2-1 code. At the end of the read-in portion of the cycle contacts C3 open and tube R and thence tube P are deionized. A similar circuit may be provided for reading in from a decimal entry record card. Alternatively information may be entered from type-wheel contacts 56 which close to apply potential to lead 60 and to contacts C2, contacts 45a (closed by operation of the relay 45 through action of the cam C4) to the grid of tube R causing it to fire and thereby allow tube P to be pulsed as before. Carry.-With each ten counter pulses applied, the glow transfers from digit cathode D9 to D0 momentarily lowering the potential on line 16 to give a negative pulse to the primary of a pulse transformer 50. The resulting positive pulse in the secondary is fed to the control grid of a carry and read-out tube C which then fires and maintains conduction through contacts 52a of read-out relay so long as cam contacts C5 are closed. Whilst firing the cathode potential rises to about +50 v. and this potential is applied by lead 54 to the counter driver tube P of the next higher order position of the accumulator. At carry time the cam contacts C7 are opened so that the voltage on grid 47 of the next higher order tube P is increased from - 100 to - 50 volts and in the presence of a carry pulse from the lower order position this grid becomes positive causing the tube to fire to pulse the counting circuit 49, 20. Immediately after carry-time contacts C5 open and tube C is de-ionized. Read-out in binary combination values.-If as a result of operations performed the glow rests on decimal digit cathode D7, it is desired to read-out this value coded as the binary combination 4-2-1. In this part of the cycle the binary read-out relay 70 and the read-out relay 80 are operated. The contact 80b raises the potential of the screen grid P from a negative to a positive value. Read-out driving pulses from cam C9 are applied via operated contacts 80a to the control grid of the pulse driving tube P causing conduction at intervals shown on C9 line in Fig. 3. As P fires the impulses are directed via lead 49, contacts 80c, and lead 31 to the binary transfer cathodes BT. The glow therefore shifts from digit cathode D7 to the corresponding transfer cathode BT and thence to B8. Succeeding pulses of contacts C9 and the timed intervals shown transfers the flow around the lateral row B8-B4-B2-B1-B0 and back to D7. At the B4, B2, and B1 cathodes pulses are developed at the 4-, 2-, and 1-times on the lead 30 and applied via closed contacts 70a to the pulse transformer 50 and thence to tube C which fires at corresponding times to energize a punch or print magnet 90. The read-out cycle is terminated by opening of contacts C6 which deionizes the tube C. Read-out of complement values.-When relay 91 is energized its contacts 91a connect the control grid of the tube S to contact C10 which when closed at the times shown in Fig. 3, apply a positive potential causing the tube to fire, lowering the potential on the line 23 to activate the inversion cathodes I for a period determined by the contact C11 in the cathode circuit of the tube S. The glow transfers, e.g. from cathode D7 to I to D2 and read-out then takes place from this complement value cathode. Read-out in decimal values.-By energizing relay 93 pulses from the read-out decimal cam contacts C12 are directed to the control grid of the pulse driving tube P causing conduction differentially at the time intervals for each index point 9-0. Starting from the cathode D7, for example, the glow is transferred to cathode D0 in three such pulses. On leaving cathode D9, a negative pulse is applied to the primary of the pulse transformer 50 and the resulting secondary pulse causes tube C to fire as the contacts C6 are closed for each index point. This energizes the print or punch magnet 90 at the 7 index time and contacts C6 then open to deionize the tube C. Subsequent pulses from contacts C2 control the return of the glow to its original position on the D7 cathode. Specifications 583,933, 675,208 and 735,750 also are referred to.