US2612551A - Paging system - Google Patents

Description

2 SHEETS-SHEET 1 Sept. 30, 1952 J. E. KREINER PAGING SYSTEM Original Filed Feb. 26, 1949 INVENTOR. JOHN E. KREINER B fi/ww ATTORNEYS "m z. 5 4 38 K o FIG.3

2% Fsd'iws ARC J. E. KREINER FACING SYSTEM Sept. 30, 1952 2 SHEETS-SHEET 2 Original Filed Feb. 26, 1949 INVENTOR. uorm KREINER 5 VI F- N R o A Patented Sept. 30, 1952 Paerriu SYSTEM John E. Kreiner, Palatine, Ill., assignor to Edwards Company, Inc., Norwalk, Conm, a corpo;

ration of Newv York Continuation of application Serial No. 78,657, February 26, 1949. This application April 7,

1951, Serial No. 2l9, 834' I This invention relates to signalling systems for initiating signals locally and selectively for controls at one or more remote points; this application is a continuation of my application Serial No. 78,657, filed February 26, 1949,now abandoned."

9 Claims. (Cl. 177353) The present invention relates to signalling systerns employing both visual and audible signals. More particularly, it relates to that kind of a system in which a coded visual and audible signal is reproduced at a number of stations distantly located from the operator of the system as well as upon a monitor locatedto be readilygand con veniently observed by the operator. Such systems are of use in paging personnel in hospitals, industrial offices, or other commercial'buildings,

and manufacturing plants. A system of this'type is of particular use as a doctors paging system in a hospital, and in the preferred embodiment of the invention hereinbelow described, for convenience and simplicity, it will be described in terms of such use. However, it is to be understood that the invention'is not limited to such specific use, but may be applied to any of the other uses for which it is suitable.

Prior art code signalling and paging systems one hundred and twenty different codesymbols; such as I23, I24, I34, I45, etc., may be obtained by using no more than three digits at a time. For most'practical purposes. this is suificient, but it is obvious that this number, one hundred and twenty, may be greatly increased'by using also.

code symbols of one digit, two digits, or morethan three digits. Although there is no additional mechanical or electrical difl'iculty in arranging a system of the type herein contemplatedto-use code symbols of fewer or greater than three digit combinations, experience in practical operation and use of such systems has shown that one limited to producing three digit combinations causes a minimum of confusion and error among those using the system.

It is highly desirable that code symbolssfor more than one person can be set up on the system and can be shown at the signal stations at prac In practice'it is desire If the digits 1, 2, 3, 4, 5, 6, '7, 8, 9, and 0 frequent replacement'or maintenance. The c'om- 2 tically the same time, that is, one following'the other inrapid succession. Here again experience has taught that in most installations it is sufficient if the code symbols for three persons can be set up on the system simultaneously. In some installations it maybe desirable to have a system on which more than three code symbols can be set up simultaneously, but such instances are the exception. Accordingly, in the following discussion of the priorart and its deficiencies andin the description of an embodiment of the present invention, a system using combinations of three digits for its code symbols and capable ofv producing three code symbols simultaneously will be considered, but it 151110 be understood that when so desired the present invention is readily applicable to a system employing other combinations of digits for code symbols and producing more or less than three code symbols simultaneously. 1

In order to accomplish these two desired results, that is, a'relatively large number of code symbols and the presentation of more than one code symbol at a time, there has been required in the prior art systems 'veryexpensive and complicated selecting and operating devices. These have included commutator devices having at least one pole for each individual signal circuit and which are driven continuously during the operation of the system and'cause contact of every pole each revolution, relay-operated contacts for each light flashed, and at least one timing relay for each set of code symbols set up on the system. Such complicated devices have numerous disadvan-. tages.

The use of a continuouslydriven commutator causes wear on all moving parts whether the corresponding code symbols are being exhibited or not, thus causing excessive noise and 1 structed inaccordance with the present invention,

which eliminates the use of a commutator witha large number of poles and reduces the number of relays in the control circuits of the system to onesingle contact relay located for each digit employed in forming the code symbol combinations.

' for selective signal transmission.

It is thus an object of the present, invention to provide a system in which one or more coded visual and audible signals can be set up and flashed intermittently and in sequence at distant signal stations and in which no part is being driven when the system is not in operation, and in which the number of contacts at which electric current is made and broken during operation of the system is reduced to a minimum.

It is a further object of this invention to pro vide such a system in which the number of partsv subject to'wear and to the effect of sparking is reduced to a minimum. 7

It is a further object of this invention to provide such a system in which all the control elements and connections are arranged to be con-- tained in a housing which is adapted to serve also as an operating switchboard and monitor.

It is a further object of this invention to provide such a system which is positive and dependable in operation and can be manufactured economically. a ,Another objectis to-provide a signalling system ,of the above-mentioned general type in which efficient use is made, for signal transmission, of each. successive portion of a complete cycle throughout the operationpf the system. particularly where the number .of code symbols wee transmitted during anyone cycle is less than the full capacity of the particular cycle of the system; another object is to carry outthis object ina practical, inexpensive, and dependable manner. I

Another object is to provide a signalling sys-,

tem of the just-mentioned type in which each of the successive portionsv of a complete cycle is automatically caused to function for signal trans,

mission even though the fuILcapacit'y per, cycle to transmit different code-symbols is not utilized.

