BE465858A - - Google Patents

Description

       

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  The company known as: Automatic Electric Laboratories Inc in Chicago 7, State of Illinois (United States of America) Improvements in switching systems for telephone and other equipment.



  International Convention: United States Patent Application No. 591,703 filed May 3, 1945 by Clarence Marble, of which the applicant is the beneficiary.



   The present invention relates to improvements to automatic switching systems for telephone and other communication equipment in which a dial of the type commonly used in telephony is employed to actuate receiving equipment of a telephone system. the selection, connection-and control of its different elements, units or lines.



   Objects of the invention are: Firstly to provide an automatic switching system employing a lower number of operating elements, occupying less space, requiring less wire and less labor. maintenance and costing less than any automatic switching system with an equal number of elements to be connected together and with the same operating characteristics; second to provide for all the operating characteristics currently in use in the operation of automatic switching systems, such as the sound of the dial operation, the sound

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 reversion bell, the busy sound, a central source of motive power and an automatic bell;

   thirdly to provide selector equipment in which the operations of maneuvering from the dial to the calling telephone set or the like impulses established by other means produce in an appliance room a circuit network so arranged that only a desired element, a desired unit or a desired line in the system responds; fourthly, in a piece of equipment individually to each element, unit or line of the system, functions making this piece of equipment capable of responding as a calling device or as a called device depending on its situation in a connection ; fifthly, to provide equipment to which the calling and called organs are attached for the duration of a communication and without interference with other communications;

   sixthly, to provide equipment which accompanies the called device to its point of connection with the called device and controls the establishment of the communication; seventh to provide equipment for adjusting the time of communications and for preventing interference when two or more communications are being prepared at the same time; eighth to provide for the recording of delayed communication; ninth place to provide an audible signal which announces the possibility for the apparatus to complete a communication; in the tenth place to provide the visual indication of a part of the equipment which cannot complete a communication;

   in the eleventh place to provide characteristics which prevent the simultaneous connection of two or more calling elements, units or calling lines at the same instant and the clashes which are the consequence thereof; twelfth to provide characteristics which allow two or more elements, units or lines

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 to use the same telephone number and answer accordingly as needed for private branch office telephone trunk lines; thirteenth place, if used for connecting two telephones, to provide a talking circuit which is kept free from all operating equipment except the windings of the usual battery supply coils;

   in the fourth place to provide a quality of telephone line in this system adaptable to the various auxiliary circuits and normal equipment for a large-scale telephone central office; Fifteenth place to provide facilities for selective ringing in lines of participants.



   Hitherto automatic switching systems have been used for the communication of telephone lines by which a subscriber desiring a certain line could be connected by a series of operations by means of limited channels established by relays or switches in accordance with each operation of the dial. It is, for example, common practice in large telephone offices using currently available switching systems to direct incoming calls, through successive channels to desired groups of miles and then hundreds to the associated final unit. to a desired line.

   With these systems, if the prescribed maximum load for the established channel has been reached, subsequent calls directed into a channel when its maximum load has been reached are not processed and the call is lost or delayed. In any telephone system, a group of lines (eg 100) may have a high percentage of its lines in service, eg 25%, and yet the system as a whole may at the same time and under load maxima have only 3 to 5%

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 of its lines in service.

   The present invention terminates the lines in a system in the same situation as part of a group consisting of a total number of lines in the system and therefore the switchgear should be planned only to meet the 3 to 5% simultaneous communications or has any percentage of average communication talk time and call speeds that a given telephone system as a whole guarantees.

   In addition, telephone systems have heretofore established a conversation channel from the calling line through a series of miscellaneous equipment or relay combinations to the called line, which necessitates the installation of a. equipment large enough to provide conversational facilities as well as selection and control facilities throughout the system.



  With the present invention, the called line is reached by a selector employing only signal wires.



  Thus, earlier systems consisting of ten thousand terminations required a minimum of thirty thousand wires between switches and other devices used to select called lines and called line equipment. With the present invention only two hundred threads are needed for the same purpose for a ten thousand line system. Further, with the present invention regardless of the size of the system, no train consisting of a number of selectors and connectors or large groups of relays is required to establish communication between the calling and called telephones of the system. system.

