US2484612A - Directory number calling line identifier - Google Patents

Description

J. W. DEHN ETAL DIRECTORY NUMBER CALLING LINE IDENTIFIER 4 Sheets-Sheet l Filed May 17, 1946 .j W DEHN THQ/ DEN /N VEN TO/QS ATTORNEY ct. 1l, 1949. J. w. DEHN ErAl.

DIRECTORY NUMBER CALLING LINE IDENTIFIER 4 Sheets-Sheet 2 Filed May 17,` 1946 WENN /M/ENTORS @y ATTORNEY Oct. 11, 1949. Q1. w. DEHN ETAL DIRECTORY NUMBER CALLING yLINE` IDENTIFIER 4 SheeS-Sheet 3 m. dbx

Filed May 17, 1946 +Mw q J. W DEH/v Nl/Mops W r HOL 05N ATTORNEY Oct. 1l, 1949.

J. w. DEHN ETAL DIRECTORY NUMBER CALLING LINE IDENTIFIER 4 Sheets-Sheet 4 Filed May 17, 1946 ATTORNEY Patented Oct. Il, 1949 DIRECTORY NUMBER CALLING LINE IDENTIFIER Joseph W. Dehn, Great Neck, and William H. T.

Holden, Woodside, N. Y., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application May 17, 194e, serial No. 670,358

20 Claims.

This invention pertains to telephone systems and more particularly to systems for identifying calling lines to determine their directory numbers. Calling-line-identiiying devices are necessary in connection with the automatic recording of telephone calls and it is desirable, for this purpose, that calling lines be identified by their directory numbers rather than by terminal numbers, to avoid the further operations necessary to obtain the directory numbers for billing purposes. Identification of lines by their directory numbers presents diiiiculties, particularly in systems of the cross bar type where there is no direct relation between the terminal number or physical location "of a line and its directory number. The present invention discloses an economical and simple system for obtaining the directory numbers of calling lines directly and rapidly; While particularly valuable in connection with cross bar systems, it is not limited in its application to systems of that type nor to the purposes of automatic message recording, but is applicable to any type of telephone system and to any purpose for which it is desirable to ascertain the directory numbers of calling lines.

A feature of this invention is the use of electronic devices, which are inexpensive, not subject to rapid deterioration, and readily replaceable.

Another feature of the invention is the use of a unidirectional pulse of extremely short duration to effect identification, with the consequent saving in time and equipment. The pulse may be extremely short because the indicating devices responsive to said pulse are affected by the rate of change of the pulse as it increases from zero to its maximum value rather than by the specic magnitude of the pulse.

Another feature of the invention is an arrangement Iwhereby a plurality of identiiiers may each be connected for identification of calling lines at any time without interfering with one another.

Another feature of the invention is a novel form of pulse generator for actuating identiiiers of the type disclosed.

Still another feature of the invention is the use of equipment' to serve a large number of subscribers lines, not only in one central office but, if desired, in a plurality of central oflices.

These and other features of the invention will be apparent from the following description, the appended claims, and the drawings, in which:

Fig. 1 shows two subscribers lines, the extension of one of said lines by switching means, and a portion of the common circuit networks provided for identifying these and other lines;

Fig. 2 shows another portion of the common circuit networks;

Fig. 3 shows the circuit of an identiiier;

Fig. 4 shows circuits for actuating a plurality of identifiers;

Fig. 5 is a graphical representation of the potentials supplied to a pulse generating tube shown in Fig. 4; and

Fig. 6 shows how the above iigures (except Fig. 5) should be placed with relation to one another to disclose the invention.

We will first describe the arrangement of the comino-n circuit networks provided for identification purposes, from which description the general mode of operation of the invention will be apparent. For the purpose of illustration, two subscribers lines II and I2 are shown in Fig. 1 and it is assumed that both of these lines are in the same central oliice, designated oiiice No. 1, and that the directory number of line II is 5238, while that of line I2 is 4167.

In accordance with the present invention, the sleeve conductor of each subscribers line the directory number of which may be required to be identified is connected to one element of each of two gas-discharge cold cathode tubes. For example, the sleeve conductor I3 of line II is connected to one element of each of tubes I5 and I6, while the sleeve conductor I4 of line I2 is connected to one element of each of tubes I1 and I8. The other element of each of the tubes assoi ciated with each line is connected to one of common conductors or bus-bars,.in accordance with the thousands and hundreds digit combination of the directory number of said line. For example, bus-bars THUU, THM, TH52 and THSS are four of the 100 bus-bars provided for oflice No. 1 in which lines I I and I2 are located, and are the bus-bars assigned to the thousands and hundreds digit combinations 00, 41, 52, and 99, respectively. Accordingly, an element of tube I5, associated with line II the directory number of which is 5238, is connected to bus-bar TH52, to which are also connected corresponding elements of tubes associated with other lines (not shown) in the same central oiiice having directory numbers the thousands digit of which is 5 and the hundreds digit of which is 2. Likewise, an element of tube Il, associated with line I2 the directory number of which is 4167, is connected to bus-bar PTHII, to which are also connected elements of tubes associated with other lines (not shown) in the vsame central oiiice having directory numbers the thousands digit of which is 4 and the hundreds digit of which is 1.

