US2444065A - Electrical signaling system - Google Patents

Electrical signaling system Download PDF

Info

Publication number
US2444065A
US2444065A US472614A US47261443A US2444065A US 2444065 A US2444065 A US 2444065A US 472614 A US472614 A US 472614A US 47261443 A US47261443 A US 47261443A US 2444065 A US2444065 A US 2444065A
Authority
US
United States
Prior art keywords
switch
brush
detector
potential
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US472614A
Other languages
English (en)
Inventor
Willy H P Pouliart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US2444065A publication Critical patent/US2444065A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/38—Signalling arrangements; Manipulation of signalling currents using combinations of direct currents of different amplitudes or polarities over line conductors or combination of line conductors

Definitions

  • the signaling system' forming the object of this invention makes use of apparatus at both ends of a signaling wire or circuit, ,the apparatus at one end ⁇ being used-.for registering or receiving certain indications, e. g. a register controller operated in accordance with the called number, and the apparatus at the other (identiiying) end being used for the identiiication of these indications, e. g. a selector set in accordance with the setting of the register controller.
  • certain indications e. g. a register controller operated in accordance with the called number
  • the apparatus at the other (identiiying) end being used for the identiiication of these indications, e. g. a selector set in accordance with the setting of the register controller.
  • characteristic predetermined direct current poten.
  • tials are connected by the receiving apparatus or register controller to one end of the signaling circuit in accordance with the setting of the receiving apparatus.
  • apparatus A and- B are switches of the well-known single-motion type used in telecommuniction systems, b being the rotating brush member, and a a row of bank terminals provided for each switch. It should be understood, however, that the inventionis by of about 2 volts between adjacent bank terminals.
  • ent characteristic direct current potentials are connected to the other end of the signaling circuit by the apparatus, e. g. selector,I at the identi fying end.
  • An appropriate detector provided in the signaling circuit responds only if the two potentials bear a predetermined relationship to one-another, e. g. 'if a predetermined minimum difference of a predetermined polarity exists between the potentials applied to the two ends of the signaling circuit.
  • Fig. 1 shows the .diagram of a practical embodiment in a telephone system or the like.
  • Fig. 3 shows an application of the invention to a circuit arrangement for remote control.
  • apparatus A designates a rst switch which may be any kind of electrical or mechanical appliance and which can occupy different, independent positions.
  • the drawing shows a switch having a. brush wiping over a bank of terminals, but any combination of relays, contacts on circuit breakers, etc., may be used.
  • Apparatus A is located at one end of a signaling wire or circuit and is arranged for the reception and the registering of any kind of electrical or mechanical indications, which it is desired to transmit to the distant end of the signaling circuit for identification.
  • a second switch B is like A and may be any kind of electrical or mechanical appliance, ca- ⁇ pable of exploring or hunting over a plurality of independent contacts under control of approno means limited to such apparatus.
  • Fig. 1 the source is, by way of illustration, represented in the form of a battery, of which a tapping from each consecutive cell is connected to consecutive bank terminals. thus creating a diierence of potential It should beunderstood, however, that any other source of D. C, may be used, and that any appropriate difference of potential between adjacent bank terminals may be employed.
  • the individual bank terminals of switch B are also connected to dierent direct current potentials.
  • the same source of electromotive force is used for both switches.
  • individual sources can be used for the two switches, provided that at least one common connection exists between the two individual sources.
  • the signaling system comprises also a detector arrangement D inserted in the signaling circuit.
  • the purpose of the series rectifier R isl to ensure that the detector is actuatedpnly by a potential determined relationship, e. s.. a predetermined minimum potential-difference of a predetermined sign (plus or minus) exists between the two ends of the signaling circuit.
  • switch A will, under the control of suitable means which may include the detector D, close a circuit for the operating magnet M of switch B, which will start to rotate its brushbo over its bank f terminals b, thus connecting varying direct current potentials to the other end of the signaling circuit.
