US2224677A - Signaling system - Google Patents

Description

HANSCOM SIGNALING SYSTEM Filed March 23, 1,939

Avon/v5 Patented Dec. 10, 1940 I UNITED STATES STGNALING SYSTEM `Clarence D. Hanscom, Denville, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application March 23, 1939, Serial N0. 263,585

Claims.

This invention relates to telephone systems and particularly to improvements in automatic telephone systems.

An object of the invention is to simplify anc.

5 improve automatic telephone systems of the character in which connections are established over a path including the beam of an electronic device.

Heretofore systems have been provided in l0 which a connection from one subscribers line to any one of a plurality of other subscribers lines has been established by deilecting the beam in a cathode ray tube to corresponding contacts at the end of the tube and using the beam as part of the talking path. I

The present invention has been applied to an arrangement of this kind in which a cathode ray tube is employed as the selector for establishing telephone connections by the deection of an electronic beam by dial pulses; and a feature thereof is thev arrangement whereby the beam is maintained locked in a deected position by a circuit over the beam and whereby the dial pulses causing the deection are extinguished as soon as the deflection is accomplished.

The invention has been illustrated in the accompanying drawing which shows a calling subscribers line and a cathode ray tube used as the selector employed in accordance with the principles of this invention.

Referring now to the drawing a subscribers substation has been shown at l with the line terminating in the cathode ray tube 2 which is provided with the usual filament 3 connected to a suitable source of current for the production of an electron beam through the tube. This beam is employed as the selecting means and as a path for talking current as will hereinafter` be described. The cathode element i is connected to the subscribers line, and an anode 5 is provided to control and concentrate the beam of electrons as is Well known in the art. The battery 24 is provided to impress a positive potential on anode 5 with respect to cathode A pair of deflection plates 6 and 'l are provided in the tube in any well-known manner to deflect the beam onto the anode terminals shown located at the end of the tube and collectively marked with the numeral 8. To these terminals are connected individual conductors. The rst conductor 9 represents one conductor of the :first subscribers line and the remaining conductors lead to other equipments of this kind for other subscribers lines and are equally spaced with respect to each other, except the distance between the conductor 9 and the second conductor I0. This distance represents, if the subscriber at l is considered as the rst subscriber in a group of ten, two spaces so that when the beam is deiiected to select the second subscriber it must be deflected two steps. The 5 rst step will point the beam onto a terminal ll which is provided for holding the beam between pulses as will hereinafter be described. The corresponding terminals for the second subscriber terminate in the group designated with the refl0 erence character l2 and the corresponding terminals for a third subscribergterminate in the group designated with the number I3. Another conductor I4 is common to all groups of conductors leading to all of the subscribers equipi5 ments.

The individual subscribers conductors as for example, the group 8 terminating at the first subscribers equipment are connected to individual filters marked as'a group with the numeral l5 20 and provided to prevent voice currents from passing through the resistances I6 to the conductor Il which is employed as will hereinafter be described in connection with the operations of the circuits.

Two discharge tubes i8 and i9 are connected through various circuits including sources of potentials and an induction coil 2li, one winding of which is connected to a dial 2| for the sending of the impulses to deilect the beam to the proper 30 terminal in the tube 2. The tube l@ may be of the gas-filled type, so that the anode discharge current continues to flow following the removal of the input signal.

A detailed description will now be made of the 35 operationof this system in the selecting and establishing of a connection from the subscriber at l to one of the other nine of the group of ten subscribers. It should be noted that normally the electrons emitted from the cathode l provide a 4@ cathode ray beam 22 which is controlled by the anode 5 and normally maintained deflected by the potential diierence between plates 6 and 'l to strike the terminal 23 so that calls incoming to subscriber I may pass over this beam as will here- 45 inafter be described. With this in mind. if the subscriber at l removes his receiver from its switchhook, he closes the circuit between the element d and the anode 5 through the battery 2t to control the beam to establish a talking con- 5o nection as will be described. If the subscriber then operates his dial 2l by closing a connection between the pulse contacts, it will be noted that on therst impulse the potential on the grid 25 of the tube I8 will be changed to become less 55 ment 33, plate 34, resistance 35, back to battery 32. It will be observed that it is the connection through the potentiometer 39, the battery 31, and