Another object is to achieve, in a dependable, inexpensive, and .efiicientmanner, the automatic allocation for signal transmis'sionof such of the successive portions of a-complete signalling cycle as are idle'or unallocated so long as one or more of them is otherwise'functioning and allocated The invention accordingly consists tures of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims. a 7

Various other objects, advantages, and features of the invention will become apparent from the following detailed description taken in conjunction with the appended drawings, in which Fig. l is a perspective view of the control box showing the arrangement of the control keyboard andindicating monitor which shows, in a 'diav grammatic way, one

tions; Y

,Fig. 2 is a schematic drawing of the electric of the outlying signal stadevices and their associated circuits employed in the operation and control of the system; and

Fig. 3 is a schematic circuit diagramshowing the mannerin which the lamps and buzzers at the outlying signal stations are operated by the relays in the control circuits.

Referring to Fig.'l,'C is the control box which is located conveniently near the operator of the system and which contains all of the control api ofthe system are readily accessible for inspection,

adjustment, or repair. All of the operating keys and the indicating monitor are mounted on top -face lil The indicating monitor i3 may be formed by inserting in top face it) a piece of opaque materiaLsuch as coated glass, with the characters 1, 2, 3, 4, 5, 6, '7, 8, 9, and 0 etched thereon in such a manner that these characters form translucent portions through which small incandescent bulbs can throw their light when they are illuminated. It is to be understood that these characters may be formed in any other suitable way, as. byhavinga strip of material into which they have been cut'underlying a pane of glass or translucent plastic material. Below in- Y dicating monitor 13 there are arranged three rowsof selector keys or push buttons K1 to K10,

K11 to -K20, and K211 to K30, respectively. The

selector keys 'ineach row bear numbers 1 to 9 and 0. Ateach end of each row of selector keys arev placed additional keys or push buttons, one group of' three: $1,511, and S21 at the right, as viewed in Fig-J1, are starting keys, and one group of three SS1,SS11, and S'Sz v at the left, as viewed in Fig- Lare stopping keys, Starting and stopping keys si, S 1, S21, SS1, SSn, andSSzl each control multiple; contact switches, the operation of which-willbe described in. more detail herein below.- The selector keys are arranged so that thenumbers thereon are directly in line with the corresponding numberson indicating monitor 13, and starting keys S1, S11, andSz are placed directlybelow the word Start and SS1, SSH, and

' SSL'I) directly below the word Stop etched or in the feaparatus and control circuits of the system, the

C may be of any suitable shape "and size to prootherwise shown on indicating monitor l3 at the ends of the row of digits shownthereon. A switch, preferably-a toggle switch, A is mounted in an escutcheon it which ismarked on and off to show the respective position of switch A and.

islocated below the above-described rows of keys orin any other suitable location. Switch A controls the operation of audible, signalling devices such as buzzers. r

The detailed mode of operation of the system will. be explained at greater length hereinbelow, but at this point it'appears desirable toexplain briefly the mode of operation from the operators standpoint;

If it'is desired to call a doctor whose code symbol, say, is 146, the operator depresses selector keysKi', K4, and K6 and then depresses starting key Sr onthe same. row as selector keys K1, K4, and K6. The selector keys and starting keys operate switches of conventional design which are of the lock type, that is to say, remain in their depressed positions until released. This action causes the proper lamps L'1, L'4, L's, L"1, L"4,

L"s, etc., to light and flash 146 at the variousoutlying signal station s/such as D, and also to appear on indicating monitor 13. This flashing both at the outlying stations and on the indicating monitor will continue until the operator depresses stopping key SS1, which releases the switches actuated by selector'keys K1, K4, Keand starting key S1, thus stopping the flashing of the signal. I

If at any time during the flashing of a signal D as desired.

the operator desires to produce an audible signal in addition to the visual signal, hemay: doso: by pullingswitch A to its on'position. This will cause an intermittent audible signal. to be pro- 'duced at each outlying "signal 'station D, while switch A remains in that position;

".Should the operator desire to. call a second doc.-

torat the same time that the doctor whose code symbol is 146 isbeing called, the procedure described above for'calling thedoctor whose code symbol is 146 having been followed, the operator depresses selector keys in the second row'representing the second doctors'cod'elsymbol, say .257'-that: is, K12, K15, and- K1v-and depresses starting key S11. Both code symbols "146 and "257 will flash at the outlying signal stationsD and on indicating monitor 13 in a sequence hereinbelow described.

Likewise, the call for a third doctor-whose code symbol'is, say, 670, may be added'by' the operator depressing selector keys Kzs, K27, and 1&0 and starting key S21. This will result in all three code symbols 146-, 257, and 67-0 being flashed intermittently and in sequence at the outlying signal stations D andon indicating monitor i3.

When it is desired to stop flashing the code symbol of any one doctor when more than one is being paged, without interrupting the paging of the others, this. may be done-"merely by depressing the proper. stopping key- SS1, $811, or S521, For example, should the doctorwhosecode symbol is 257 answerthe call of the operator, theziiashing. of thatcodesymbolmay be stopped by'the operator depressing stopping key 3811.

1Likewise,.it is to be: understood that the; creation ofJan audiblefsignal is entirely dependent on. the positionof switch A andthat such. signalcanbe started or stopped at any time during-theilashing of one or more code symbols: byoperating. switch A..

The foregoing has explained the general mode of; operation-from, the standpoint-of one operating the systemand of the end results. It now remains to explain how this is accomplished in a direct, simple, foolproof, and efficient manner by (they use, of simple devices associated in novel circuits to accomplish this end.

The signals may be. arranged at. the outlying signal stations D in: anymanner desired so-long as: a visual indication of a number of combinations of one ormore digits or similarcharacters is possible.