To each of the thousands-hundreds-digits busbars-THU!) to TH99 is connected one element of each of three gas-discharge cold cathode diode tubes. For example, one clement of each of tubes i9, 20, and 2l is connected to bus-bar 'FI-199, one clement o each of tubes 22, 23, and 24 is connected to bus-bar TH52, one element of each of tubes 25, 26, and 21 is connected to bus-bar THM, and one element of each of tubes 2B, 29 and 30 is connected to bus-bar THUD. The other element of onc l the tubes connected to each thousandshundreds-digits bus-bar is connected to a bus-bar individual to the central cnice served by said thousands-hundreds-digits bus-bar. For example, one element of each of tubes I9, 22, 25, and 28 is connected to bus-bar OFFI, which is individual to oce No. l.

The other element of the second of the tubes associated with each thousands-hundreds-digits bus-bar is connected to one of thousands-digit bus-bars THU to THS in accordance with the thousands digit of the thousands-hundreds-digit combination, while the other element of the third tube associated with each thousands-hundredsdigits bus-bar is connected to one of l0 hundreds digit bus-bars H0 to H9 in accordance with the hundreds digit of the thousands-hundreds-digit combination. For example, one element of tube 23, associated with bus-bar TH52 assigned to the digit combination 52, is connected to bus-bar THS, to which are also connected corresponding elements of tubes associated with other thousands-hundreds-digits bus-bars (not shown) assigned to digit combinations the rst digit of which is 5. sociated with bus-bar TH52, is connected to busbar H2, to which are also connected corresponding elements of tubes associated with other thousands-hundreds-digits bus-bars (not shown) assigned to digit combinations the second digit ..1

of which is 2.

The thousands-hundreds-digits bus-bars are each supplied with negative potential, for example, from battery BI through resistances 3l, 32, 33, and 31S, and each of the ofiice, thousandsdigit and hundreds-digit bus-bars are supplied with a higher negative potential, for example, from battery B2 through resistance 35 to busbar OFFI. The difference of potential of batteries Bl and B2 is approximately that necessary to maintain conduction in each tube, such as tube I9, but is insuncient to initiate conduction in said tube. None of the gas-discharge diode tubes connected to the bus-bars, therefore, normally conduct but will conduct if the difference of potential between their elements is slightly increased.

It is now evident that, owing to the arrangement of bus-bars and gas-discharge tubes, if a potential is applied to the sleeve conductor of any line sufcient to cause the gas-discharge tubes connected thereto to conduct, said potential will be transmitted through said tubes to certain of the oiice, thousands-digit and hundreds-digit bus-bars, and,upon tracing the path of said transmission, it will be apparent that the particular bus-bars on which said potential appears indicate a part of the directory number of said subscribers line. For example, if a potential is applied to the sleeve conductor i4 of line l2, causing tube l1 to conduct, said potential will be transmitted through the conduction ofl tube l1 to bus-bar THM thence to tubes 25, 26 and 21, causing said tubes to conduct, and through the latter tubes to bus-bars OFFl, TH4 and Hl. If suitable indi- Likewise, an element of tube 24, as-

eating means are provided, the presence of Said potential on bus-bars OFFl, TH4, and Hl will indicate that line ll, to the sleeve conductor of which potential was applied, is in oflce No. 1, that the thousands digit of its directory number is 4, and that the hundreds digit is l.

It is also evident that a set oi thousandshundreds-digits bus-bars THSU to THSS and an oflce bus-bar. such `as bus-bar OFFI, must be provided for each central oice, since these busbars are used to indicate the central oice in which the line being identified is located, but that the thousands-digit bus-bars THD to THS and the hundreds-digit bus-bars H0 to H9 may be used to serve the lines of any number of central oiiices, since these bus-bars are used only to indicate digits of directory numbers.