  • a step-by-step rotary switch Sconstitutes the digit receiving apparatus in a register controller.
  • the rst terminal in bank g i. e. the terminal identied 4by the digit 1 received by switch S, must be connected to the same potential as terminal 3 of bank a of switch S.
  • the other terminals in bank g are connected to consecutively higher potentials.
  • the detector shown in Fig. 2 comprises a "co1dcathode tube, a transformer, several rectiers, a
  • the cold-cathode tube L is of the wen-known type which requires a speclc control gap breaktively.
  • Oneslde of this winding is permanently connected to brush y of switch SM, while the other side is connected to brush a (or brush b) of switch S via contacts of the controlling relays Ar ⁇ and Br.
  • the purpose of the rectiers associated with this winding will be explained later.
  • the secondary winding of T is connected in series with control electrode er.
  • the transformer is a step-up transformer so designed that a.
  • the register controller closes (by means indicated by switch SW not fully disclosed but as described for example in U. S. Patent No. 1,556,474 to A. Barnay) a circuit for the power magnet of switch SM, via the switch magnet and back contacts of the relays Ar, Cr and Gtr to ground.
  • the relay Ar is slow to release.
  • Switch SM starts stepping the magnet acting as its own interrupter, causing brush gto wipe over consecutive terminals in the bank. Every time that brush y encounters a terminal, a certain potential will be applied to one side of the primary of transformer T, the other side of which is connected to the potential determined by the position of switch S.
  • the potential diierence +2p causes the ionization of the control gap of the cold-cathode tube L, as previously explained.
  • This ionization causes the ionization of the main gap of the tube, resulting in the operation of relay Gtr, which is connected
  • Electrode e2 is connected to the negative side brushes a. and b of switches S and SM, respecin series with the anode A;
  • Relay Gtr opens the circuit of the power magnet of switch SM and stops the selector brush g on terminal 4.
  • relay Gtr causes the energization of relay Ar in a. circuit via the right inner back contact of Br to ground at the make contact of Gtr.
  • Relay Ar in turnopens'the anode circuit of the tube L and, since at this moment the electrical surge in the secondary Winding of T has disappeared, the tube will be extinguished, resulting in the deenergization of relay Gtr.
  • the release of the selector switch is effected in the usual manner -by operating its power magthe circuit of the magnet being closed by the deenergization of the relay Br over an off-normal contact ONC of the selector.
  • the detector Since the detector is made to respond to a given potential difference .of a given sign, it will also respond to higher potential differences of the same sign. It is, therefore, desirable to check before proceeding with further selections, whether the terminals on which the selector switch y came to rest, are the correct ones, or whether the switch, for some reason, has been overshootleading to terminal 4 in bank g is broken, switch SM would continue to rotate and would come to rest on terminal 5, where a potential difference of +31 would be applied to the detector, which wouldrespond in the usual manner. The selection should, however, y,not be allowed to proceed because it would result in a wrong connection.
  • the detector will not respond to this difference.
  • control gap breakdown voltage may be about 'I0 volts, -while the main gap breakdown voltage may be about 175 volts,
  • the rectiers R1 and Re are placed in series with the primary winding of transformer T and are so poled that the operating current of the detector is practically not iniiuenced, while the reverse current is considerably reduced ⁇ in magnitude. Due to the leakage current in all commercial rectifiers and also dueto the transient reverse current passing, ⁇ owing to the capacity n of the rectrosers, a small reverse current will, nevertheless, pass through the primary winding of transformer T. Even ⁇ this small current can be considerably reduced by the introduction of the oppositely poled rectifier Re, which is con.-
  • R3 offers very small resistance to any reverse current, in comparison with R'z, so that practically all ⁇ reverse current through the primary windingI of transformer T is eliminated.
  • a still further safeguard is provided in the rectifier R4, which is poled like Ra and provides a low resistance path for the electrical surges induced in the secondary winding of ⁇ direction of the "make" surge.
  • FIG. 3 Another application of the invention is shown in Fig. 3, where the remote control of lcircuit breakers is illustrated to the extent necessary for understanding by those skilled in the art.
  • Each circuit breaker has associated therewith a pair of signaling contacts SC arranged on rack RRI.
