US2142106A - Signaling system and glow lamps therefor - Google Patents

Description

Jan. 3, 1939.

H. P. BOSWAU SIGNALING SYSTEM AND GLOW LAMPS THEREFOR Filed May 9, 1934 5 Sheets-Sheet 1 l l l l l FIG. 3

x I I !NVENTOR HANS R BOSWAU ALI'TORNEY Jan. 3, 1939. H. P. BOSWAU 2,142,106

sIGNALING SYSTEM AND GLOW LAMPS THEREFOR Filed May 9, 1934 5 Sheets-Sheet 2 FIG. 4

:NVENTOR HANS P. BGSWAU ATTORNEY Jan. 3, 1939. H. P. BOSWAU 7 2,142,106

SIGNALING SYSTEM AND GLOW LAMPS THEREFOR Filed May 9, 1934 5 Sheets-Sheet 3 FIG. 5

III I l l l l l m1 FlG.6

, INVENTOR HANS P. BOSWAU .BY 5 W ATTORNEY Hv F. BCSWAU Jan. 3, 1939.

SIGNALING SYSTEM AND GLOW LAMPS THEREFOR Filed May 9, 1934 5 Sheets-$heet 4 m N mwh hhh own INVENTOR HANS P. BOSWAU ATTORNEY Jan. 3, 1939. H. P. BOSWAU 2,142,106

SIGNALING SYSTEM AND GLOW LAMPS THEREFOR Fi'led May 9, 1954 5 Sheets-Sheet 5 INVENTOR HANS P. BOSWAU ATTORNEY Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE SIGNALING SYSTEM AND GLOW LAMP THEREFOR 10 Claims.

This invention relates to signaling devices and more specifically to glow lamp indicators for selectively signaling numerals, letters or other characters or symbols.

One object of the present invention is to provide a signaling device which is capable of selectively displaying one of a plurality of characters in substantially the same space.

Another object is to provide a signaling device for selectively displaying one of a plurality of characters in which the character to be displayed is selected by means of a momentary selecting impulse whereupon the selected character is maintained on display as long as desired by the inherent characteristics of the indicator without requiring holding circuits externally of the signaling device.

A further object of the invention is to provide a control circuit for the above-mentioned signaling device which requires but one individual control wire for each of a large number of signal ng devices.

Other objects will appear in the following description taken in conjunction with the accompanying drawings in which:

Fig. 1 illustrates one embodiment of the glow lamp indicator;

Fig. 2 shows certain parts of the gaseous discharge glow indicator in exploded fashion;

Fig. 3 shows the internal circuit connections of the glow lamp indicator;

Fig. 4 shows the fundamental operating and control circuits for a plurality of glow lamp indicators;

Fig. 5 shows the internal circuit connections of an alternative embodiment of the glow lamp indicator;

Fig. 6 shows the fundamental operating and control circuits for the alternative embodiment;

Fig. 7 shows an application of the glow lamp ind cator and control circuit to a stock quotation system, illustrating the selecting equipment required on a subscriber's premises; and

F g. 8 shows the equipment required for one stock in the stock quotation system.

In the well-known space discharge devices or glow lamps. a pair of metallic electrodes are sealed with n a glass bulb filled with neon, mercury, sodium or other suitable gases at a definite very 50 lea pressure. When a unidirectional (direct current) potential is applied to the electrodes and gradually increased, the glow discharge will set in at a certain definite potential called an igniting potential. The luminous glow discharge is produced by negative electrons and positive gas ions and takes place within a certain small distance from the exposed surface of the cathode or negative electrode, which appears to be surrounded or coated with a thin film of light. This film of light follows the contours of the cathode surface in all details.

When the potential is further increased, the glow discharge becomes somewhat brighter. When the potential is gradually reduced, the glow discharge is maintained down to a potential considerably below the igniting potential, until at a certain definite minimum potential the discharge ceases.

If an intermediate potential somewhere between the igniting and minimum potential is applied to the electrodes, there will be no glow discharge, but if the potential is momentarily raised to or above the igniting potential and thereafter reduced to the intermediate potential, the discharge will be started by the igniting potential and thereafter be maintained by the intermediate potential until the potential is reduced to or below the minimum potential. This characteristic of the glow lamp makes it possible to control the starting and stopping of the glow discharge by means of brief momentary impulses of high and low potentials, with the lamp normally connected to an intermediate potential.

Thus, the glow lamp may be lighted by the application of an igniting impulse and thereafter remains lit, until the potential is reduced momentarily below the minimum potential. This feature offers a means to control glow lamps without external holding relays or other means for keeping the lamp circuit closed when it is desired to have the lamp glow.

The fact that the exposed parts of the cathode of a glow lamp are entirely surrounded by a thin film of luminous discharge may be utilized to display any desired character by means of properly shaped cathodes. A cathode consisting of a wire shaped in the form of the numeral 1 will, when ignited, produce a luminous outline of the numeral 1, and similarly any other desiredcharacter may be formed.

In the present invention these two characteristics of the glow lamps are utilized as follows: In Fig. 1 the glass bulb I0! is filled with a suitable gas, such as neon, at the required pressure. The glass foot I02 has fused into it a number of supports I03, which hold the disk assembly I04 near the forward part of the bulb. The disk assembly I 04 consists of eleven very thin disks of glass, stacked one behind the other with a small separation between adjacent disks. In the in terstices between the disks the electrodes are arranged in the shape of line metal wires, the cathodes being shaped in the form of the ten numerals 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0, while the anodes are short pieces of wire near the lower part of each cathode. The anodes do not glow, and those parts of the cathode wires which are not desired to glow are covered by a suitable insulation, such as enamel.

The bulb is mounted in a base I provided with external terminals I. The connections from the terminals to the electrodes are made by means of connecting wires Ill and I", and are carried through the glass foot I02 in a wellknown manner by means of short connectors I01 made of metal having the same coefliclent of expansion as glass.

Fig. 2 shows the disk assembly ill in an exploded view to illustrate the ten cathodes Ill and ten anodes 205. Each of ten glass disks 203 has the wires 2M and 20! forming the electrodes cemented to its surface in a suitable manner. The lead out wires, such as 202, which are not desired to glow, are covered with suitable insulation.

These ten disks with an additional front cover disk 204 are then stacked one upon the other, the wire electrodes serving to separate the disks from each other so as to permit access of the gas filling to the electrodes. After the disks are assembled, the interstices between them may be sealed in a suitable manner around the periphery to prevent interference from one electrode to another. A small'aperture may be left at one point of the periphery by leaving out the sealing operation at this point, to provide communication with the main gas chamber formed by the glass bulb I III.