A similar arrangement of bus-bars and gasdischarge tubes is used tto indicate the tens and the units digits of directory numbers. The other element of the above-mentioned second gas-discharge diode tube associated with the sleeve conductor of each subscriber's line is connected to one of 100 tens-units-digits bus-bars, of which bus-bars TUBO, TU38, TUM and TU99 are four, in accordance with the tens-units-digits combination of the directory number of said line. For example, an element of tube I6 associated with line Il the directory number of which is 5238, is connected over conductor 36 to bus-bar TU38, to which are also connected corresponding elements of tubes (not shown) associated with other lines the directory numbers of which coinprise the tens-units digit combination 38, while an element of tube I8, associated with line l2 the directory number of which is 4167, is connected over conductor 31 to bus--bar TU61, to which are also connected corresponding elements of tubes (not shown) associated with other lines the directory numbers of which comprise the tens-units digit combination 67.

To each of the tens-units-digits bus-bars TUBO TUBE is connected one element of each of two gas-discharge cold cathode diode tubes. For example, one element of each of tubes 38 and 39 is connected to bus-bar TUSS, one element of each of tubes 4U and 4| is connected to bus-bar TUGl, one element of each of tubes 42 and 43 is connected to bus-bar TU38, and one element of each of tubes 44 and 45 is connected to bus-bar TUUO. The other element of one of the tubes associated with each tens-units-digits bus-bar TUBO TUSS is connected to one of l0 tens-digit busbars T0 T9 in accordance with the tens digit of the tens-units-digits combination, and the other clement of the second tube associated with each tens-units-digits bus-bar is connected to one of l0 units-digit bus-bars U0 U9 in accordance with the units digit of said combination. For example, an element of tube 40 associated with bus-bar TUBT, assigned to the digit combination 67, is connected to bus-bar T6, to which are also connected corresponding elements of tubes (not shown) associated with other tensunits-digits bus-bars assigned to digit combinations the tens digits of which is 6, and an element of tube 4l, also associated with bus-bar TUST, is connected to units bus-bar U1, to which are also connected corresponding elements of tubes (not shown) lassociated with other tensunits-digits bus-bars assigned to digit combinations the units digit of which is 7. Each bus-bar is supplied with suitable potential, the tens-unitsdigits bus-bars NUOD TUSS with negative potential from battery B3 through resistances,

such 'as resistance 48, and the tens-digit and units-digit bus-bars T T9 and U0 U9, respectively, with higher negative potential from battery B4, through resistances such as resistance 41, such-that the gas-discharge diode tubes connected to said bus-bars do not normally conduct but will conduct if :the potential dilerence between their elements is slightly increased.

It is evident that if a potential is applied to the sleeve conductor of any line suilicient to cause the gas-discharge tubes connected thereto to con duct, said potential will be transmitted through said tubes to certain of the tens-digit and unitsdigit bus-bars and the presence of potential on those bus-bars will indicate the tens and units digits of the directory number of said line. For example, if potential is applied to sleeve conductor I4 of line I2, causing tube I8 to conduct, said potential will be transmitted through said tube, over conductor 31 to bus-bar TUBI, thence to tubes 48 and 4I, causing said tubes to conduct, and through said tubes to bus-bars T6 and U1, indicating that the tens and units digits of the directory number of line I2 are 6 and 7, respectively.

It is also evident that the tens-units-digits busbars TUll TU99, the tens-digit bus-bars T0 T9, and the units-digit bus-bars U0 U9 may be used to serve any number of lines located in any number of central oices since they are employed to indicate digits of directory numbers of lines irrespective of the central offices in which said lines are located.

By the use of additional bus-bars and additional gas-discharge tubes connected in the manner described, the system may be extended to provide means for indicating directory numbers of more than four digits or other information in regard to a line identified, such as the class of the line or its rate zone.

For utilizing the means provided by the common circuit networks for the ldentication of calling' lines, an identifier circuit (shown in Fig. 3) is employed which comprises an indicating tube and an associated registering tube connected through a condenser, to each of the oiice, thousands-digit, hundreds-digit, tens-digit, and units-digit busbars, a pulsing tube, and registers for the office number and for each of the four digits of the directory number. For example, tube 48 is an indicating tube and tube 49 a registering tube associated with thousands-digit bus-bar TH5; tube 50 is an indicating tube and tube 5I a registering tube associated with hundreds-digit busbar H2; tube 52 is an indicating tube and tube 53 a registering tube associated with tens-digit busbar T3, while tube 54 is an indicating tube and tube 55 a registering tube associated with units-l digit bus-bar U8. Tube 56 is the pulsing tube of the identifier comprising the above-mentioned indicating and registering tubes and the other indicating and registering tubes associated with each of the digital bus-bars THU THS; H0...H9;T0...T9andU0...U9. Inthe present embodiment of the invention, the indicating tubes and the registering tubes are gasdischarge 'triode tubes of the cold cathode type and the pulsing tube is a gas-discharge tetrode tube of the heated cathode type. The registers may be of any suitable type and may each be similar to the register for the units digits, comprising relays R0, R8, R9, CK, and ON, disclosed in Fig. 3.