  • control circuit Z in rack RRZ is energized over au1 and battery Bo. This causes, by means not shown but well known in the art. switch 3 and control circuit 3 to be opened. This interrupts the energization of switch S1 and causes brush aol to be stopped on the grounded terminal 4 of bank a1.
  • Control circuit 2 also operates other control circuits and switches which are described further below.
  • the invention is not concerned with the Way in which brush aol is caused to reach a predetermined position.
  • control circuits I, 2, 3, 4 and 5 as well as switches I', Z', 3', 4 and 5 are only symbols explaining the operations to be performed.' These symbols can be replaced by any devicefor selector switch by means of grounding a terminal, hunting for the grounded terminal and stopping the selector switch when the hunting brush reaches the grounded terminal, is well known in the art ⁇ oi using selector switches and requires no further description.
  • Bank b1 of switch Si is wired to a potentiometer P1 and connects a. direct current potential to the signaling wirel 4" leading over control circuit 4 and, switch 4' (shown in/'dotted lines) to detector D which in turn is connected over wire 4"' tothe distant control station.
  • switch S1 When switch S1 has been duly set in position d of bank al control circuit Z not only deenergizes magnet circuit 3, but also, by means similar to those used for the deenergization of circuit 3 and equally well known in the art, switches 4', 3' and control circuits 4, 5 are operated.
  • -Control circuit 4 and switch 4' connect brush bo1 ⁇ and poten- ⁇ tiometer Pi to detector D.
  • Control circuit 5 and switch 5 are grounded in the front contact of relayGtr when the latter is operated by detector D.
  • an energizing circuit is closed for the power magnet of the distant control switch S2 which starts to rotate under control of a detector D like the one in Fig. 2.
  • Bank b2 of switch S2 has a brush bc2 connected to detector D, and terminals I, Z of bank I)2 connected to a potentiometer Pz, and connections are such that when the two brushes bei and lm2 are in corresponding positions then a potential difference of +23) volts will exist between brush bo of S2 and brush bol of Si which will cause the detector D to respond.
  • relay Gtr When the detectorl responds, relay Gtr operates and stops the rotation of switch Se, in exactly the same position of brush lm:i as that of brush bol.
  • the indication on a signal panel SP is given bank a2 of switch S2.
  • switches Si and S2y When the circuit breaker falls off again into outposition, switches Si and S2y will occupy the positions shown in dotted lines over terminals 4 of banks b1 and b2, respectively. In this position of S2 relay Sr at the-distant end will then be-short-circuited and unlocked causing i pendent upon the operation of the rst switch,
  • a source of directcurrent potentials each having a different predetermined magnitude a connection from said source over the first4 switch to said detector having one of said direct current potentials of predetermined magnitude, said con nection dependent upon the setting of said iirst switch, a connection from said source over the second switch to said detector having one of said direct current potentials of predetermined magnitude, said connection dependent upon the setting of the second switch, means for actuating said detector when it is subjected to two different potentials of predetermined diiference, a relay, and means for actuating said relay when said detector is actuated by a higher potential than said diilerence.
  • switch controlling means including a detector for variablyoperating the second switch dependent upon the operation of the iirst switch, a source of direct current 'potentials each having a different predetermined magnitude, a connection from said source over the iirst switch 'to said detector having one of said direct current potentials of predetermined magnitude,
  • connection dependent upon the setting of i said first switch, a connection from said source over the second switch to said detector having one of said direct current potentials of predetermined magnitude, said connection dependent upon the -setting of the second switch, means for actuating said detector when it is subjected to a potential difference exceeding a predetermined minimum, a relay for indicating incorrect setting of said second switch, and means for actuating said relay when said detector issubjected to a, potential diierence which exceeds said minimum potential difference by ya predetermined amount.
  • a first switch having two backs of terminals and a brush cooperating With each bank, a second switch hav- N ing a bank of terminals and a brush cooperating therewith, a magnet for moving the brush of the second switch over its terminals, a signaling circuit extending fromthe brush of th'e second switch and normally connected to a first brush of the rst switch, a detector in said circuit, a source of direct current potential, means for applying to said detector direct current potentials of predetermined magnitudes depending on the position of the brush of the second switch, means for applying to said detector over said first brush of said first switch direct current potentials of predetermined magnitudes depending on the position of said first switch, means for actuating said detector when the difference between the two potentials applied thereto exceeds a predetermined minimum, a first relay, a second relay for Ipotentials of different predetermined magnitudes dependent upon the position of the rst switch, i