The. usual arrangement is to have a column of incandescent lampsarranged. in separate: compartments in a housing with a. numbored translucent window for eachlamp. These lampsmay be supplied with current-fromJthe usual house lighting or power supply'circuit. of th e'usual voltage of 115 or 230 volts,,a-nd which. is

usuallyA. C.,and are connnected to. suchcircuit in any convenient manner either; permanently or by a wall plug l5. and cable I 6 as shown: in, Fig. 1. Their respective circuitsarepreferably relay-controlled. It is to be understoodthat there maybe as many outlying signal stations;

Referring toFig. 3', manner in-which' lamps 11 1, L'z, etc., L-1,-L"2, etc., and L"1, L!"z, etc.,

are connected to. the power supply, is'sh'own; These lamps areconnected across the. terminals of. such a supply; with a, relay-operatedswitch,

of the same digit are preferably parallel. to each other. Thus, when one of. these relay-operated.

switches'such'as RC1, is closed, as-will be more specifically 'described'hereinbelow, the lights at all the outlying'signal stations corresponding to that particular digit will be lighted. "Likewise, the "audible signal devices such asybuzzers, as shown at B,B"', and B', at'the outlying signal stations'are connected across the same supply as lamps L'1-, L 'r, L""1, etc., 'and'controlled by a relay-operated switch'ARC; I

In Fig. 2' there is shown'in a schematic'inanner the wiring of the control circuits contained in control box C. For a clear understanding ofthe invention, it should be noted at the outset' that the series of relays R1-to R10, inclusive, close contacts RC1 to RG10, inclusive, shown in Fig. 3, and relay AR closes contact-ARC, also shown inFig. 3, whencurrent'isrunning through the respective relay windings. Therefore, when current is flowing through any one or more of relays R1 to'Rm, inclusive, or relay AR, respective lamps L'1, etc.) arelighted at the outlying signal stations-and an. audible. signal. is produced at those stations by buzzers B, B", and 13". "With thisunderstanding in mind, it is unnecessary to describe further the functioning of the lamps at the outlyingsignal stationsD, and the description maybe simplified: by writing-it inthe terms of the functioning of the pilot lamps P1 'to- P10, inclusive, in the. indicating monitor ['3. which are inparallel with the respective coils of the relays. R1 to Rm, inclusive. Generally in installations -therelays RiRCi to R10 RG10, AR ARC and the supply transformer T (where the system is to beoperated by alternating current) are not actually contained incontrol box C, since no particular purpose would be accomplished thereby and to-so include them would unnecessarily increase the size of the control box.

The primary ofastep-down transformer T is connected. across the input terminals [8. As abovestated, transformer T isv conveniently located: remotely from the control box C, and-in the usual. installation the circuits included in control box C start with the terminals of secondary [9 of transformer T The control circuits are connected acrossthis-secondary I 9. Although transformer .T'may be d'esignedto-gi ve any desiredlow 'voltagefor operation of the control circuits, it has been found in practice" that a potential of 24 volts i-s adequate for proper operation of the control circuits and is sufiiciently low=to prevent any detrimentaleffect in the few make-and-break points in the eontrol'circuits.

Further, when onlya direct current source of supply is available, transformer T may 'be replaced by' 'a suitable potentiometen; or, of

. proper-voltage, such supply-maybe directly con- I suchas RC1, in the circuit-of each groupof lamps. 1 L! 1, L"1', Lf1,-etc., of the same digit. All lamps nected. The only other change required .in. the system-for direct circuit: operation would be the replacement of the synchronous or other suitable type of -A. C. motor'hereinbelow described by a suitable direct current device.

, The control circuit for the audible 'signalsis connected-across" secondary; l'fl'of transformer T and comprises, in series, switch M the opening and closing of which is determined by a synchronous motor drivenyimpulsing unit .I; in a manner to be described h'ereinbelow; switch A, the position and physical formv of which are. hown inFig. l; and the winding of audible signal' relay whose'armature or contact .ARC (.see Fig. 3) functions to 'close the audible signal circuits'in the -volt line across'whicli the buzzers-Bf', B", B, etc., of thel,outlyingsignal: stations D are connected. It is thus seen that allocated to them,

- the-winding of audible signal relay AR. is' 'en'ergized andthe circuit operating buzzer's B"; B1; 13, etc., is closed only when 'bothswitches; MA and A;are closed; 1'

There are three sets or banksofvisualfsignal control circuits, one set'for each rowor bank of selector'keys K1, K11, K21. Each of these setsor banks-of-circuits includes pilot'lights P1, -P2,-P3, etc., and the respective windings of..visual signal relays R1, R2, R3, etc., which are conveniently in shunt'with theirrespectivepilot lights and the contacts RC1,-RC2, RC3, etc., ofwhich (see Fig. 3), operate the circuits to light the signal. lamps at the outlying stations D. There is also included in-each of these sets of control circuits a switch M1, M11, or M21 operated by impulsing unit :I which, as' above stated, also operates switch MA, a-switchE1,'E11, or'E21 operated by starting keys $1,3 1, or 821, and stopping keys SS1, S311, or S821, respectively, in a manner to be described herein.- after, and a series of selector switches k1,. k2,"etc., I011, 7012, etc., or R21, k22, etc., operated bya correspondingly numberedselector key. (see Fig. l). Itisto be understood that there is onelimpulsing switch, such as M1, andone' switch, such as E1, for'eachgroup or bank of control circuits; and one selector switch, such as k1, for each circuit in each group of circuits. Thus, referring to'Fig. 2, thethree banks'or groups of selective circuits having respectively the selector switches k1, k2, etc.,-k11, lc12,getc., and R21, kzz, etc., have normally respectively, the pulsing switches M1, M11, and M21 which, as later-"explained, are successively actuated during each cycle, each for a certain fraction of the cycle, and the groups of selectivecircuits may be subjected'to the control of their respectively allocated impulsing switches M1,-M11, and M21 by the switches E1, E11, and E21, respectively. However, as later explained, I provide means for automatically re-allocating the impulse switch (M1, M11,