resistance 35 that normally maintains a potential difference between the plates 9 and 1 to maintain the beam 22' on terminal 23. On the other hand on the establishing of the circuit through the output circuit of tube I8, the potential between plates 6 and 1 is changed so that the potential on plate 6 becomes less positive in relation to the potential-on plate 1. This change is sufficient to deflect the beam from the terminal 23 one step downwardly to strike the terminal I I. No selective connection will be established across the beam at" this time as it takes two impulses to establish a connection to terrnlnal 39 for establishlng a connection to the second subscriber in the group of ten.

It should be explained at this point how the beam is maintained on a terminal after having been once set. The operations in this respect are as follows: A current through the output circuit of tube I9 also ows through the primary winding 40 of theinduction coil 4I. This causes a momentary impulse of current to ow through the secondary winding 42 of this induction coil 4I which has the eect of making the grid 43 less negative in relation to the potential of filament 44 as normally established by the battery 45 and potentiometer t6 in parallel and the connection through the secondary winding 42 of the induction coil 4I between the filament 44 and the grid 43. This momentary change of potential between these elements causes a current to flow through the output circuit of the tube for maintaining the potential difference now established between the plates 6 and 1 as follows: From filament 44,

battery 50, conductor I1, resistances I6. second terminal Il, beam 22, element 4, contacts on the switchhook of subscriber I, primary winding 52 of induction coil 20, resistance 35, battery 54, plate 55, back to filament 44. As the plates 6 and 1 are connected to opposite sides of resistance 35, the potential difference established between these plates will now be maintained iby this circuit through resistances I6 so that the beam will be held on the terminal Il. this circuit also establishes through the circuit including Winding 21 of the inductance coil 20, a mementary impulse which is in opposition to the current passed through this circuit by the clos-- ing of the contacts at dial 2i and therefore extinguishes the pulse established by their contacts at 2I through the output circuit of tube I8. Thus the impulse that causes the beam to stop is quenched immediately to obviate the possibility of moving the beam a second step accidentally.

'The circuits now remain in this condition so' that beam 22 is held on terminal II until the next impulse comes along.

When this takes place,`that is, when the contacts of dial 2| are again closed, the potential difference between the plates 6 and 1 is again changed, and thus causes the beam to be deilected to strike terminal 39 whereupon the abovementioned circuit through the tube I9 and re;- sistances I6 is closed with the exception that a portion of this resistance is eliminated so that the beam will now be maintained on this terminal until the next impulse comes along. The

The current through 2,224,677 negative due to the connection of the battery 26 second impulse is extinguished by the momentary impulse through the winding 21. These operations are then repeated if additional impulses are sent and the potential on plate 8 is made less and less positive as the' resistance through the circuit for maintaining the potentials decreases as additional units of the group I6 are eliminated. i

The line potential filters shown at I5 are as stated for the purpose of preventing talking current from disturbing the holding circuits. There is one of these filters inserted in each line between the resistances I6 and the terminals associated therewith.

If it is assumed that only two impulses are sent, the beam will remain' on terminal 39 and a connection will therefore be established over the common conductor I4, the subscribers telephone set I, control element 4, beam 22, terminal 39 and the conductor I0, thus causing the selection of the second subscriber. This circuit is continued over the conductor I0 through talking battery 51. The conductor vI9 terminates in the second subscribers cathode ray tube at the rst terminal corresponding to` terminal 23 in tube 2. From there it is extended through the beam corresponding to beam 22, the element corresponding to element 4, through the called subscribers ringer back over the common conductor I4. This causes the called subscribers ringer to operate and when the called subscriber answers, the ringer is eliminated and a connection is completed for talking between the first and second subscribers. If the second subscriber had called the first subscriber, he would have dialed one impulse and established a connection through his tube, over conductor 9, through talking battery 60, beam 22, element 4, subscribers ringer at station I, common conductor I4, back to the second sub-l scribers equipment, over the elements and beam of the tube corresponding to tube 2 to conductor 9. In a similar manner connections may be established from any subscriber to any` other in the system disclosed in this drawing which comprises as stated a group of ten subscribers lines.