The control anode of each of the indicating tubes, for example, tube 54, is supplied with positive potential by positive battery through resistances,51 and 58 and this potential is of such value that said tube will not normally conduct even when its main anode is also supplied with positive potential, but will conduct if, at the same time, the potential of its control anode is slightly raised. The main anodes of all the indicating tubes of Aan identiiier, such as tubes 48, 50, 52 and 54, are connected to the cathode of the associated pulsing tube, in this case, tube 56. The anode of the pulsing tube 56 is supplied with alternating po tential from the source 59 through transformer 60. The control grid of said tube is biased by negative battery through resistance 6I so that said tube doe's not normally conduct, but will conduct if the potential of its control grid is made slightly less negative. The main anode of each of the registering tubes, for example, tube 55, is

supplied with positive potential and the control anode biased by potential from the voltage divider composed of resistances 62 and 63, so that said tube does not normally conduct but will conduct if its control anode is made slightly more positive. Y

To identify a calling line, for example, line II extended by line link 64, district link 65, and oiice link 66, the cathode of the pulsing tube of an identier, for example, tube 56, of the identier shown in Fig. 3, is connected through resistance 61 and conductor 68 to sleeve conductor I3 of said line, as extended, at any convenient point in the partially established connection by suitable means, such as relay SI or relay S2. The control grid of tube 56 is then made, by suitable means such as that hereinafter described, momentarily suiciently less negative to cause said tube to conduct during the positive half of one cycle of alternating current.

The sleeve conductor of a subscribers line, for

example, conductor I3, is used in automatic telephone systems for other purposes, chief among which is the holding of the magnets of the various switches by which the line is extended. Rectifier 69 provides a path to ground for the negative potential by which said magnets are held but opposes the passage of positive potential. The positive pulse from the cathode of tube 56 will not,` therefore, pass through rectifier 69 but will be transmitted over conductor 63 through contacts of relay SI or relay S2 to sleeve conductor I3 as extended and to tubes I5 and I6, causing said tubes to conduct, thence by the conduction of tube I5, to bus-bar TH52 and by the conduction of tube I6, to bus-bar TU38. The pulse of positive potential on bus-bar TH52 will cause tubes 22, 23, and 24 to conduct and, by the conduction of tube 22, will be transmitted to bus-bar OFFI, by the conduction of tube 23, to bus-bar TH5, and by the conduction of tube 24, to bus-bar H2. Likewise, the positive pulse on bus-bar TU38 will cause tubes 42 and 43 to conduct. By the conduction of tube 42, said positive pulse will be transmitted to bus-bar T3 and, by the conduction of tube 43, to bus-bar U8.

The positive pulse on bus-bar U8 will be transmitted over conductor 'I0 and will produce, through condenser 1I a pulse, the magnitude of which will depend upon the rate of change in potential of the pulse applied to said condenser. The pulse from condenser 1I will be transmitted through resistance 51 to the control anode of tube 54, causing said tube to conduct momentarily since, at the same time, a pulse of positive potential is received on the main anode of said tube from the cathode of tube 56. The rise of potential at the cathode of tube 54, due to the conduction of said tube, will be transmitted through condenser 12 to the control anode of tube 55, causing tube 55 to conduct over a circuit extending from positive battery, through the anode-cathode space of tube 55, resistance 13, No. 1 normal contact of relay R8, and the winding of said relay to negative battery.

In like manner, the positive pulse on bus-bars OFFI, THS, H2, and T3 will cause conduction 55,-may be registered by means of a relay circuit such as that shown in Fig. 3 for registering the units-digit indication. Only three register relays R0, R8 and R8 are shown, but it will be understood that the circuit comprises 10 such relays, each connected to a corresponding register tube in the manner shown for relay R8 and tube 55.

The current which normally flows from positive battery through resistances 62, 53 and 13, No. l normal contacts of relay R8, and the winding of said relay to negative battery is not sufficient to operate relay R8. When tube 55 conducts, however, as described above, the decreazcd resistance in the circuit causes additional current to ow, operating relay R8 which locks up through its own No. 1 front contact and No. 2 contacts of normally-operated relay ON. The operation of relay R8 opens at the No. 1 normal contact, the circuit of tube 55, causing said tube to cease to conduct and, at the No. 3 back contact of said relay, opens'the normal operating circuit of relay ON, which extends from batter through the winding of relay ON, and No. 3 back contacts of relays R to R9 inclusive, (relays R8, R8, and R9 only being shown) to ground. However, relay CK now operates over a circuit extending from battery through the winding of said relay, No. 2 contacts of relays RD to R1 (relay RD only being shown), No. 3 front contact of relay R8 and No. 3 back Contact of relay R8 to ground, providing an obvious additional circuit through its contacts for relay ON which prevents release of relay ON.