or M21) in response to idle or deenergized condi-. tion of its group of selector switches, to the additional pulsing of the circuit of an active'or energized group of' selector switches. .Injeach circuit, between the selector switch, such as k1, and the correspondingpilot lamp P1 and relay R1, there isinterposed a one-way-curr'ent device V1, suchas a metal oxide half-wave rectifier,

which allows passage of current in the one direc-i tion, that is, selector switch to pilot lamp, but prevents the passage 'of current in the opposite direction, thuspreventingtheestablishment of current paths-for undesired currents in that direction. V

A .motor, preferably a constant-speed motor, shown in Fig. 2, at SM, is used to drive impulsing unit I. Itis preferably asynchronous motor of any suitable form andneed not be described in detail here since the design and characteristics of suchfmotors are well known to those skilled in theart. Sufiibe it to say that a synchronous motor is chosen to have the proper number of revolutions per minuteifo'r the voltageand frequency-used to causeirnpulsing unit I associated therewith to open and close switches MA, M1, M11, and M21 the desired number of timesper minute. Synchronous motor SMis connected across sec- 1 1111221171 of transformer T, but switches F1, F11, and F areinterposed in that circuit so that synchronous motor SM will run only when one or more of these switches is closed. Switches F1, F11, and F21 are mechanically connected to starting keys S1, S11, and S21 and stopping keys SS1, SS 1;;and SS21, respectively. I

the present embodiment, where three code symbols can be setup on the keyboard at once,

switches M1,.3M11, and M21 preferably arej ar-= ranged so thatone of them is closed for each portion of a cycle of operation of the system'andv are closed in the order stated. If the system- In the present-embodiment, switchi MA closes once for eachjcycle of operation of the system but,'if desired, switch M11 may readily. be"*'designed to close each time one of" the switches M1, M11, or M21 closes, that is, threetimes. each cycle. However, itis not generally considered. desirable inj systems of this type to have the audible signal repeated every time a visual signal is flashed;. therefore switch MA, in most installations, is arranged to" close only oncev for each cycle of operation although three visual signals are flashed during that time.

All of the starting and stopping switches E1; E11, and E21 and F1, F2, and F3 are preferably and conveniently of; similar construction. 1 Depression of starting key S1 closes motor-circuit switch F1 and closes group-selector switch E1: at contact hr of the latter, thus puttingthe corresponding group ofselective circuits (the. upper groupgin Fig. 2) in active condition where it can'loe'energized under the control of the impulsin unit; the normally at-rest position of these switches F1 and E1, which can be single-pole'switches', is open, being closed upon depression of thestarting key S1 and opened upon. depression of the stoppin key SS1, (Fig. 1).

or bank in Fig. 1,. and thus closing corresponding switches (K11, 71:12, etc.) in thesecondbankf-of Fig. 2, closes normallyopen startin switches F11 depression'of starting key S21, in the third bank or row of Fig. 1, effects open starting switches F21 and E11. JSimilarly,

-Provision is made, however, incase' all of the" groups of selective circuits'are not placed in ac tivatedconditiom to re-allocate, in response to idle'or de-activated condition of the inactive:

grouper groups, the pulsin switch or switches normally allocated to them and to repeat the signalling efiected through an ac} tive group or bank of selective circuits. H

provision of a back contact for each of the switches E1, E11, and E21, shown in Fig. 2 at 01,

c11,-and 021, respectively, with circuit connections respectively leading therefrom to the pulsing switches other-"than those normally allocated to the respective groups of 'selectivecircuits, these back contacts and circuit connections becoming their respective groups of circuits are (lo-activated, as by opening of switch efiective according as Thus a conductor 27 leads from back contact I In similar manner; depression of starting key S11, after the desired. selector keys are depressed, in thesecondrow' and M21 normally respecduring the cycles ,make such pulsing switch orsWitcheseITectiVe' A con-' venient means for this purpose comprises the 1:21 of starting switch E21 of the t ;hird"grou1: of circuits-" to "the cohta-ctof pulsing switch M1 which is normally allocated {to the first group of circuits; a conductor 26 leads from the back contact 011 of the "secondjgroup- 'selector or starting switch E11 to the'contact'of pulsing switch M21 which is normally allocatedito the third group; and, as shown; a conductor leads from the back contact- 01' of the first-group selec tor-or starting switch to. the switch coint'adtjof pulsing switch M11 which normally serves the second group of selective circuits; How this' farrangement responds to different" conditions is later 1 described in detail. While the sequence iof direct electrical connectionsfromtlie group 'sej lector switches E1, E11, and E2; to the -contacts" of the sequence switching devices M1',, M11,f and Mn is in the order just named; the-electrical coirnections from the back=contacts c1, cu, czi are in thesequence 01, to M11, cu toM 21; and "cziito M1,--being in efi'ect a" phase displacement'of-one tirne'interval (illustratively; 120i) of thecycle, As above stated, starting keysSi', etc."(seie Fig.