When the bulb llll is subsequently exhausted and then filled with gas at the proper pressure, the exhausting and filling process extends through this communicating aperture to the ten gas chambers formed by the eleven glass disks 203 and 204. The communicating aperture may be filled with a suitable sealing material which permits the air and gas to permeate during the exhausting and filling operation. After these operations are completed and the bulb Ill is sealed oil, the sealing material in the communieating aperture may be rendered impervious to the gas by suitable procedures, such as heating by means of electronic bombardment, for the purpose of completely sealing the ten gas chambers from each other and from the main gas chamber formed by the bulb II.

The entire disk assembly is very thin. If, for example, each glass disk is 0.008 inch thick and the electrode wires have a diameter of 0.002 inch, the assembly I04 is altogether only 0.108 inch thick. As a result, the rearmost cathode 0, when glowing, will be easily discernible through the ten disks in front, and the other nine cathodes in the shape of the numerals l to 9 will not obscure the glow surrounding the cathode 0 to a noticeable degree, inasmuch as the cathodes are only 0.002 inch in diameter while the glow discharge appearing on both sides oi the glowing cathode is approximately ,5 inch wide.

Viewed from the front of the bulb, therefore, any one of the ten cathodes, when glowing, will appear in approximately the same place. In this manner, any one of the ten numerals may be displayed by causing the corresponding cathode to glow.

Fig. 3 shows the connections inside the bulb, "I being the ten cathodes, connected to ten terminals "I, the ten anodes Ill being connected to terminal I. A resistance 8" may also be mounted in the base I and connected to terminals 304 and I".

It will be obvious iron the foregoing description of the characteristics of the glow lamp that if a potential between the minimum and igniting potential is applied between the common anode and all ten cathodes, any one o! the ten numerals may be displayed by the momentary application of the igniting potential to the corresponding cathode. This initiates the glow discharge at the selected cathode which is then maintained by the intermediate potential after the igniting potential is removed while all other cathodes will remain dark, since the discharge of these cathodes had not been initiated by the application of the igniting potential. To extinguish the glowing cathode, the potential of this cathode, or of all cathodes, is momentarily reduced to a value below the minimum potential or to zero. Thereafter, any other cathode may be caused to glow by momentarily applying to it the igniting potential.

Thus the described glow lamp may be used to and that the construction is not limited to ten :3.

characters, but permits the use of a larger or smaller number of diflerent characters.

In the arrangement described above, one control wire is required for each cathode or character to be displayed. Where a large number of glow lamp indicators are required to display the desired information, the number of control wires becomes considerable, and to reduce the necessary number of control wires to one individual wire per glow lamp indicator and a number of common control wires corresponding to the number of characters in each lamp, the invention makes use of the control circuit shown in Fig. 4.

In this circuit all cathodes corresponding to the numeral 1 are connected to the common wire I and similarly the cathodes 2 to 9 and I are connected to common wires 4.2 to 408 and 4", respectively. Each of these ten wires is connected over a break contact of the ten number keys 4 to 420 to the negative pole of the battery 42!, which supplies the intermediate potential. The anodes of each of the glow lamps are connected through resistances I to 434 to the positive pole of the battery 4. In this manner intermediate potential is applied to all cathodes.

If it is desired to light, for example, numeral 1 of glow lamp I, the key I associated with this lamp is operated, thereupon number key 4 and then the common sending key 424. when key "I is operated, all ten pairs of electrodes of glow lamp 4 are short-circuited from the anodes of lamp I over make contact of key "I, break contact of key 424, break contacts oi the ten keys 4 to 42., wires 4" to 4", to the ten cathodes of lamp 4. This has no result if all lamps are dark and will not aifect any of the other lamps, such as 442, 443, 444, etc., which all remain connected to battery 4. Upon operation of key 4, cathodes I of all lamps 44!, 442, etc. are disconnected from the negative pole of battery 42I at the break contact of key 4 and connected over the make contact of this key and rectifier 425 to the negative pole of battery 42L This has no eilect upon any of the lamps, as the cathodes remain connected to the negative pole of battery 42! and the rectifier 425 inserted in the circuit does not change the potential.

When the key 424 is operated, auxiliary battery 423 is connected in parallel with rectifier 425, thus in effect placing battery 423 in series with battery 42! and thereby raising the potential on cathodes I on wire 40! to a value higher than the intermediate potential but not quite high enough to ignite the cathodes. This circuit is traced from cathodes I of glow lamps 44! to 444 over wire 40!, make contact of operated key 4! I, thence in parallel through rectifier 425 and through upper make contact of key 424 and battery 423 to battery 42 I, through battery 42! and resistances 43! to 434 to the anodes of glow lamps 44! to 444. Rectifier 425 serves to prevent short circuiting battery 423. At the same time the short-circuit on lamp 44! is opened at the break contact of key 424 and auxiliary battery 422 is connected in series with battery 42! over key 45! to lamp 44! only. This circuit is traced from cathode I of glow lamp 44! over wire 40!, make contact of operated key 4| I, thence in parallel through rectifier 425 and through upper make contact of key 424 and battery 423 to battery 42!, through battery 42!, and thence in parallel through resistance 43! and through battery 422, lower make contact of key 424 wire 46! and make contact of key 45! to the anodes of glow lamp 44!. Battery 422 is of such potential that its addition to the potential of battery 42! is not quite sufficient to reach the igniting potential. At cathode I of lamp 44!, however, the potential applied is that of batteries 42!, 422 and 423 added together and this is higher than the igniting potential, so that cathode of lamp 44! is ignited. Cathodes I of all other lamps have impressed upon them the potential of battery 42! plus that of battery 423, which remains below the igniting potential, so that none of these cathodes will begin to glow. Cathodes 2 to 9 and of lamp 44! have impressed upon them the potential of battery 42! plus that of battery 422, which is below the igniting potential, so that no one of these cathodes will begin to glow. The only cathode where the igniting potential is reached is cathode I of lamp 44! where the additional potentials of both auxiliary batteries 422 and 423 are added to that of battery 42!. Consequently cathode I of lamp 44! is the only one that will light.