If, through some fault in the circuits, more than one of the register relays R0 lto R9 are operated at the same time, the circuit of relay CK will not be completed. Relay CK will, therefore, not operate and relay ON will release. A circuit will then be completed from ground through back contact of relay CK and No. l contacts of relay ON to an alarm (not shown) actuating said alarm.

A plurality of identifiers of the type described may be associated with the same bus-bars in the manner described for the identifier comprising the tubes shown in Fig. 3. If the respective pulsing tubes 56 of these identifiers are actuated repeatedly and in succession, no two pulsing tubes being actuated at the same moment, then any or all of said identifiers may be connected to calling lines for identification at the same time and each identifier will identify the line to which it is connected. For example, assume two identiers to be associated with bus-bars U0 to U9. Then to each of bus-bars U0 to U9 will be connected two indicating tubes similar to tube 54 and in the manner shown for tube 54. The main anode of one of said tubes associated with each bus-bar will be connected to the cathode of a pulsing tube, similar to tube 56, of a first identifier, while the main anode of the other of said tubes associated with each bus-bar will be connected to the cathode of a pulsing tube, similar to tube 59, associated with the second identifier. 1f the cathode of said first pulsing tube be connected to the extended sleeve conductor of a line having a directory number the units digit of which is 6 and the cathode of said` second pulsing tube be connected to the extended sleeve conductor of a line having a directory number the units digit of which is '1, and the two pulsing tubes be energized in succession, a positive pulse will appear on bus-bar U6 when said first pulsing tube is energized and will reach both indicating tubes connected to said bus-bar, while a positive pulse will appear on bus-bar U1 when said second pulsing tube is energized and will reach both indicating tubes connected to bus-bar U1. But the firstmentioned positive pulse will affect only the iirst of the two indicating tubes connected to bus-bar U6, since the main anode of said tube is, at the moment, supplied with potential from the cathode of said iirst pulsing tube, while the main anode of the second indicating tube is not supplied with potential. Likewise, the second-mentioned positive pulse will affect only the second of the two indicating tubes connected to bus-bar U1, since the main anode of said tube is, at the m0- ment, supplied with potential from the cathode of said second pulsing tube, while the main anode of the first indicating tube is not supplied with potential, In like manner, other indicating tubes, and consequently the associated registering tubes, are aiected by pulses produced by the associated pulsing tube but are unaffected by pulses produced by the pulsing tubes of othe:- identifiers.

A circuit arrangement for actuating identifiers in rapid succession for the purpose described above is shown in Fig. 4. It includes a pulse generating tube 14 and a circuit of the type known as a thyratron ring, comprising tubes 15, 18, 11, and 18. This circuit is arranged for actuating four identiiiers but, by extention of the thyrairon ring, may be adapted to the actuation of any number of identifiers.

One winding of transformer is supplied with alternatlng current over conductors 8| and 82 through transformer 60 from the same source 59 which supplies anode potential to tube 56 and to pulsing tubes (not shown) of three other identifiers to be actuated. Alternating potential from the other winding of transformer 80 is biased by negative potential from the voltage divider composed of resistances 83 and 84 and supplied to the network composed of resistance 85 and condenser 86, the values of which are so chosen that the potentials at rectifiers 81 and 88 have a phase difference of nearly but not exactly degrees. Curves A and B in Fig. 5 show graphically the relative potentials applied to rectifiers 81 and 88, respectively. Said rectifiers are poled so that they oppose transmission of positive potentials. |I'he resultant potential transmitted through rectifiers 81 and 88 and thence through resistance 89 to the control grid of tube 14, which, in the present embodiment of the invention is a gas-discharge triode tube of the heated cathode type, is shown by the heavy line curve of Fig. 5. It will be observed that said control grid is maintained sumciently negative l to prevent conduction in tube 14, except during a short period in each cycle when its potential approaches zero suiiiciently to permit tube 14 to conduct. The anode of tube 14 is supplied with voperating potential through the self-clearing anode circuit comprising resistance 90 and condenser 9|, the values of which are so chosen in relation to the valueof the anode potential and the characteristics of tube 14 that the discharge of condenser 9|, due to the drop of potential through resistance 90 when tube 14 conducts, maintains conduction until the control grid of tube 14 again goes negative, when the potential between the main anode and the cathode of said tube is insufficient, due to the potential drop in resistance 90, to maintain conduction.