1); andselector" keys K1, etc, when depressed; remain in that position untilreleased. Thisre*-.

lease" is accomplished by depressing the respective stopping key" SS1. Whe'n'stoppin ke'y'fS'S' is depressed; starting key Stand" whichever of selector keys K1, etc;, hacl'been depressed" released, and the corresponding 'selctor "switch kflletc are opened and 'switchEi returns to its normalposition, breaking theorem-tremor bi andclosing the circuit from Jdi to cf; Like fi s e; switch'Fi is'openedand synchronous motor SM stops, unless energized throughpnei'o'f the other switches'F1'1 or' F21 that may be in af closed post? tiOIL' j f Toexplain the operation of the systematic thefun'ctioning of the various elementsfin the control circuits, the same series of examples win be used that were"described'nereina bove when the operation from the operatorsviewpoint was discussed. When the operator desiring to 'nfd out the'codesymbol 146" depresjse selector" eys K1, K4, and K6; corresponding switches 101; k; ks are closed. The next operation starting key' S1, closes correspcndmgsw E1 and Fl These manual" operations". thf erator performsin the uppermost ortcpr: of keys'as seen in Fig". 1', and inflthi'sjassutnedjillus tration, since no other code symbolsiareto-he set up and transmitted; the operator' leaves the jsecf-i end and thirdrows or banks of keys (in both Figs; 1' and 2')" alone, thougn tneyare usable'tc setup two more-code symbols, as will h'llalter pointed out. In the circuit diagram of Fig. '2, with switch E1 closed, the circuits" of t bank are placed directly under the "'c pulsing switch M1 which tested to tenor mally allocated to that u perbank; In pulsing unit I closesswit'ch Mi, current w'ilipass' through pilot lamps P1, P4; and Pt" and relay:- W ind in'gS' R1; R4 andRs; This'circilit maybe leads 20 and 23, switch M1, contact at t" roi switch E1 and then in three b'rn-c es-ewitcuikt, rectifier V1, pilot la'm'p' P1,? and" rent "windin f Ri; switch 704, rectifier V4, pilot lamp P r WindingRt; and switthktiwtifier V ,,piloft mp P6; and relay" winding Rs' trrretum 1eads'2'tt and 22 back'to secondary-1:19. With rela s R1, R4, afidf'fl Rt energized, the corresponding (1' outth'ecodd symbol 146 are h'd at ,the' remote station orstatio'ns Drier, atfportiorf'o'f the cycle of the System" duringfwhicli' switdfiii remains closed.

"will ;open "and. witch will "close:

' 's witch' Mr'is 'thus opened'antl'would rein notes "fortherestof thecycleacondition whichotherv 't's'idle orunajllocat' d p e-comment and Edith, 5 of'the iitherjbank "0 c ci the 'seccnd bankf anestannigsmmn E21; of the third bangare open' at-"tneir "front contacts bit and 1m '(niakingfth'e corresponding banks of oilu t are closed at their With swit h'mt closed "thefjnext succeedi 1'1 Established I circuits, which l46"' was being sent, si

quringtwntch switch. Mai-remains closeTd; Under these conditions a circuit will again b estab "thatwhe'h omy'tne cone ;;146;," fislsetlup, it is nasneafat' the outlyingsignal stations: D three times or every cycle 10f operation onimpmsing'unit "1; Though in the'just described illustrative operation t e under the central or 'puIs'in twitthMtdurin that'portion qr the-cyclealloc'atedto'switch Mi,- anw'wnue'the single code symbol is-set-upon only the one bank of keys'an d-selective circuitst thereni-aining pulsing switches normttny allocat'd to respective banks of keys and selective idle, become successively allodated 5' flied Cfibdfstvltbhiilghhii circuital rangement's' to re-activate: or again energize the sfi'g'n'als'a's initiall 's'e't up in the one bank, and

thus full use 'is madflof' theotherwise nd idle Letus ww proceed to explain the operation when a second tymboiflsay, 251911; added b i the operator depressing, in I the, s econdflgiroup bank; selector keysK z, til -at ain} andsta ting; key S1 on the switchboard. 'l jhisi operation, closes'sw'itches n2',;k1;, kn, E11 (so that contacts (iii-and D11 are bridged); angst-1; Switches 731 764; kt, .E1', and F1 remain, in the" position they; were;

in Before, "that is, only one code; symbol ce the I operator has not se ect est'arting'ke'y's and J cuits; m the illustrationystarting switch Ei't I portioniofbthe cycle; a. v

ough thesesame Tfi'symbol 146 will be flashed, and the circuits 1 l accomplishing this are thesameasthose which flashed 146 when only one code symbolwas be- "1 1g sent. When, however, 'switch'Mn i's'closed,

the flashing of code symbOl Fl l'GJ will not be ref.

7 peated because the circuit which .her'etoioreac-' complished this is open at contacts] (in, 01-1. of

-switch E1 the latter being in the secondbank or group, a group which now is not idle in that the second code symbol 257 is set up on it, andthe allocation of impulsing switch M11 .to other than the selected circuits of this second group, cannot therefore take place; Accordingly, when switch M11 is closed, .a circuit will be. establis'hed' from secondary [9 through leads 20, 23,.and125through switch M11 from'contact a1'1to b11 of switch E11; thence through three branches, switch'k z, rectifier V12, lead 1.02, pilot lamp P2, and relay winding-R2; switch Ins, rectifier V15, lead I05, ,pilot lamp Psgand relay Winding R; and switch 7e 7,

rectifier V12, lead I01, pilotlamp P7, and relay winding Rw toreturn leads 22 and.24 back tosec ondaryv [9, thus flashing the code symbol "5257.