After this cathode is lighted, first key 45! and then keys 4!! and 424 are released. The release of key 45! removes the additional potential of battery 422 from lamp 44!, but cathode I of this lamp remains illuminated through batteries 42! and 423 in series. This circuit is the same as that described above for connecting battery 423 in series with battery 42!. are released, auxiliary battery 423 is also removed from the circuit, but cathode I of lamp 44! remains lit, inasmuch as the potential of battery 42! is above the minimum potential and is sufllcient to maintain the glow discharge. The circuit for cathode I of lamp 44! is traced from this cathode over wire 40!, normally closed contact of key 4! I, battery 42!, resistance 43! to the anodes of lamp 44!. The control circuit is now back to normal and cathode I of lamp 44! is lit.

If it is desired to extinguish cathode I of lamp 44! and to light cathode 2 of this lamp in its stead, first key 45! is operated and then keys 4 l2 and 424. The operation of key 45!, as described above, short-circuits lamp 44!, thereby extinguishing cathode I of this lamp. The subsequent operation of keys 4I2 and 424 thereupon initiates When keys 4!! and 424 the discharge of cathode 2 of lamp 44! in the above described manner. Thus it will be evident that any desired cathode of any of the lamps may be lighted at will by means of the operation of the proper keys. The operation of the common keys has no effect upon any lamp whose individual key, such as 45!, 452, etc., is not operated. In the case described above, it is to be noticed that the potential of battery 42! plus that of battery 423 is impressed upon control wire 40! when keys 4!! and 424 are operated. This potential is still below the igniting potential, and cathodes I of all lamps where this cathode is dark, remain dark. In those lamps where this cathode happens to be lit, the additional potential will cause a slight brightening of the glow, but has no other effect upon their operation. It will be noticed that keys 4! to 420 are provided with make-before-break contacts, so that the operation of these keys never interrupts the battery circuit.

It is possible to control several lamps at the same time by operating several of the keys 45!, 452 etc. before the keys 4!! to 420 and 424 are operated. In this case the same numeral will be displayed on all the lamps which are controlled simultaneously. It is not possible to light erroneously more than one cathode in each lamp inas much as the value of the series resistances 43!, 432 etc. is such that the combined voltage drop occasioned by two or more cathodes glowing at the same time brings the potential across the electrodes to' a value below the minimum potential. In such a case all the cathodes of the lamp in question are extinguished as soon as the sending keys are released.

It will be obvious that this method of control can be applied to an unlimited number of lamps. Besides the common control wires 40! to M0, the number keys 4!! to 42 I, the sending key 424, the batteries 42!, 422 and 423, and the rectifier 425, each lamp requires one individual control key, such as 45!, 452, etc., one resistance such as 43!, 432, etc., and one individual control wire such as 46!, 462, etc. It will be obvious to those skilled in the art that relay contacts may be substituted for the keys without affecting the method of operation.

In the well-known grid glow lamp a third electrode, the so-called grid, is interposed between the cathode and anode. When a negative bias potential is applied to this grid, the result is an increase of the potential required for igniting the discharge. When the grid bias is gradually reduced, the discharge sets in at a certain definite value. Thereafter the grid bias may be increased again without affecting the discharge, since the negative grid attracts a space charge of positive ions from the glow discharge, which effectively neutralizes the grid. This principle may also be used for the present invention. Fig. shows the internal circuit of a glow lamp indicator using this principle. The mechanical construction is substantially the same as illustrated in Figs. 1 and 2. Electrically, however, all cathodes 50I are connected to a common terminal 502, while the anodes 503 are connected to terminal 504. Ten grids 505 are interposed between the cathodes and anodes and connected individually to ten terminals 501. A potential below the igniting value impressed upon terminals 502 and 504 will not cause the discharge to start. The ten grids 505 are normally connected to a negative grid bias potential. To start the discharge at any one of the cathodes, its corresponding grid bias is lowered to a point where the discharge will set in.

Thereafter, the grid bias may be returned to its normal value without affecting the discharge that has set in. In the actual construction of the glow lamp indicator, the grids may take the form of a short piece of wire interposed between the cathodes and anodes.

The control circuit shown in Fig. 6 for the grid glow lamp indicator is similar in principle to that shown in Fig. 4 for the ordinary glow lamp indicator, the only changes being those made necessary by the characteristics of the grid control principle. The cathodes of all lamps I, 642, etc. are connected to the negative pole of battery SH and the anodes through individual resistances Bill, 632 etc. to the positive pole of the same battery.

Battery 62I supplies a potential suflicient to maintain the glow discharge after it has once set in, but insufiicient to initiate the glow'discharge."

Grids I of all lamps I, 642, etc. are connected to the common control lead 6M, and the other grids 2 to 9 and II similarly to control wires 602 to GIO. All ten wires GM to 6H! are connected through break contacts of the associated keys ii I to 620 to point 625 of the main battery 62I, this point being near the negative pole and thus impressing a negative grid bias upon all grids.

In order to light cathode I of lamp I, for example, first the control key BSI associated with this lamp is operated and then the common control key SI I associated with grids I and the sending key 624. The operation of key 65I short-circuits the lamp 6 from the anodes over make contact of key 65I, individual control lead 66!, break contact of key 624 to the cathodes. This short-circuit extinguishes any cathode of lamp 63I that may be lit at this time without affecting any of the other lamps. When key 6H is operated, the grid bias on grids I of all lamps 6, 642, etc. is disconnected from point 625 near the negative pole of the main battery 62I and connected to point 623 which is nearer the positive pole of this battery.

Keys ii I to 620 are provided with make-beforebreak contacts to prevent interruptions of the battery circuit. Rectifier 626 serves to prevent short-circuits between points 523 and 525 during the time while the make and break contacts of keys 6| I to 620 are both closed.

Although the operation of key GII changes the bias on grids I of all lamps, this change does not affect any of the lamps as long as their individual control keys BSI etc. are in the normal position. In some of these lamps cathode I may be dark and in others it may be glowing, depending upon preceding control operations. In the lamps whose cathode I is dark, this cathode will remain dark, because the voltage of the main battery MI is insufficient to start a discharge even with reduced grid bias. where cathode I is glowing, the discharge is not afiected by changes in grid bias, so that these cathodes will continue to glow.

When key 624 is operated, the short-circuit on lamp 6 is opened at the break contact of key 624 and the anodes of lamp I are connected to the auxiliary battery 622 which is in series with the main battery MI and raises the potential on the ten pairs of electrodes in lamp I to a value which in itself is not sufficient to initiate the discharge on those electrodes whose grid has the normal negative grid bias from point 625 of the main battery. However, where the increased potential on the anodes and the reduced grid bias On the other hand, in the lamps from point 023 of the main battery come together, that is, at anode I, the combined effect of the increased potential on the lamp and the lowered grid bias is to cause the discharge to set in. As a result, the discharge sets in at cathode I of lamp I.