  • a variably operable first switch a second switch, switch actuating means including a detector for variably operating the second switch dependent upon the operation of the first switch, a source of different direct current potentials each having a predetermined magnitude, a first set of electrical contacts in said first switch and a second set of electrical contacts in said second switch, connections from said source to the respective contacts of the said rst and second sets of contacts, each connection having .one of said diierent direct current potentials, a flrst connection froma nection a single direct current potential of one predetermined magnitude.
  • each switch hav- -ing a set of contacts and a brush movable over its associatedset-oi contacts, a magnet for controlling the movement of the brush ofthe second switch over its -associated setV of contacts, a detector for controlling said magnet, a Isource of different direct current potentials each having a predeterminedmagnitude, connections from said source to the respective contacts of each set of contacts and means for maintaining along each connection one of said dverent direct current potentials, a rst connection from the brush of the contact engaged by the brush of the iirst switch, a second connection to said detector and means for maintaining along said second connection a single direct current potential of one predetermined magnltude, said second connection dependent uponthe position of the brush of the second switch, and means for actuating said detector ⁇ when the vtwo single potentials applied thereto bear a predetermined relationship to one another.
  • first and second switches each switch having a'set of contacts and a brush movable over its associated set of contacts, a magnet for controlling the movement of the brush of the second switch over its associated set of contacts, a detector comprising a transformer having a primary and a secondary winding and an electron discharge tube having a pair of electrodes forming a control gap and a pair of electrodes forming a main gap, a relay for controlling the operating of said magnet in series with said main gap, connections from the ends of said secondary winding Vto the electrodes forming said control gap, means for simultaneously applying diierent direct current potentials to the respective contacts of each set of contacts, means for applying to one end of said primary winding over the brush of the rst switch a selected direct current potential of a predetermined magnitude depending upon the contact engaged by the brush of the rst switch, means for applying to the other end of said primary winding direct current'potentials of predetermined magnitudes dependent upon the position of the brush of the second switch, and means
  • a plurality of conductors means for maintaining along each conductor a predetermined direct current potential, a potential responsive device, means for applying to said device a desired one of predetermined direct current potentials, means controlled by said device for connecting said conductors to said device, and means for operating the device when the potentials applied thereto are different and have a predetermined difference.
  • a plurality of conductors means for maintainingalong each conductor a predetermined direct current for applying, and means for operating the multil2 electrode tube when the potentials applied thereto have a predetermined diilerence.
  • switches each having a bank of terminal sets in which said lines terminate and a set of wipers arranged to wipe over said terminals, a magnet for controlling the movement of the wipers of each-switch, sources of predetermined direct current potentials, connections for placing potentials on lines, one predetermined potential on each line dependent upon its designation, a multielectrode electric discharge device, means for applying to the electrodes of the device potentials eidsting on the terminals of different switches, means for operating said device only when the potentials applied from the switches bear a predetermined relationship to one another, and means actuated upon the operation of the device for controlling one of said magnets to stop the associated wiper.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Keying Circuit Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Selective Calling Equipment (AREA)
US472614A 1941-04-15 1943-01-16 Electrical signaling system Expired - Lifetime US2444065A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL101040A NL57800C (nl) 1941-04-15 1941-04-15 Electrisch seinstelsel