   When the calling line is activated it engages a selector which in turn becomes active and connects the called line to the calling line in accordance with the control operations of the calling lines.



   The present invention includes controls for preventing two or more incoming calls from arriving at the telephone.

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 same instant and simultaneously connect to the same selector equipment, but apart from this protection feature, each call is established independently and is not affected by the call operations of any other line. On completion of the dial maneuver, a call may be slightly delayed while waiting for the connection or the busy report, but this delay will not be due to the action of another line establishing its connection. .



   The invention will be better understood on reading the following description, taken together with the appended drawings in which:
Fig. 1 is a block diagram showing the relative arrangements of a small number of the main elements of the present invention, eight typical dial telephones with their line equipment, their relationship to the multiple aspects of three selector circuits and their relationship to the multiple aspects of three selector circuits. equipment, exploration equipment, multiple selection and different operating arms.



   In fig. 2 is an elevational view showing the arrangement of selector circuit contact tabs multiplyed on a line. This figure shows a side of vLngt selector circuits as they would appear in a three-line equipment.



   Fig. 3 is a plan view of one side of the selector contact legs as they would appear for three lines. It shows the arrangement of the contact legs of the assembly bolts, the terminal legs for the connection of the wire and the arrangement of support members.



   Fig. 4 is an end view of the selector contact multiple and shows the two groups of selector air-baked contacts and their holders. The guides for the line operating equipment are shown and the dotted lines represent the position of the line equipment in relation to the selector contacts.

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   Figure 5 is a line circuit diagram and shows the electrical details employed by any line in call and answer operations. Mechanical details essential for the description of circuit details are also shown. Also shown for ease of description is a dial telephone and ring generator equipment. Recording and warning circuits are shown with the control mechanism which puts them into action.



   Fig. 6 shows the appearance of two selector circuits and their contact pacts with line equipment.



   Fig. 7 is a schematic of circuit details added to the line circuits to control the order of succession in which lines call at the same time. t are accepted.



   Figure 8 is a schematic of circuit details to be added to line circuits when two or more lines use the same calling number as in private branch office trunk lines.



   Fig. 9 is an elevational view showing the essential mechanical details of a typical line unit.



  Dashed lines indicate its relationship to the selector contact multiple and the supporting frame.



   Fig. 10 is a plan view of a line unit in section immediately below the upper crosspiece 985 and shows the relative arrangement of the various pieces of equipment making up the unit.



   Fig. 11 is a perspective view of one side of the line unit control arm and is intended to more clearly show the control and locking functions of the unit.



   Fig. 12 is a perspective view showing the relative arrangement of the contact fingers on one side of the bias

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 actuation of the line unit.



   Fig. 13 is a perspective view showing the mechanism employed to actuate a control arm for propulsion by a continuously rotating eccentric wheel.



   Fig. 14 is a schematic view showing the arrangement of the actuation mechanism employed to return line units to their limit of operation. has been reached.



   Fig. 15 is a schematic diagram of the selector circuits and includes the representation of sufficient mechanical details to make the description clear.



   Fig. 16 is a combined end view and partial section of the line model selector switch.



   Fig. 17 is a plan view, in section, showing part of the operating mechanism of the line model selector switch.



   Fig. 18 is a partial plan view showing the relative arrangement of the contacts in the line model selector switch.



   Fig. 19 is a partial end view and sectional view of the rows of fixed "hundred" and "tens" contacts and shows their relation to the operating mechanism.



   Fig. 20 is a plan view of a stamped part which provides the common contact springs for each horizontal row of selector pattern contacts.



   Fig. 21 indicates the wiring required between switches and line equipment in a ten thousand line system using the principle shown in fig. 22.



   Fig. 22 is a functional diagram showing the essential details of the principle employed for establishing models for the selection of the various lines

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 in an eighty-one line system.



   Fig. 23 is a diagram of the line equipment unit disconnect control details.



   General description of the invention.



   Any subscriber of a telephone system incorporating the present invention, by lifting the handset or the receiver of his rotary telephone, activates the associated and clean line equipment. his line. This equipment mainly consists of five relays and an operating mechanism. Two of the five relays operate when the line is calling and four of the five relays operate when the line is called (answering).