at outlying signal stationsD and on monitor 'l3'. fWhen impulsing unit I closes switch, M21, a circuit willbe established as before through leads,

2l;23, 25,"a'nd 28 and'switchEzi from contacts onto :21, since this switch has remained. inlits up bykeysIKi to K1o; then that' set up. on'the second row, that is, set up by keys K11 t o Kzo; next the one on the first "again, then the'one'onthe firstZajgain', and then'the one on the second. in the terms of the example given, the sequence 146, 257, 4 :2 257, 6, 2 andsoon. 1". r

' This illustrates how, with an illustrative ca-. pacity of three code-symboltransmissions per systen i cycle,- the system utilizes those portions of each'cyclewhich would otherwise remain idle when less than the full capacity of code jsymbol selectiongis utilized, for the transmission or repetition ofan already selected codefsymboll When a third code'symbol, say, 670, is set upon the keyboard, this timeon the third or bottom row or group of keys'and circuits" in Figs. 1 and 2', all of the selector and, starting switches connected with the'first two rows of keys will'remain as above, but switches 7e26, km;

km, and E21 will be closed; that is, E2 -.'wi11 be inthe position that closes contacts (1 1, D21, and opens the circuit from an to 021. This, of course, is accomplished by the operator depressing keys Kai/K27, K 0, and S21. The third or bottom 12 M21 is closed, a circuit will be established. from secondary l9 through leads 2!], 23, 25, amaze, switch M21, and switch E21 from 1121 to ib21, thence by three branches, switch 1e26, rectifier V2s, 1ead I06, pilot lamp P6, and relay Winding Rs; switch I027, rectifier V27, lead I01, pilot lamp P and relay winding R7 and switch 1m, rectifier V30, lead H0, pilot lamp P10, and relay windingR o, throughreturn leads 24 and 22 back to secondary [9. In this situation the code symbols flashed at outlying stations D during the cycle will'be 146, "257, 670 in that order, and that sequence willfberepeated for each succeeding cycle until some change is made in the keyboard.

' ',.Let us now consider what will happen when it is deslredto stop the flashin of one-.of the .code symbols, say, 257, without disturbing the flashingof the other code symbols. Theo per ator depresses stopping key SS11, Which opelis switches kiz, 7e15, 1617,, E11 (that is, opens contacts an, birand closes contactsan, e11) andopens switch F11.

Motor SM continues to operate to 1 continue the cyclic repetition of its successive closures of switches M1, M11, M21, forfswitches F1 and F21, remain closed. Now, when impu'lsing .unitII closesfswitch M11, the code symbol 257 will not be flashed, but a circuit willbeestab- 'lished from secondary .19 through leads 2U, 23, and25, switch-M11, open switch E11 fromcontact, an to back contact c1'1, lead 26 toswitch E11, which is closed; thatfis, contactsd21 andb'ziare bridged, which will cause code symbol 670 to ,b'eflashed instead of 257. Code symbol 670, set up in the third bank, is thus repeated in the cycle, by the impulse switch M11 whichfis freed by the now idle second bank (in which ment this is illustratively once'for every cycle of group of keys and selective circuits is thus no longer idle, and that condition prevents its normally allocated impulsing switch M21 from being allocated to some other bank'or group;of keys and circuits. When impulsing unit I closes switches M1 and M11, the action will be as above, that is, first code symbol 146 will flash as a result of'operation of its normally allocated impulsing switch M and only during that portion I of the cycle allocated to that switch, *andthen code symbol f257 is flashed "under the control of switch M11 normally allocated to the group in which thecodesymbol 257? is set up and'for the portion of the cycle allocated to the closure of switch M21. Code symbol 146 will 'n otnow flash when switchl/I21 is closed becauselthe circuit accomplishing that is now open from con-' tact a21' to contact 021 Instead, when-switch .257f had been set up) and Whichjin response to that idle condition, is now allocated to serve the third bank. Thus the code symbols will be flashed in the. following order; 146, 670," 670,? 146, 670. A reallocation of the im pulsing switches, per cycle, and of thepulses or signalling intervals available in'the cycle, has thus taken place. 1

Recurring to the circuits generating the audible signal, this circuit, as. above stated, comprises switch Mlifswitch A, and relay winding AR connected across secondary. i9. Switch A is manually operated when an audible signal is desired to be given to call attention in that manner, to the actuation of the visual or flashing signals,

and the closure of switch A permits the circuit l of relay AR to be closed every time impulsing' unit I closes switch MA. -In the present embodie operation ofthe system, but may be changed if so desired. No audible signal is transmitted unless at least one of the starting keys S1, S11,

or S21 is depressed because, unless that is the case, the motor circuit is open at switches F1, F11, and F21, which, as above stated, are'con-f trolled by starting keys S1, S11, and S21,re--

' spectively.