Tube 14, therefore, conducts for a very short period in each cycle of alternating current, producing, at its cathode, short positive pulses which are transmitted through resistance 92, thence through condensers 93, 94, 95, and 96 and resistances 91, 98, 99 and |00 to the control anodes of the gas-discharge cold cathode triode tubes 15, 16, 11 and 18. The control anodes of said tubes are each negatively biased. For example, the control anode of tube 16 is biased by negative battery through resistances |02, and 91. The amplitude of the pulses from the cathode of tube 14 is limited by rectier |03 to a value insufficient in itself to overcome said negative bias and cause tubes 15, 16, 11, and 18 to conduct. Upon the closure of switch |04 to apply anode potential to tubes 15, 16, 11 and 18 the sudden rise of potential at the main anode of tube 15 is transmitted through condenser to the control anode of said tube, said rise of potential in addition to a positive pulse received at said control anode from the cathode of tube 14 being suflicient to cause tube 15 to conduct. A part of the resultant rise of potential at the cathode of tube 15, the amount being determined by the voltage divider composed of resistances |0| and ||0 is, however, transmitted through the network composed of resistances |02 and 91 and condenser with a time delay due to the characteristics of said network, to the control anode of tube 16, raising the potential of said control anode so that the additional potential of the next positive pulse from the cathode of tube 14 is sufiicientto cause tube 16 to conduct. The resultant sudden rise of potential at the cathode of tube 16 is transmitted through condenser |06 to the cathode of tube 15` raising the potential of said cathode to a point where tube 15 ceases to conduct. A part of said rise of potential at the cathode of tube 16, the amount being determined by the voltage divider composed of resistances ||2 and H3, is transmitted through the network composed of resistances ||4 and 98 and condenser ||5 with a time delay due to the characteristics of said network to the control anode of tube 11 so that, upon receipt of the next positive pulse from the cathode of tube 14, tube 11 conducts, causing conduction in tube 16 to cease and preparing tube 18 for conduction on the next pulse from tube 14 in the manner described for tube 16.

This action is repeated, tubes 1B, 157 16, 11, 18, conducting in succession indenitely.

.Each time tube 18 conducts, a positive pulse is produced at the cathode of said tube which is transmitted over conductor |6 to the control grid of pulsing tube 56 individual to the identiiier shown in Fig. 3, actuating said tube in the manner previously described, and each time tubes 15,

16 and 11 conduct, positive pulses are produced at the cathodes of said tubes which are transmitted over conductors ||1, H8 and ||9, respectively to the pulsing tubes (not shown) of three other identifiers. The cathode of tube 56 and similar pulsing tubes of said other identifiers, need only be connected to the extended sleeve conductors of lines, as previously described, during a period sufcient for each ofsaid tubes to receive one pulse to identify each of said lines.

A large number of lines are dependent for identiiication upon the potentials supplied to the busbars for actuating the gas-discharge diode tubes associated with them. Therefore, each bus-bar should be provided with an alarm circuit to give immediate warning of the failure of any of said potentials. Suitable alarm circuits are disclosed in Fig. 2. Each of the thousands-hundredsdigits bus-bars and each of the tens-units-digits bus-bars may be provided with an alarm circuit similar to that shown, as an example, associated with bus-bar TU61. The main anode of tube |20 which, in the present embodiment of the invention is a gas-discharge triode tube of the cold cathode type, is supplied with alternating potential from the source |2| through the winding of relay AI, while the cathode of said tube is supplied with positive potential directly applied thereto. The diierence of potential between the anode and the cathode of tube |20 is at no time sufiicient to initiate conduction in said tube but is suicient to maintain conduction on negative cycles of alternating current. Negative potential applied through resistance 46 to bus-bar TU61, thence through resistances |22 and |23 to the control anode of tube |20 causes said tube to conduct on negative cycles of alternating current, operating relay AI. The discharge of condenser |24 through resistance 22 maintains the control anode of tube |20 sufiiciently negative when positive pulses are received on bus-bar TU61 so that tube 20 does not cease to conduct during the period of said pulses. If, however, the negative potential through resistance 46 should fail, tube |20 will cease to conduct, releasing relay AI, which completes a circuit to an alarm (not shown) actuating said alarm.

Each of the oiilce, thousands-digit, hundredsdigit, tens-digit, and units-digit bus-bars may be provided with an alarm circuit similar to that shown, as an example, associated with bus-bar U0. Tube |25, which in the present embodiment of the invention is a gas-discharge triode tube of the cold cathode type, is supplied with anode potential in a manner similar to tube |20, its cathode being connected to ground. Negative potential through resistance 41 to bus-bar U0, thence through resistance |21 to the control anode of tube |25 causes said tube to conduct on negative cycles of alternating current, operating relay A2. Positive pulses received on bus-bar U0 are insuiiicient to overcome the high potential supplied by battery B4 to the control anode of tube |25. However, should the potential through resistance 41 fail, tube |25 will cease to conduct, releasing relay A2 which completes the circuit of an alarm (not shown) actuating said alarm.