Publications (1)

Publication Number Publication Date
US2444065A true US2444065A (en) 1948-06-29

Family

ID=93258029

Family Applications (1)

Application Number Title Priority Date Filing Date
US472614A Expired - Lifetime US2444065A (en) 1941-04-15 1943-01-16 Electrical signaling system

Country Status (9)

Country Link
US (1) US2444065A (da)
AT (1) AT167785B (da)
BE (1) BE445114A (da)
CH (1) CH228351A (da)
DE (1) DE861268C (da)
DK (1) DK64480C (da)
FR (1) FR881538A (da)
GB (1) GB617100A (da)
NL (1) NL57800C (da)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2579333A (en) * 1948-04-20 1951-12-18 Cie Ind Des Telephones Rotary-switch stopping circuit
US2583014A (en) * 1942-06-12 1952-01-22 Int Standard Electric Corp Automatic control of final selectors
US2584153A (en) * 1945-09-14 1952-02-05 Roelof M M Oberman Zero voltage identification device for selector positioning
US2591555A (en) * 1949-05-25 1952-04-01 Ncr Co Indicator
US2597007A (en) * 1942-03-31 1952-05-20 Int Standard Electric Corp Common control circuit for operating switches rearward to calling line
US2620385A (en) * 1949-11-30 1952-12-02 Specialties Dev Corp Photoelectrically controlled system for detecting suspended matter in fluids
US2648057A (en) * 1946-07-16 1953-08-04 Roelof M M Oberman Circuit for obtaining electric bridge equilibrium
US2652454A (en) * 1949-11-26 1953-09-15 Automatic Elect Lab Rotary connector switch
US2654000A (en) * 1948-05-20 1953-09-29 Int Standard Electric Corp Multipotential type register controller
US2663760A (en) * 1948-10-12 1953-12-22 Hartford Nat Bank & Trust Co Control device for use in automatic signaling systems
US2688659A (en) * 1949-10-31 1954-09-07 Hartford Nat Bank & Trust Co Circuit-arrangement for use in automatic signaling systems for numerical adjustment of a switch by a selective marking method
US2693504A (en) * 1949-06-14 1954-11-02 Hartford Nat Bank & Trust Co Automatic signaling system
US2697751A (en) * 1949-06-14 1954-12-21 Hartford Nat Bank & Trust Co Circuit-arrangement for use in automatic signaling systems for selectively testing the values of identification resistances
US2744164A (en) * 1951-12-13 1956-05-01 Siemens Ag Device for controlling selector switches in automatic telephone systems
US2821573A (en) * 1953-07-24 1958-01-28 Itt Dual-switch finder combination
US2832834A (en) * 1941-04-26 1958-04-29 Nederlanden Staat Signalling arrangement for telecommunication systems
US2869110A (en) * 1954-08-09 1959-01-13 Ingersoll Milling Machine Co Remote control apparatus
US2885480A (en) * 1942-10-31 1959-05-05 Staat Der Nederlanden Ten Dze Relay register
US2923919A (en) * 1960-02-02 Remote control circuit
US3056126A (en) * 1957-04-08 1962-09-25 Gen Railway Signal Co Indicator control system for a train describer

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1212554A (en) * 1913-08-19 1917-01-16 Charles Prache Electrical control mechanism.
GB266798A (en) * 1925-11-26 1927-02-28 Ian Miller Edington Aitken Improvements in or relating to electric signalling systems
US1669112A (en) * 1924-09-15 1928-05-08 Gen Electric Supervisory control system
US1736259A (en) * 1927-07-14 1929-11-19 A copabtnership consisting of charles a
US1952368A (en) * 1927-08-06 1934-03-27 John E Gardner Selecting system
US1982290A (en) * 1927-12-24 1934-11-27 John E Gardner Selecting system
US2032514A (en) * 1935-06-01 1936-03-03 American Telephone & Telegraph Gas-filled tube and circuit therefor
US2060184A (en) * 1935-11-21 1936-11-10 Bell Telephone Labor Inc Telephone system
US2279232A (en) * 1939-01-23 1942-04-07 Louis Letterman Selective control apparatus
US2323019A (en) * 1936-09-26 1943-06-29 Dohle Hinrich Impulse sender
US2333195A (en) * 1939-04-04 1943-11-02 Int Standard Electric Corp Key pulsing sender for telephone systems

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1212554A (en) * 1913-08-19 1917-01-16 Charles Prache Electrical control mechanism.
US1669112A (en) * 1924-09-15 1928-05-08 Gen Electric Supervisory control system
GB266798A (en) * 1925-11-26 1927-02-28 Ian Miller Edington Aitken Improvements in or relating to electric signalling systems
US1736259A (en) * 1927-07-14 1929-11-19 A copabtnership consisting of charles a
US1952368A (en) * 1927-08-06 1934-03-27 John E Gardner Selecting system
US1982290A (en) * 1927-12-24 1934-11-27 John E Gardner Selecting system
US2032514A (en) * 1935-06-01 1936-03-03 American Telephone & Telegraph Gas-filled tube and circuit therefor
US2060184A (en) * 1935-11-21 1936-11-10 Bell Telephone Labor Inc Telephone system
US2323019A (en) * 1936-09-26 1943-06-29 Dohle Hinrich Impulse sender
US2279232A (en) * 1939-01-23 1942-04-07 Louis Letterman Selective control apparatus
US2333195A (en) * 1939-04-04 1943-11-02 Int Standard Electric Corp Key pulsing sender for telephone systems