When key "I is released, the increased potential on lamp I is removed and this lamp now receives its potential over resistance "I from the main battery 62 I. This potential is sufficient to maintain the discharge irrespective of the value of the grid bias. The release of keys "I and 625, whereby the grid bias is restored to its normal value, therefore has no further effect upon the discharge at cathode I of lamp I.

In a similar manner ai. other numerals in any of the lamps may be displayed at will by proper operation of the COIltlOi keys. if it is desired to extinguish a lamp without lighting a new number, it is only necessary to operate the associated individual control key, such as I, 452, etc. or "I, 652 etc., whereby the associated lamp is shortcircuited in Figs. 4 and 6.

Figs. 7 and 8 illustrate the application of the new glow lamp indicator to a stock quotation system, although it will be understood that the principle of this invention is by no means limited to stock quotation systems, but may be used to advantage in any system where it is necessary to display information by numerals, letters or any other characters or symbols. It will also be understood that the new glow lamp indicator may be constructed in any desired shape or size up to the largest dimensions. The circuit shown in Figs. 7 and 8 makes use of the method of control shown in Fig. 4, but it will be understood that it may be modified to the method of control shown in Fig. 6 by any one skilled in the art.

The stock quotation system illustrated is arranged for a maximum of 1500 different stocks, giving for each stock the hundreds, tens and units digits and fractions (in eighths) of the closing price of the preceding day, and the tens and units digits and fractions (in eighths) of the opening, highest, lowest and last price of the current day. It is capable of transmitting two quotations per second or 120 quotations per minute with the customary speed of telegraphic transmission over the line. Contrary to well-known stock quotation systems in use at the present time, where the speed of transmission is governed chiefly by the time required for sending the news sary number of impulses into the mechanical indicators, the stock quotation system disclosed herein is limited in speed only by the transmission over the line, the local control of the new glow lamp indicators being accomplished practically instantaneously without recourse to a varying number of impulses.

In the system shown, first the desired stock is selected by transmitting the hundreds, tens and units digits identifying the stock, next a code is transmitted to select the range, i. e. the close, open, high, low or last price or any desired combination thereof, and finally the tens and units digits and the fractions of the price are transmitted. The transmission is performed on the startstop principle by means of a four unit code, that is, each digit is represented by four line impulse spaces and the selected number is identified by the absence, called marking current", or presence, called spacing current, of line current during each of these four spaces. The codes used are shown in the following table, but it will be understood that any other combination of four-unit codes may be employed. In the table a dash represents a spacing pulse, while a marking pulse is indicated by a numeral designating which of the four impulse spaces is occupied by the marking pulse.

Before going into a detailed description of the sequential operations which occur in a code transmission, the various apparatus used in my invention and their functions will be described.

The transmitter shown diagrammatically at 155 in Figure 7 consists essentially of a battery I54 and a transmitting contact I53 actuated by a motor driven tape or key board and distributor (not shown) for transmitting code combinations of impulse conditions to select a stock at a remote receiving point and thereafter indicate its quotation thereat. Any one of a number of well known types of transmitters, such as a key or tape operated, may be used, for example a transmitter of the type shown in the patent to Kleinschmidt, No. 2,010,158, dated August 6, 1935, but inasmuch as they do not form a part of this invention, no specific illustration thereof need be given.

The transmitter I55 is connected over the line I80, broken to illustrate that it extends to a remote point, where the receiving apparatus comprising my novel stock quotation system is located. Connected at the receiving end in this line is a relay I52 which is arranged to operate its armature in response to the received code combination of impulse conditions. To transmit the code combination, the transmitter distributor is released for a cycle of operations and a start impulse is transmitted which functions to release a clutch (not shown) on the receiver, releasing the receiving distributor for a cycle of operations. The transmitting and receiving distributors rotate in synchronism with each other through one revolution. Thereafter the two distributors are stopped at a-normal nonoperating position by the disengagement of the clutch and remain at rest until the next transmitting impulse.

The line relay I52, located at the receiving end, operates in response to the start impulse to control the operation of the clutch magnet 15I. Clutch magnet II upon its energization, releases the clutch referred to above to permit the distributor brushes to wipe over the rings I56, I51, I58 and I59 to be rotated by their motor through a single revolution in a manner well-known in the art.

During the rotation of the brushes, code combinations of impulses are received in synchronism with the brushes so that a new impulse condition is received as the brushes engage successive segments, each code combination comprising four impulse conditions as described above, although either more or less impulse conditions may be used for each code combination, depending upon the number of selections to be made, as will be well understood by those skilled in the art.

The first code combination received is arranged to make a "hundreds selection. The next code combination received is arranged to make a "tens" selection, and the last, a units selection.

This completes the selection of the stock whose quotation is to be given and there then follows a code combination indicating the range or type of selection such as last, low, high, etc. Following this, further code combinations are received to indicate the actual quotation of the stock and range.

The code combinations are all received over the segments of distributor ring I56. Thus the first code combination in making the hundreds" selection is received while the distributor brush moves over the segments 2 to 5 of ring 156, to the left of the segment on which the brush is shown at rest. The selection set-up on the relays IZI-Ifl is thereupon held locked by reason of the brush of ring 15! being on a conducting portion at this time.

Immediately after the receipt of the first code combination, the brush I60 moves from an insulating portion to a conducting segment on the ring I59 and energizes the relay IBI. The particular selection set-up on the relays HI-I24 is thus transferred to a particular one of the hundreds group selecting relay I62. Although only one hundreds selection relay I62 is shown, it will be obvious that there may be as many of these hundreds selection relays as the possible code combinations set up by the relays I2I--I24.

While this transfer for making the hundreds group selection takes place, the brush, wiping over the segments of the distributor ring I56, has also passed over the first two segments of the next code combination, namely, segments 6 and I, and as the brush F60 moves into engagement with the insulating segment I60, the remaining two impulses of the second code are received for selectively energizing relays I3l to I34, which function similar to the relays I2 I--I24 to receive and relay the received codes. The two sets of code-receiving relays HI-I24 and Till-I34 provide an overlap to insure full use oi line time but, as shown, only a partial overlap is necessary, due to the fact that the actual set-up on the selecting relays consumes time,

necessitating a partial overlap.

Thus, prior to the end of the receipt of the second code combination, the brush wiping over distributor 'I5I moves into engagement with an insulating segment opening the locking circuits of relays Ill-I24 so that these relays are restored and prepared to receive a new code combination. It will be noted that this occurs immediately after the brush 160 has transferred the set-up of relays I2II2t to select the hundreds group relay I62.