What is claimed is:

1. In a signaling system, a cathode ray tube, a 'plurality of anodes in said tube, means for deflecting the cathode ray in said tube from one anode to another, and means operative over said ray for maintaining the ray deflected on an anode after having been deflected by said rst means to said anode and until said first means again deflects the ray to a succeeding anode'.

2. In a signaling system, a cathode ray tube, signaling circuits, a plurality of anodes in said tube, means for transmitting momentarily succeeding impulses, means for deilecting the cathode ray in response to succeeding impulses from one anodelto another to select said signaling circuits, and means for maintaining the ray deected on an anode between impulses.

3. In a signaling system, a cathode ray tube, a plurality of anodes in said tube, an impulse transmitter, means for deilecting the cathode ray in said tube from one anode to another in response to succeeding impulses from said transmitter, and means for maintaining the deflected ray in the deflected position on an anode after the impulse having deflected it`to said anode ceases and until the ray is again deected by ansaid tube from one anode to another in response to succeeding impulses from said transmitter, means for operating said deecting means to maintain said ray deflected between impulses and forextinguishing said impulses as soon as they have deflected the ray.

5. In a signaling system, a cathode ray tube, a plurality of anodes in said tube, an impulse transmitter, means for deilecting the cathode ray in said tube from one anode to another in response to succeeding impulses from said transmitter, and circuit means including the ray for operating said deecting means to maintain said ray deiiected and for extinguishing said impulses as soon as they have deected theray.

6. In a signaling system, a cathode ray tube, a plurality of anodes in saidtube,-. means for deiiecting the cathode ray in said tube from one anode to another, a circuit closed over said ray when deected to an anode for-maintaining said ray deected on said anode until again deected to another anode, and -a communication circuit established over said cathode ray.

7. 'I'he combination in signaling system of an electron discharge tube having a plurality of electrodes and means for producing an electron discharge, a plurality of telephone lines connected respectively .to said electrodes, means for progressively deecting the electron discharge from one electrode to the next to select a desired one of said telephone lines, circuit means including the electron discharge for maintaining said discharge on each successive electrode to which it is deflected, and circuitmeans including said electron discharge -for establishing a talking connection with the selectedone of said telephone lines. 8. In a signaling system, a cathode ray tube. a plurality of anodes in said tube, animpulse transmitter, means for deecting the cathode ray in said tube from one anode toanother in re-l sponse to succeeding impulses from said transmitter, a discharge tube, means for actuating said discharge tube in response to succeeding impulses from said transmitter, and means responsive to the actuation of said discharge tube and includingsaid cathode ray for extinguishing said impulses as soon as they have deected the ray and for operating said deecting means to maintain said ray deilected on the anode to which it has been deiiected by a preceding impulse until a succeeding impulse is received.

9. In a cathode ray tube, deflection plates in said tube, a plurality of anodes in said tube, an impulse transmitter, a discharge tube, a circuit between said impulse transmitter and said discharge tube for the actuation of the discharge tube in response to impulses from said transmitter, an output circuit'from said discharge tube to said deection plates for, deecting the cathode ray from one anode to another in succession in response to impulses from said transmitter, a second discharge tube, an input circuit for said second discharge tube associated with the output circuit of said ilrst discharge tube for actuating said second dischargetube each time said output circuit is actuated, an output circuit for said second discharge tube including the cathode ray for maintaining tre deection of the ray as deflected by a preceding impulse and for quenching said preceding impulse as soon as said output circuit of said second discharge tube becomes effective until a succeeding impulse is received to deflect the ray to a succeeding anode.

10. In a signaling system, a cathode ray tube having ldeflection plates, a calling signaling circuit associated with said tube, a plurality of anodes in said tube, a signaling circuit associated with each anode, an impulse transmitter,

means including a' discharge tube and the deflection plates operative in response to succeeding impulses from said transmitter .to deiiect the cathode ray from one anode to another to select a signaling circuit and connect it to the calling signaling circuit over said ray, a second discharge tube associated with said rst discharge tube and

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