All of the tubes shown in the present embodiment of the invention are of the gas-discharge type. However, it will be apparent to one skilled in the electronic art that other forms of tubes such as vacuum tubes or other discharge devices could readily be substituted to perform the functions of the tubes described.

What is claimed is:

1. In a signaling system, a line having an identifying designation, conductors indicative of said designation, means for applying a unidirectional impulse to said line, means for directing said impulse to said conductors, and means for utilizing the change in the magnitude of said impulse on each of said conductors to register the designation of said line.

2. In a signaling system, a line having an identifying designation, conductors indicative of said designation, means for applying a unidirectional pulse of electric energy to said line, gasdischarge devices responsive to said pulse to direct said energy to said conductors, and gas-discharge devices responsive to the variation in the potential of said energy on each of said conductors.

3. In a signaling system, a line having an identifying designation composed of digits, a gas-discharge pulse generator, means for applying a pulse from said pulse generator to said line, gas-discharge devices responsive to said pulse to transmit said pulse over paths indicative of the digits of said designation, other gas-discharge devices responsive to said pulse on each of said paths for indicating the digits of said designation, and means for registering each of said indications, Y

4. In a signaling system, a line having an identifying designation composed of digits, a gas-discharge pulse generator, means for applying a pulse from said generator to said line, a rst group of gas-discharge devices associated with said line for directing said pulse over paths in aecordance With combinations of the digits of said designation, a second group of gas-discharge devices associated With said paths for directing said pulse over other paths in accordance with the individual digits of said combinations of digits, and a third group of gas-discharge devices responsive to said pulse on each of said other paths.

5. In a system for identifying telephone lines, the combination with lines each having an identifying designation, of conductors indicative of said designations, means for applying a unidirectional pulse to any one of said lines, means associated with said line for directing said pulse over said conductors in accordance with the designation of said line, and means responsive to the variation in magnitude of said pulse and common to all of said lines for registering said pulse on each of said conductors.

6. In a system for identifying telephone lines, the combination with lines each having an identifying designation, of means for applying a pulse to any one of said lines, means comprising gasdischarge devices for directing said pulse over paths indicative of the designation of said line, and means comprising gas-discharge devices for receiving and registering said pulse on each of said paths` '7. In a system for identifying telephone lines, the combination with lines each having an identifying designation, of a pulse generator comprising gas-discharge devices, means for applying a pulse from said generator to any one of said lines, a rst group of gas-discharge devices associated with said line for directing said pulse over paths indicative of the designation of said line, a second group of gas-discharge devices common to all of said lines for directing said pulse over other paths indicative of the designation of said line, and a third group of gas-discharge devices comtaneously to one of said lines and to all of said receiving devices, means for directing said pulse from said line to said receiving devices in accordance with the designation of said line. and means responsive to the change in magnitude of the pulse applied to said line for registering the coincidence at each of said receiving devices of the pulse applied to said receiving device and the pulse directed to said receiving device from said line.

9. In a system for identifying telephone lines, lines each having an identifying designation composed of digits, a plurality of gas-discharge receiving devices, means for applying a pulse simultaneously to any one of said lines and to all of said receiving devices, gas-discharge devices associated with each of said lines for transmitting said pulse, gas-discharge devices common to all of said lines for transmitting said pulse to said receiving devices in accordance with the designation of the line to which said pulse is applied, and means for registering the coincidence at each of said receiving devices of the pulse applied to said receiving device and the pulse transmitted to said receiving device from said line.

10. In combination, a plurality of lines each having an identifying designation, means for applying a unidirectional pulse to each of said lines in succession, a plurality of groups of receiving devices each responsive to the variation in the magnitude of one of said pulses, and means for directing each of said pulses to said receiving devices to indicate the designation of the line to which said pulse is applied.

11. In a system for identifying telephone lines, in combination with lines having identifying designations, a plurality of identifying circuits each responsive to the variation in the magnitude of a unidirectional impulse of short duration, means for generating such impulses, means for connecting each of said identifying circuits to one of said lines, and means for applying an impulse successively to each of said identifying circuits to indicate the designations of said lines.

l2. In a system for identifying telephone lines, in combination with lines having identifying designations, gas-discharge devices associated with each line for identifying said line, gas-discharge devices common to all of said lines for identifying any of said lines, a plurality of identifying circuits each capable of being made responsive to impulses transmitted through said gas-discharge devices from any one of said lines, means for successively making responsive each of said identifying circuits and simultaneously applying impulses to said lines, and means for registering the response of each of said identifying circuits.