During the receipt of the second code combination, the brush of ring I58 is in engagement with the conducting portion of the ring for providing a locking circuit for the selectively energized relays BI-I34.

Immediately after the receipt of the last of these impulses of the second code combination, the brush I60 moves into engagement with a conducting segment on the ring I59 and provides an energizing circuit for the transfer relay relays i3i|34 to select the tens" group selecting relay 165. Although one such tens selecting relay is shown, it will be obvious that the number of such selecting relays may again be equal to the number of selections that may be made by relays 13I'|34 times the number of hundreds selection relays. Moreover, although the transfer relay 163 is shown as providing connections only to the "hundreds relay 162, it will be obvious that multiple connections are provided through this relay to all the other "hundreds" group relays.

While this transfer takes place, the third code combination is being received over the distributor segment I58. to selectively energize relays Hi-I24 in accordance with a units" selection. During this time the brush of ring I51 is on a conducting segment so as to provide a locking circuit for these relays, and during the latter half of this interval the brush of ring 158 is on an insulating portion for releasingthe lock of relays 13i'|3l which by this time have transmitted their setting to the tens" selecting relay.

The third code combination is received while the brush of distributor 156 is passing over segments iii to Hi. Following the receipt of the third code combination which makes 8. units selection, a circuit is completed over the armatures of relays i2l12l and through an armature of the tens relay I65 to the relay "II which controls the glow lamps of the selected stock. This occurs following the energization of the transfer relay 164 which is energized immediately after the receipt of the code combination when brush I60 moves into engagement with the fourth conducting segment of ring I59. Here again, although circuits are shown extending from the armatures of relays IN to the tens relay 165, it'will be understood that multiple circuits are provided to all the other tens relays employed in my system.

Following the selection of the relay I individual to the particular stock quotation to be quoted, it is necessary to transmit a further code combination to determine which of the ranges of quotations is to be transmitted. This is accomplished while the distributor brush is passing over the fourth group of distributor segments H to i! distributor ring 156. Relays ill-1 are selectively energized during this interval and selectively control the energization of relays HS-I20 which are individual to the particular range. Relays HS-I20 over their armatures, control energizing circuits for the glow lamps individual to the respective ranges such as close, open, high, low, etc.

At thispoint not only has an individual stock been selected, but the particular glow lamps for the range which is to be transmitted have also been selected. There follow code combinations to indicate the quotation of the selected stock and range. This occurs while the brush of distributor I56 passes over the fifth, sixth and seventh group of segments, comprising the segments l8 to II, 22 to 25, and 28 to 29.

As the brush passes over the segments II to 20, relays Iii to 134 are selectively energized in accordance with the tens quotation of the selected stock. At this time a locking circuit is provided in these relays over the brush of distributor 158 which is passing over a conducting portion thereof. Immediately following the receipt of the code, brush I moves into engagement with the next to the last conducting segment of ring III and completes an energizing circuit for the relay 7" which transfers the selective set-up of the relays Ill-Ill to select a relay Ill-Ill. There are ten such relays to enable the selection of the numerals 1-9 and 0.

The next succeeding code selectively energizes relays III-I24 as the brush oi distributor 1 passes over the segments 22 to 2!. Immediately following this selection, the distributor brush I60 passes into engagement with the last conducting segment of the ring 1", completing an energizing circuit for the transfer relay I01 which again transfers the set-up of the relays HI-124 to the relays Ill'l|0. Following the energization of these relays and just before the distributor is brought to rest at normal position, relay H4 is energized which provides a multiple energizing circuit for relay 1 to make the final transfer of the fractions selection.

When the code for the tens" quotationis received, relay Ill being at this time de-energized, the glow lamp for the "tens quotation of the particular selected stock and of the particular range is energized over the uppermost armature of the selected relays I l8-I2ll. When the units quotation code is received, the circuit for the units" glow lamp is energized over the middle armature of the selected relays HS-120 and finally, when the fractions" quotation code is received, the fractions" glow lamp of the selected stock and range is energized over the lowermost armatures of the selected relays HO-120, and in each instance the numeral in the glow lamp selected to illuminate is determined by the particular unit relays Ill-III which is energized.

As shown, the armature of the relay HI extends only to one relay because this is the range relay for the hundreds digit appearing in the close position only. The range code hundreds- No. 14-marking pulses 23lselects range relay H5 which controls the lighting of the hundreds lamp in the close position. For purposes of simplicity the hundreds lamp in the other positions is omitted.

A detailed description of the operation will now follow.

Normally the line relay "2 at the receiver is energized over the line, sending contact 153 and battery IN. When a quotation is to be transmitted, the sender opens the contact I93 momentarily for the purpose of starting the receiving distributor. Line relay I52 releases and energizes the clutch III over the first segment of distributor ring In and its associated brush, and

break contact of line relay III. The distributor rings I56 to I58 are shown developed as straight lines, but it will be understood that they are actually arranged in circular form so that the last segment is adjacent to the first.

when clutch "I is energized, it couples the driving motor (not shown) with the brushes 1 which thereupon rotate over the distributor rings 18. to ISO in synchronism with the sender until one revolution is completed. As the top brush passes oi! the first segment of distributor ring III, the circuit of clutch "I is opened, but the clutch is kept engaged by mechanical means until one revolution is completed.

For purposes of illustration it will beassumed in the following that stock No. 1516 is to be selected. Hundreds code I I as shown above, is represented by marking current on the line during all four impulse spaces. Accordingly, line relay ii! is, deenergized while the brushes pass-over the next four segments of distributor ring I56. As 5 the brush passes over the first of these segments with the line relay I52 tie-energized, a circuit is closed for relay I21 over the segment of ring 156, its associated brush and break contact of line relay I52. Relay I21 operates over this circuit and looks over its own make contact. distributor ring 151 and its associated brush. The line relay being de-energized during the next three impulse spaces, relays 122, I23 and I24 are similarly operated and locked.

Relays 121 to I24 and also I31 to I34 are so adjusted that their locking contact closes first before any of the other contacts are actuated.

Thus it is not necessary that these relays are completely operated during the brief 7 interval while the brush passes over the associated segment, it being sufllcient to close the locking contact whereupon the relay is fully operated over the holding circuit. The relay 121 with the lar est number of contacts is on the first segment, so that it may fully operate during the next three segments.