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2923919A (en) * 1960-02-02 Remote control circuit
US2832834A (en) * 1941-04-26 1958-04-29 Nederlanden Staat Signalling arrangement for telecommunication systems
US2597007A (en) * 1942-03-31 1952-05-20 Int Standard Electric Corp Common control circuit for operating switches rearward to calling line
US2583014A (en) * 1942-06-12 1952-01-22 Int Standard Electric Corp Automatic control of final selectors
US2885480A (en) * 1942-10-31 1959-05-05 Staat Der Nederlanden Ten Dze Relay register
US2584153A (en) * 1945-09-14 1952-02-05 Roelof M M Oberman Zero voltage identification device for selector positioning
US2648057A (en) * 1946-07-16 1953-08-04 Roelof M M Oberman Circuit for obtaining electric bridge equilibrium
US2579333A (en) * 1948-04-20 1951-12-18 Cie Ind Des Telephones Rotary-switch stopping circuit
US2654000A (en) * 1948-05-20 1953-09-29 Int Standard Electric Corp Multipotential type register controller
US2663760A (en) * 1948-10-12 1953-12-22 Hartford Nat Bank & Trust Co Control device for use in automatic signaling systems
US2591555A (en) * 1949-05-25 1952-04-01 Ncr Co Indicator
US2693504A (en) * 1949-06-14 1954-11-02 Hartford Nat Bank & Trust Co Automatic signaling system
US2697751A (en) * 1949-06-14 1954-12-21 Hartford Nat Bank & Trust Co Circuit-arrangement for use in automatic signaling systems for selectively testing the values of identification resistances
US2688659A (en) * 1949-10-31 1954-09-07 Hartford Nat Bank & Trust Co Circuit-arrangement for use in automatic signaling systems for numerical adjustment of a switch by a selective marking method
US2652454A (en) * 1949-11-26 1953-09-15 Automatic Elect Lab Rotary connector switch
US2620385A (en) * 1949-11-30 1952-12-02 Specialties Dev Corp Photoelectrically controlled system for detecting suspended matter in fluids
US2744164A (en) * 1951-12-13 1956-05-01 Siemens Ag Device for controlling selector switches in automatic telephone systems
US2821573A (en) * 1953-07-24 1958-01-28 Itt Dual-switch finder combination
US2869110A (en) * 1954-08-09 1959-01-13 Ingersoll Milling Machine Co Remote control apparatus
US3056126A (en) * 1957-04-08 1962-09-25 Gen Railway Signal Co Indicator control system for a train describer

Also Published As

Publication number Publication date
NL57800C (nl) 1946-07-15
FR881538A (fr) 1943-04-28
AT167785B (de) 1951-02-26
CH228351A (de) 1943-08-15
GB617100A (en) 1949-02-01
DE861268C (de) 1952-12-29
DK64480C (da) 1946-05-13
BE445114A (fr) 1942-05-30

Similar Documents

Publication Publication Date Title
US2444065A (en) Electrical signaling system
US2424585A (en) Telecommunication system
US2303016A (en) Impulse counting circuit
US1498544A (en) Electrical selective system
USRE22794E (en) G deakin
US2242776A (en) Telephone system
US2208655A (en) Condenser storage equipment
US2291481A (en) Telephone system
US2547043A (en) Automatic control of selectors by register potential matching
US2237413A (en) Telephone system
US1945665A (en) Supervisory control system
US2319333A (en) Service observing system
US2245160A (en) Telephone system
USRE22861E (en) Electric selection controlling
US2354667A (en) Electric selection controlling circuit
US3423539A (en) Automatic telephone exchange switching systems
US2338218A (en) Time-measuring device
US2468429A (en) Selective message register system
US1450321A (en) Party-line revertive ringing system
US2045450A (en) Signaling system
GB683911A (en) Improvements in station identification circuits for telephone systems
US2471415A (en) Telephone calling line identification system
US2306087A (en) Key pulsing register circuit
US2322650A (en) Impulsing apparatus for signaling systems
US2773127A (en) Calling line identification apparatus