In Fig. 2 switches F1,,F11, and are shown asthree switches in parallel and if anyone of theseis' closed, current will be fed to synchro-Q nous motor SM and the system will operate in repeated cycles. Although shown in this'fi'nian ner,=in actual practice switches F1, F11, a'iid' Fmmay be either separate switches each operated bystarting keys S1, S11,and S21, respectively, or may be a single switch'kept in its closed position whenever any. one of the starting keys S1,, S11,

orSiu is'depressed. The mechanical design of sensor switches FILLED. an Fit ma aksan ililf ab e formr Y Y 'Ihe oper ti n oi he. ys em i lnst ativol described above in connection with ,an illustrative capa ity o thre d erent and uccess v i nol transmissions per c cl will o oon.:.to orers efficient in that it is-possible to avoidwaste of time, loss of signal transmission where less than the full ca acity of signals is set up on the several rows or banks of digit selecting keys and switches, and that the system automatically aohieyes. d ter ina n o wha a t va d rs lected signal is to be repeated in those portions of the cycle left idle by a de-activatedselector circuit; to the matter of such repetition, the operator; need give no concern- Moreover it will be seen that these advantages'can v be accomplisned w h co pa u o p c ted a d, expensive and long-lasting devices andcircuit arrangements. Where large numbers of combinations, of digits or the like are to be selectively set up by the utilization of digits common. tQtwo ormore of the groups of selector circuits, un-f desirable multiplication of circuitand circuitmakers and breakers can be avoided by the use of. unidirectional conductive devices, such as rectifiersin the circuits, asin the relay winding selectorcircuits to prevent the undesired return otcur-rent from return leads 2;2. -and 2,4,through the relay windings and pilot lamps. Assuming, for example, that the keyboard is setup to send threecode symbols, 146, '7, and 6'10, that these rectifiers are not in the circuit, and that switch M1. is closed, circuits will be established from secondary 19' through leads 20 and 23,

. switch Mnand switch E1 from (11 tob and thence and relay winding Ra. Thus, without rectifiers inthe circuit, thefalse code symbol 1245670? would be flashed when switch M1 is closed and similarly whenswitch M11 or M21 is closed.

The illustration just given shows the conditions that exist when the full capacity of the system isused, illustratively to transmit in. sequence three code symbols set up in the three banks of parallel circuits; the valves or rectifiers, however, serve in similar manner to prevent transmission of false signals when less than the full capacity of the system is employed, in which case, typified in several illustrations earlierabove set forth, a sig'nal set up on one bank of selector circuits is also transmitted, and hencerepeated during the cycle, at the pulsing switch contact through which theotherwise idle bank of selector circuits would be actuated. In such cases electri cal energy, as fromthe transformer T,jis supplied to the active valved or rectifierrcontaining parallel circuits through the back contactv or contacts, and their respective connections, of that one or more group-selector switch that is inactive. or in at-rest position, a positionin which its-back contact takes part in supplying energy to'the valved parallel circuits. 7 The valves or rectifiers thus coact alsoin the energizing cira :14 Qu t Waters e tablished at. he boo contac s of than no so o ton w he E1, E11,. En; tc. It isthus S n tha en two or mo e ode mbo s-are t u ith. a QmIQQIL. elicit the presence of rectifiers preventsa-ialse signal-i din ion. o t a sm ssion or each closure oieach pulsin swi ohszi this manner omplicat d oom-. m iat r s stems an .ninltino. ......e1ays. need not DQEH DlQYQFL man oss ble. emlood -monts may Joel made Faiths. abov inv ntion andas. many. changes mi h be made. in he. embodiments set forth abovoiit. isto be understood that. allmatter here-i inbefore s t f rth or showninitne accompanying rawin into. be..; nternreted as illustrative and not ina.Jim.itin' wsense.v i olairnr. or j I .an lectrically-operated pa ing system forselectivelyproducing cyclically: signalling code sym ols-and.- ii r; producing one or more, of..- the I the, respective contacts ofv a means. operatinginrecurring cyclesitonefiect make+and'-br'eak at saidcontacts. in sequence whereby" to activate .asaid groups. in. sequence. during each cycle upon: 'clo sure of all of said group-selector switches, eachof. the latter having: anormally closed backcontact at whiclr'acircuit remainslclosediithe selector switch .is: not actuated, said back contacts being connected respectively tosaidfirst-men tioned cohtactslwith the connection'from the back:.

contact of any one. group=selector switch leading to a-contact other than thatot'o Which sa-icl group.-= selector switch is connected whereby when-' all of said groupeselector switches are-closed:and thecircuits at their respective back 7 contacts are opened veach code symbol is. produced once, and all-of them insequence, for each CyC1 QIld l; en one-or 'nicre: but not all ofisaid group selea switches is in open position to eifect-ci-r-cuit sure'at its back contact, the code t-sym bol' producedas the result of a closed selector switch 'is repeated during each cycle of said systeml- 2. I'n anelectrically-operated pagingsystem capable of producing on indicators. during-one cycle of operation of saidsystem at least three code symbols-in sequence eachof which is madeup of a selection-from alarge number ofv possible code symbols, a group of parallelcircuits for each of said three code symbols, each-"group of par allel circuits connectedat one endto said-indicators and at the other ends connected to .re-

spective group selector switchesand; through a group-selector switch for connecting ;the contact normally in circuit with, it" andits; group; into the circuit 01? a closed group-,selector-switch' and its groupof parallel circuits whereby when'fall of said group-selectorf switches are; infclosed posi;-'

tion, each of said three code symbols is produced once on's'aid indicators. during a cycle of operation of said system, WhCH'tWO' ofsaid group selec tor switches; are, in closed position and the third inyopen position, two of :said ,three; codeysyinbols are, produced QIljSaid indicatorsgone being pro.- uoedtw oe andgono eing pr du edonce, duringa yoloioiioperati n of said. system, andqwhen say one of said groupselector switches is'i'in 3.-'A switching arrangement for apagin'gsys tem of the classdescribed comprising a plurality of banks of operating circuits and .a plurality of single-pole double-throw switches having each of their closed-position contacts respectively connected to said banks of operatingcircuits and having each of their fixed contacts connected to the open-position contact of at least one of the other of said switches.