While the transmitter sends the next four impulse spaces for the tens digit of the stock number, the selection registered on the four relays -I21 to I24 is translated into the operation of the corresponding hundreds selection relay in the following manner:

As the brushes pass from the last of the hundreds selection segments, a circuit is closed for relay 161 over a segment of distributor ring 159. Relay I61 operates, in turn closing a circuit for one of the hundreds selection relays, depending upon the position of the four register relays 121 to I24. In the present case, all four of these relays are operated, closing a circuit for hundreds selection relay 162 over make contact of relay I61, and make contacts of relays 121, I22, I23 and 124. Relay I62 operates and looks over its own make contact and break contact of relay I14.

Only one hundreds selection relay 162 is shown, but it will be obvious that in reality one such relay is provided for every hundred stocks, or a total of for 1500 stocks, each being connected to one of the 15 contacts of relay I61. If a code other than No. 15 is transmitted, the four relays 121 to I24 will be operated in a different combination, resulting in the operation of a different hundreds selection relay when relay I61 is energized.

Two segments after the hundreds code is transmitted, the brushes of distributor rings I51 and I59 pass oif their segments with the result that the holding circuit for relays 121 to I24 is opened at ring 151 and the circuit of relay I61 at ring I59. All these relays release.

Meanwhile the top brush has been passing over the tens segments of distributor ring 156, causing the registration of the selected tens digit upon the four relays 131 to 134, overlapping in part, the time during which the hundreds relay 121 to 124 are still locked.

In the present case, the tens digit is 1, corresponding to marking current on the line during the first of the four impulse spaces only. As a result, the line relay I52 is tie-energized while the brush passes the first of the tens segments, but energized while the brush passes over the next three segments. Consequently relay 131 will be operated, while relays I32, I33 and I34 remain tie-energized. Relay I31 looks over its own make contact, break contact of relay I14 and distributor ring I58.

After the tens selection line impulses are completed, a circuit is closed over distributor ring I59 for relay-I63, which connects the contacts oi relays 131 to I34 to the windings of the tens selection relays, resulting in the operation of the proper one of these relays. In the present example, the circuit closed by the register relays I31 to I34 leads to tens selection relay 165, from winding of 165 over make contact of hundreds selection relay I62, make contact of relay I63, make contact of relay 131 and break contacts of relays I32, I33 and I34. Relay '165 locks over its own make contact and break contact of relay 114. Two segments later, the circuit of relay I63 and the locking circuits of relays I31 to 134 are opened at distributor ring 156 and I59, causing these relays to release.

Only one tens selection relay 165 is shown, but it will be obvious that in practice one such relay is provided for every ten stocks, or a total of 1-50 relays for 1500 stocks. Which of these relays operates depends upon the previously energized hundreds selection relay and upon the position of register relays I31 to I34.

Meanwhile, in partial overlapping time relation, the top brush has been passing over the next four segments of distributor ring I56, which are connected to register relays 121 to 124. As a result the units stock selection digit is registered on these four relays. In the present example the units digit is 6, represented by marking current I contacts of relays I and I64, break contact of relay I21, make contacts of relays I22 and I23, and break contact of, relay I24. Relay 8511 looks over its own make contact and break contact of relay I14. Only one stock selection relay 850 is shown, but it will be obvious that one such relay is provided for each stock whose prices are to be indicated. Which of these stock selection relays operates depends upon the previously operated hundreds and tens selection relay and the position of register relays 121 to I24.

If desired, the number of stocks may be increased to 15 15 15:3375, without increasing the transmitting time. To accomplish this, relays I31I34 are equipped with the same contact arrangement as relays I21 to I24 and five make contacts are added to relays I62, I63, 164 and 165,

and the number of tens selection relays is raised to 225.

Two segments later, on distributor ring 156, the circuit of relay I64 and the holding circuit of relays I21 to I24 are opened at distributor rings '15! and I59, causing these relays to release.

Meanwhile and in partial time overlapping relation, the top brush has been passing over the four range selection segments of distributor ring I56, registering the desired range. The range determines'upon which indicators the subsequent price quotation is to be registered, that is, either close, open, high, low or last price. In addition, there are the ranges high and last together used when the last price also sets a new high, similarly low and last together, when the last price also sets a new low, unison used to set the first price of the day, when open, high, low and last are obviously the same, hundreds used to set the hundreds digit of the closing price of the preceding day, which is not repeated on the other ranges open, high, low and last. A further range is wipe-out which sets all indicators of one stock at the same time, used to restore the indicators to normal at the beginning of the day. The codes used for these various ranges are as follows:

Code No. Markingpulses l l-- 2 -2-- 4 --3- 8 ---4 6 -23- l4 -234 4 i2--- 5 l-3. 15 1234 Wipe-out... 10 -2-4 For purposes of illustration it will be assumed in the following that the range low and last is to be transmitted. This code calls for marking current during the first and second segment, resulting in the operation of relays 1 and 142 as the top brush passes over the corresponding segments of distributor ring 156, while relays 142 and 144 remain de-energized. Relays HI and 142 lock over their own make contacts and break contact of relay 1 and close circuits for relays H9 and 120, the former over make contacts of relays 142 and 14 i, the latter over make contact of relay 14 l Relays 1 I 9 and 120 prepare circuits for the glow lamp indicators low tens units fractions and last tens units fractions shown on Fig, 8, thereby insuring that the subsequent price transmission will be registered upon these glow lamp indicators. The other ranges select the other indicators in a similar manner by means of relays 1I5 to 120, depending upon which of the four range register relays Hi to 144 are energized during the range transmission.

Following the range transmission, the top brush passes over the next four segments of distributor ring 156 during which time the tens digit of the price is transmitted and registered upon the four relays 13I to 134 in the above described manner. Assuming that the tens digit of the price is 2, represented by marking current during the second impulse space, only relay 132 will be energized during the transmission. After the transmission of the tens digit of the price is completed, a circuit is closed by distributor ring 159 for relay 166, whereby the selection registered on relays 13l to 134 is transferred to one of the ten control relays 10! to 1 I 0. In the instance under consideration, relay 102 is operated over make contact of relay 166, break contact of relay "I, make contact of relay 132 and break contacts of relays 133 and 134. The make-before-break contact of relay 102 corresponds to key 2 in Fig, 4.

At the same time relay 11 l, which is in series with all the relays 10i to 1), has operated, closing at its make contact circuits for short-circuiting the tens glow lamp indicators previously selected by the operation of the stock selection and range relays. In the present example, this circuit is traced from the anodes of lamps low tens and last tens in Fig. 8, over make contacts of relay 850, to Fig. '1 and there over make contacts of the operated range relays 119 and 120, break contact of relay 1, make contact of relay 166, break contact of relay 112, make contact of relay 1| I and break contacts of relays 10l, 103 and H0 to cathodes l, 3 to 9 and 0 of the above-mentioned glow lamps. Relay 102 being operated, the short circuit for cathodes 2 is traced from make contact of relay 1 over rectifier 160 and make contact of relay 102 to cathodes 2.