13. In a signaling system, individual conductors having arbitrary designations, common conductors, and means for directing and varying the magnitude of a unidirectional impulse applied to one of said individual conductors selectively to said common conductors to identify the arbitrary designation of said individual conductor.

14. In a signaling system, individual conductors having arbitrary designations, common conductors, and electronic devices for directing and varying the magnitude of a unidirectional impulse applied to one of said individual conductors selectively to said common conductors to identify the arbitrary designation of said individual conductor.

15. In a signaling system, individual conductors having arbitrary designations, and common conductors each having an indicating device responsive to the variation in the magnitude of a unidirectional imnulse applied to one of said individual conductors and selectably directed to said common conductors to identify the arbitrary designations of said individual conductor by the operation of the indicating devices of the common conductors to which said impulse is directed.

16. In a signaling system, individual conductors having arbitrary designations, common conductors. electronic devices for selectably directing a unidirectional impulse applied to one of said individual conductors to said common conductors in accordance with the arbitrary designation oi' said individual conductor, and electronic devices responsive to the variation in the magnitude oi' said impulse to indicate said designation.

17. In a system for identification of telephone lines, lines having numerical designations, common conductors corresponding to digits of said designations. electronic devices selectablv connecting said lines to said common conductors, electronic devices interconnecting said common conductors. and means for applying a unidirectional irnpulse of varving magnitude to one of said lines to indicate the designation of said line.

18. In a system for the identification of telephone lines, a plurality of groups of lines, a common conductor corresponding to each of said grouns. electronic devices seiectably connecting said lines to said common conductors, and means for applying a unidirectional impulse of varying magnitude to one of said lines to indicate the groun of which said line is a part.

19. In a svstem for identifying telephone lines, lines having numerical designations. a rst group of common conductors for combinations of thousands and hundreds digits of said designations, a second group of common conductors for combinations of tens and units digits of said designations. electronic devices connecting said lines to said first group of common conductors in accordance with the thousands and hundreds digits of their respective designations. electronic devices connecting said lines to said second group of common conductors in accordance with the tens and units digits of their respective designations, a third group of common conductors for thousands digital values of said designations. a fourth group of common conductors for hundreds digital values of said designations, electronic devices connecting said first group of common conductors to said third and fourth groups of common conductors in accordance with -the thousands and hundreds digits respectively of said designations, a fifth group of common conductors for tens digital values of said designations, a sixth group of common conductors for units digital values of said designations, electronic devices connecting said second group of common conductors to said fth and sixth groups of common conductors in accordance with the tens and units digits respectively of said designations, and means for applying potential to one of said lines whereby certain of said electronic devices are operated to indicate the designation of said line.

20. In a system for identifying telephone lines, a plurality of groups of lines having numerical designations, a first common conductor for each combination of thousands and hundreds digits of said designations in each of said groups, electronic devices connecting each of said lines to one of said iirst common conductors in accordance with the thousands and hundreds digits of the designation of said line and the group in which said line is located, a second common conductor for each of said line groups, a third common conductor for each thousands digital value of said designations, a fourth common conductor for each hundreds digital value of said designations, electronic devices connecting each of said rst common conductors to one of said second common conductors, one of said third common conductors and one of said fourth common conductors in accordance with the line group, the thousands digit, and the hundreds digit of said designations, respectively, a fifth common conductor for each combination of tens and units digits of said designations, electronic devices connecting each of said lines to one of said fifth common conductors in accordance .with the tens and units digits of the designation of said line, a. sixth common conductor for each tens digital value of said designations, a seventh common conductor for each units digital value of said designations,` electronic devices connecting each of said fifth common conductors to one of said sixth common conductors and one of said seventh common conductors in accordance with the tens digit and the units digit of said designations, respectively, and means for applying potential to one of said lines whereby certain of said electronic devices are operated to indicate the designation of said line.

JOSEPH W. DEHN. WILLIAM H. T. HOLDEN.

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

UNITED STATES PATENTS Number Name Date 1,663,747 Bascom Mar. 27, 1928 1,690,206 Raynsford Nov. 6, 1928 1,841,084 Bragg Jan. 12, 1932 2,005,595 Roome June 18, 1935 2,084,105 Myers June 15, 1937 2,153,179 Fitch Apr. 4, 1939 2,226,459 Bingley Dec. 24, 1940 2,267,950 Rhodes Dec. 30, 1941 2,319,424 Maloney May 18, 1943

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