4. A switching arrangement for a paging system of the class described in-which three code symbols may be signalled during one cycle of operation of the system comprising three banks of operating'circuits and three'single-pole double-throw switches having their closed-position contacts connected respectively to said banks of operating circuits and having the fixed contact of the first of said switchesconnected to the open-position contact of the third of said switches, the fixed'contact of the'second of'said switches connected to the open-position contact of the first of said'switches-and the fixed contact of the third of said switches connected to the open-position contact of the second of said switches.

5, Aswitohing arrangement for a paging system of the classidescribed comprising a plurality of groups of operating circuits, circuit-controlling means having aplurality. of circuit-making- ,and-breaking devices, one for each of said groups of operating circuits, and operating in recurring cycles to actuate said devices in sequence during each cycle, a plurality of group-selector switches, one foreach of said groups of circuits, and circuit connections and circuit controlling devices connecting the circuits of said group-selector switches in ,circuit respectively with said circuitmaking-and-breaking devices when, all .of said group-selector switches are actuated sojthat said groups of circuits are activated in sequence during each cycle and, when one or more but not all of said group-selector switches are not actuated so as to free one or more of said circuit-makingand-breaking devices, connecting the circuit of an actuated group-selector switch in circuit also with, one or more idled circuit-,making-andbreaking device and thereby eliect activation of the-circuit of the actuated group-selector switch more than once during each cycle.

,6, In an electrically-operated paging system,

a plurality of selectible signalling circuits, a cyclically-operating circuit-controlling device that closes and opens sequentially at a plurality of contacts of which there is one for each of said selectible signalling circuits, and a plurality of selector. switches, one for each of said selectiblesignalling circuits and each havinga normally open front contact and a normally closed back contact, said selector switches connecting said signalling circuits respectively to said plurality of contacts of said circuit-controlling device through their respective front contacts whereby when all of said selector switches are actuated to close at their front'contacts and openat their back contacts said signalling circuits" are activated in sequence during each cycle and said selector switches having their back contacts connected respectively to said plurality of contacts of said circuitcontrolling device" in phase-displaced order relative to the ordef'of connection thereto of said selector switches whereby when 16 one or more but not all of said selector switches is in unactuated position and is closed atthe back contact, the signalling circuit of an actuated selectorswitch is additionally activated by another one of said plurality of contacts of said circuit-controlling device through a circuit including said closed back contact.

7; In an electrically-operated paging system for selectively producing cyclically signalling code symbols and for producing one or more of the'selected code symbols during each cycle of operation of the system, a source of electric energy,a plurality of signalling circuits to be. en-

, ergized thereby and all of them connected at one contacts of which there is one for each of said groups of selector circuits, said circuit-controlling device having means operating it in recurring .cycles, means for supplying electrical energy from said source to said signalling circuits through said sequentially-operated contacts comprising a plurality of group-selector switches, one for each group of selector circuits, whereby, upon actuation of all of said group-selector switches, energy is supplied to said signalling circuits sequentially through said grou'ps'of se lector circuits during each cycle, said plurality of contacts having auxiliary circuit connections leading respectively to saidgroups of selector circuits with switching means in each, and control means for said switching means adaptcd'to be actuated when a group of selector circuits and its corresponding one of said plurality-of contacts are idle, for completin an energizing circuit through'said idled contact to an active group of'selector circuits whereby the latter is additionally energized during each cycle;

8; In an electrically-operated paging system for selectively producing cyclically signalling code symbols and for producing one .or more of the selected code symbols during each cycle of operation of the system, a source of electric energy, -a plurality of signalling circuits to be energizedthereby and all of them connected atone end to'one side of said energy source and to the other ends of which are connected the respective parallel-connected ends of a plurality of groups :rality of group-selector switches, one for each lector circuits, having circuit connections respec group of selector circuits, whereby, upon actuation of; all of said group-selector switches, en- =ergy is supplied to said signalling circuits sequentially through said groups of selector cir-- cuitsrluring each cycle, and a plurality of switch- ;ing means, one for each of said groups of se- 'tively to said plurality of contacts in phase-dis- ;placed order relative to the order in which said plurality of contacts are respectively connected :to said groups of selector circuits by their respective group-selector switches, each of said switching means having a control means therefor that is responsive to active and inactive condition of its group of selector circuits whereby, when less than all of said groups arev active, thus making idle one or more of said plurality of contacts, an idle contact is connected in circuit with an active group of selector circuits.

9. An electrically-operated paging system comprising a plurality of selectible signalling circuits, a source of electrical energy for energizing said circuits, means for controlling the energization of said signalling circuits from said source comprising a circuit-controlling device that closes and opens the circuit at a plurality of contacts, one for each signalling circuit, in a sequence A A A A, said circuit-controlling device having means operating it in recurring cycles for repeating said sequence, a plurality of selector switches, one for each of said signalling circuits and each having a normally open front contact and a normally closed back contact, having their front contacts connected respectively to said signalling circuits and connecting the latter to said plurality of contacts of said circuit- 18 controlling device for energization, upon closure of all of said selector switches at their front contacts, in the sequence A A A A and electrical connections respectively from the back contacts of said selector switches to said plurality of contacts of said circuit-controlling device and arranged in the sequence A A A ,v

JOHN E. KREINER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name I Date 1,780,711 Lichter Nov. 4, 1930 1,795,536 Baker Mar. 10, 1931 2,302,535 Durbin Nov. 17, 1942 2,481,269 Welch Sept. 6, 1949 2,507,744 Welch May 16, 1950 FOREIGN PATENTS Number Country Date 499,900 Great Britain Jan. 31, 1939

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