Relay 1 in turn closes a circuit for relay 112, whose contacts correspond to key 424 in Fig. 4. Relay-112, being of the ordinary telephone type, requires several milli-seconds for operating. During the interval after relay 1 operates and before relay 112 operates, the oathodes which may be glowing in lamps low" tens and last" tens are extinguished over the abovedescribed short-circuit. The interval is more than long enough to accomplish this, inasmuch as the lighting as well as the extinguishing of glow lamps takes place in a fraction of a mini-second. When relay 112 operates, the short-circuit is opened at the break contact of this relay, battery 1" connected between the main battery and the anodes of lamps low" tens and last" tens and battery 160 placed in parallel with rectifier 100. As explained above, this results in starting the discharge on those cathodes where the two additional pote tials come together, that is, cathodes 2 of lamps low" tens and last tens.

Two segments later, distributor ring 159 opens the circuit of relay 166, which in turn releases relays 102, 1| I and 112. At the same time the holding circuit for relays 12l to104 is opened by distributor ring 160, causing the release of relay 122. When relay 166 releases, the additional potential from battery 1" is-removed from lamps low tens and last tens, but the discharge is maintained as described above in connection with Fig. 4.

Meanwhile the units digit of the price has been registered on relays 1 to 124. After the transmission of this digit is completed, distributor ring 160 closes a circuit for relay 161. If the units digit be 8, corresponding to marking current during the fourth impulse space, relay 124 will be energized at this time. As a result, the operation of relay 161 closes a circuit for relay 100 over make contact of relay 161, break contacts of relays 12l, 122 and 123, and make contact of relay 124. Relay 1 operates in series with relay 106 and closes the short-circuit for lamps low" units and las units over make contacts of relays 850, N9, and 161, break contact of relay 112, make contact of relay 1| I, break contacts of relays 10l to 101 and 100 to 1" to cathodes I to 1 and 9 and 0, as well as over make contact of relay 108 and rectifier 168 to cathodes 8. Subsequently relay 112 operates and causes the starting of the discharge on cathodes 0 of lamps low units and last" units. Two segments later, the circuit of relay 161 is opened by distributor ring 159, causing this relay and relays 108, 1 and 112 to release in succession. At the same time the holding circuit of relay 124 is opened by distributor ring 161, causing the release of this relay. In this manner the selected units digit 8 is registered on the lamps low units and last units.

Meanwhile the fractions digit of the price has been registered on the four relays 10l to 134. Assuming the fractions digit to be '7, represented by marking current during the first three impulse spaces, relays 12!, 122, and 103 are energized during the fractions selection. After the fractions selection is completely transmitted, the brushes of the distributor pass from, the last segment back to the first and thereupon the clutch is mechanically disengaged, thus stopping the rotation of the brushes. If the sender is ready for the transmission of the next quotation, the clutch will be immediately energized again and the fractions digit will be registered upon the lamps low" fractions 7 and last fractions while the hundreds digit of the next stock selection is transmitted over the line. If the sender pauses before transmitting the next quotation, the-brushes remain on the first segment until the next quotation is transmitted. In either case the fractions digit is registered on the lamps as follows:

When the brushes return to the first segment, a circuit over ring I59 is closed for relay I I4 which operates, in turn closing a circuit for relay I86 over make contacts of relays H3 and Ill, distributor ring I58 and its associated brush. Slow releasing relay H3 is normally energized over a break contact of relay Ill. Relay I66 closes circuits from the contacts of relays IN to I24 to the ten relays Ifll to H0. In the present example, relay I01 is operated over make contacts of relays I66, I3l, I22 and I33 and break contact of relay I34. Relay III operates in series with relay IOI, causing the above-described operations, including the extinguishing of lamps low fractions and last" fractions, the operation of relay "2 and the starting of the discharge on cathodes 'I of lamps low fractions and last fractions over make contacts of relays 850, N9, I20, Ill, I66, "2, batteries Ill and "0, make contacts of relays H2, battery I69, make contact of relay 101 to cathodes i.

When relay H4 operates, theholding circuit of relays I62 and I65 is opened, causing the release of these relays or of whichever hundreds and tens stock selection relays may be energized at this time.

At the same time the circuit of slow-releasing relay H3 is opened, but this relay remains operated for a certain perioddue to its slow-releasing feature.

The holding circuit of relays Ill to I44 and of the stock selection relay, such as 850, is transferred by relay H4 from direct ground to ground over the make contact of slow-releasing relay H3, distributor ring I58 and its associated brush. The holding circuit of relays IN to I34 is maintained over a make contact of relay H3. These relays therefore remain operated for the time being.

If the next quotation is immediately following, relay II 3 has not sufilcient time to release. As the brushes pass from the second segment, the holding circuit for relays IN to I34, Ill to I, Iii, and stock selection relay 850 is opened by distributor ring I58, causing all these relays to release. A segment and a half later, the circuit of relay Ill is opened by distributor ring I59, causing this relay to release as well, thereby restoring the fractions control circuit to normal and closing the circuit for relay H3.

If the sender pauses before transmitting the next quotation, the brushes remain on the first segment and relay I I4 stays operated long enough to cause the release of slow-releasing relay II 3. The release of the latter opens the holding circuits of relays I3l to I34, IM to I44, I66 and stock selection relay 850 at make contacts of relay H3. All these relays release, restoring the entire circuit to normal, with the exception of relay 1 which stays operated until the next quotation is-transmitted.

If it is desired to extinguish a lamp without lighting a new numeral, code 11 is transmitted, causing the operation of relay II I direct without operating one of the relays IM to H0. As a result, the short-circuit for the lamps is closed but no circuit set up to light another numeral. The circuit for relay II I is traced over make contact of relay I06, I3I, I32, break contact of relay I88 and make contact of relay IN or over make contacts of relays "I, IN, I22, break contact of relay I23 and break contact of relay I24.

From the foregoing it will be evident how the other ranges operate and it will not be necessary to go into a detailed description of these operations. Moreover, it will be clear that any desired number of receivers may be operated simultaneously from the same sender over the same line. Other possible applications of this invention will be evident to those skilled in the art and the invention is not limited to the applications and means shown in the foregoing description or the associated drawings except as set forth in the appended claims.

I claim:

1. An annunciator system comprising a plurality of indicator units, each comprising a plurality of indicating gaseous discharge glow devices, said devices being characterized in that a materially higher voltage is required to start a discharge therein, than is required to sustain a discharge therein, means normally applying a sustaining voltage across each of said devices, selecting means effective for selecting desired ones of said units, means for then momentarily removing the sustaining voltage from the devices of the selected unit and again re-establishing the same, said selecting means serving after the re-establishment of said sustaining voltage to subject predetermined devices of the selected unit to a starting voltage to start discharges therein, said sustaining voltage thereafter being effective to maintain said discharges independently of the starting voltage.

2. An annunciator system comprising a plurality of indicator units, each comprising a plurality of indicating gaseous discharge glow devices, said devices being characterized in that a materially higher voltage is required to start a discharge therein, than is required to sustain a discharge therein, means normally applying a sustaining voltage across each of said devices, selecting means for selecting said units in predetermined order, means including said selecting means for momentarily removing the sustaining voltage from the devices of the selected unit and again re-establishing the same, said selecting means serving after the re-establishment of said sustaining voltage to subject predetermined devices of the selected unit to a starting voltage to start discharges therein, said sustaining voltage there-v after being effective to maintain said discharges independently of the starting voltage.

3. A plurality of gaseous discharge glow devices arranged in groups, said devices being characterized in that a predetermined voltage is required to start a discharge therein, means for selectively subjecting all the devices of a desired group to a portion of a starting voltage, and means for selectively subjecting a desired device of each group to a complementary portion of said starting voltage, to start a discharge in the selected device of the selected group.

4. A plurality of gaseous discharge glow devices arranged in groups, said devices being characterized in that a materially higher voltage is required to start a discharge therein, than is required to sustain a discharge therein, means normally applying a sustaining voltage across each of said devices, means for selectively subjecting all the devices of a desired group to a portion of a starting voltage, means for selectively subjecting a desired device of each group to a complementary portion of said starting voltage, to start a discharge in the desired device of the desired group, the discharge being maintained in said desired device independently oi the starting voltage by the sustaining voltage.

5. A plurality of gaseous discharge glow devices arranged in groups, each of said devices including an anode and a cathode and being characterized in that a predetermined voltage is required to start a discharge therein, a plurality of common anode connections each connecting the anodes of all devices in one group together, a plurality of common cathode connections each connecting corresponding cathodes of all the groups together, means including said anode circuit connections for selectively subjecting all the devices in a desired group to a portion of a starting voltage, and means including said cathode circuit connections for selectively subjecting a desired device in each group to a complementary portion of said starting voltage to start a discharge in the desired device of the desired group to the exclusion of all other devices.

6. A plurality of gaseous discharge glow devices arranged in groups, each of said devices including an anode and a cathode and being characterized in that a materially higher voltage is required to start a discharge therein, than is required to sustain a discharge therein, anode circuit connections individual for each group, individual circuit connections for each cathode, said cathode circuit connections being multiplied to corresponding cathodes of other groups, means for normally applying a sustaining voltage across each of said devices, means including said anode circuit connections for selectively subjecting all the devices in a desired group to a portion of a starting voltage, means including said cathode circuit connections for selectively subjecting a desired device of each group to a complementary portion of said starting voltage to start a discharge in the desired device of the desired group, said sustaining voltage thereafter being eifective to maintain said discharge independently of the starting voltage.

7. A plurality of gaseous discharge glow devices arranged in groups, said devices each including an anode, a cathode and a control grid and being characterized in that the decrease of a negative bias voltage applied to the control grid results in a decrease of the voltage required to start a discharge in the device, means normally applying a predetermined negative bias voltage to the control grids of all the devices, means for selectively applying a voltage across the anodes and cathodes of all the devices in a desired group, said last mentioned voltage being insuiiicient to start a discharge in the devices with said predetermined bias voltage applied to the control grids, and means for selectively decreasing said bias voltage applied to the grids of a desired device of each group to start a discharge in the desired device of the desired group.

8. A plurality of gaseous discharge glow devices arranged in groups/said devices each including an anode, a cathode and a control grid and being characterized in that a materially higher voltage applied across the anodes and cathodes and a materially lower bias voltage applied to the control grid is required to start a discharge therein, than is required to sustain a discharge therein,

means normally applying a sustaining voltage across the anodes and cathodes of all devices. means normally applying a bias voltage to the control grids of all devices, means for selectively applying an increased voltage across the anodes and cathodes of all the devices in a desired group, and means for selectively decreasing the bias voltage applied to the control grids of a desired device of each group to start a discharge in the desired device of the desired group, said sustaining voltage thereafter being eflective to maintain said discharge independently of said increased voltage across the anodes and cathodes and of said decreased bias voltage,

9. A plurality of gaseous discharge glow devices arranged in groups, said devices each including an anode, a cathode and a control grid and being characterized in that the decrease of a negative bias voltage applied to the control grid results in a decrease of the voltage required to start a discharge in the device, a common cathode circuit connection for the cathodes of all the devices, a plurality of common anode connections each connecting the anodes of all the devices in one group together, a plurality of common grid connections each connecting corresponding grids of all the devices together, means normally applying a predetermined negative bias voltage to the control grids of all the devices, means for selectively applying a voltage across the anodes and cathodes of all the devices in a desired group, said last mentioned voltage being insuificient to start a discharge in the devices with said predetermined bias voltage applied to the control grids, and means for' selectively decreasing said bias voltage applied to the grids of a desired device of each group to start a discharge in the desired device or the desired group.

10. A plurality of gaseous discharge glow devices arranged in groups, said devices each including an anode, a cathode and a control grid and being characterized in that a materially higher voltage applied across the anodes and cathodes and a materially lower bias voltage applied to the control grid is required to starta discharge therein, than is required to sustain a discharge therein, a common cathode circuit connection for the cathodes or all the devices, a plurality of common anode connections each connecting the anodes of all the devices in one group together, a plurality of common grid connections each connecting corresponding grids of all the devices together, means normally applying a sustaining voltage across the anodes and cathodes of all devices, means normally applying a bias voltage to the control grids of all devices, means for selectively applying an increased voltage across the anodes and cathodes of all the devices in a desired group, and means for selectively decreasing the bias voltage applied to the control grids of a desired device of each group to start a discharge in the desired device of the desired group, said sustaining voltage thereafter being eilective to maintain said discharge independently of said increased voltage across the anodes and cathodes and of said decreased bias voltage.

HANS P. BOBWAU.

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