  The operating mechanism is in action when the line is calling or responding. The operating mechanism consists mainly of a frame to which is attached an arm carrying six finger-shaped friction contacts. Its movement is caused by a ratchet movement shaft which is put into action by the operation of certain relays and the engagement with an eccentric or a continuously rotating cam specific to each line equipment. Line equipment includes a restraint mechanism consisting of a spindle device which engages a slot in the movable arm when operating a restraint relay when needed.

   Each line equipment also includes three capacitors for controlling the battery supply and reverting ring tone, terminals not shown in the drawing for the connection of the outside line extending to the telephone of the line. subscriber and for connection of the ringing current and of the positive and negative battery, an actuating mechanism for reversing the direction of movement of the operating arm when employed for the calllet to sound a warning like c 'is necessary when put into action for the response. The six contacts in the form of fingers or wipers

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 try three circuits.

   Two of the contacts carry the talk and pulse circuit; two are used for a circuit which chooses and keeps selector equipment free and the other is used for carrying a circuit connecting and holding the called line to the selector circuit when the called line is in action.



   As the line equipment operating arm advances, its contact fingers encounter various fixed contacts or tabs arranged in groups of six.



  Three of these fixed contacts are in a row on each side of the operating arm. Each of these groups of six fixed contacts or tabs comprises a multiple aspect of three two-conductor circuits which extend to a selector. Each selector is represented, at each line item of the system, by a mul- tiple aspect of the three circuits on legs accessible for engagement with the operating arm of each line.



  One of the three circuits indicates free or busy selector equipment, and, if seized with the operating arm of a calling line, if a certain selector circuit is free, this circuit causes the arm to be locked in place. line equipment operation on the calling line. This circuit also changes situa-! When connecting a calling line to the selector equipment, and indicates to calling lines subsequently paging that the selector circuit is busy. A relay in the selector circuit is involved in establishing this occupied state and maintaining the connection of the two circuits. Another of the three circuits is the talk path which ends in the selector on battery and earth by means of a battery supply relay.

   When the conversation path is closed to the calling telephone, the line equipment is so arranged that the conversation circuit is kept open when it crosses circuits.

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 selector switch occupied to prevent knocking in this circuit. Although the calling line, while searching for a free selector circuit, has the battery applied to the same potential as that on the selector battery supply relay, differences in resistance of the coils and circuits could. cause knocking as a result which the above-mentioned device avoids.

   When connecting a calling line and a free selector, the calling line's battery supply relay is disconnected from the communication and the calling station then receives its battery supply from the selector. Engagement of a calling line and a free selector operated the calling line restraint mechanism and opened the circuit engaging the line operating mechanism as a result of the operation of a relay in the line. the line circuit, which is locked when it finds a free selector and remains locked while a communication is established. This latched relay also disconnects the battery supply relay from the line circuit, the calling line then receiving its battery supply from the selector to which it is attached.

   The third circuit in the selector is used to connect the answering line to the calling line when the answering line has been found and activated by the selector.



   During a period of peak load, a calling line searching for a free selector may not find the desired circuit on its first movement through the selector circuits. The line switchgear is arranged in such a way that if a line unit completes a scan run through the selector circuit and does not find a free selector, it operates a trigger mechanism which causes the operating arm returns to normal and starts the search for a free selector again. This process

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      will continue until a free selector is found or the calling participant disconnects.

   As the line operating arms will find it only necessary to make two or more runs across the multiple of the selector during periods when all of the selector circuits are occupied at the same time, which will only occur when the load of traffic exceeded its normal expected peak, a logger was added to the system to indicate that an overload has occurred and its extent.



   The calling line is now connected to the selector equipment and the battery supply to the calling line is established via a relay in the selector. This relay operated when communication was established between the calling line and the selector.



  The operation of this battery supply relay caused the operation of the associated relays. One of these associated relays, being of a type designed for slow release, is not affected by the impulses of the dial, therefore remains actuated throughout the connection period and thus maintains the others in the actuated state. . This second relay is used for many selector functions. When the selector was free, one of its rear contacts presented earth to the calling lines in search. When the selector is picked up by a calling line, it supplies the battery to the relay controlling the locking mechanism of the calling line.

   This relay also controls in the selector the setting of the dial operation sound and, if necessary, the busy sound on the calling line at the same time as it connects the equipment which is connected. will choose the answer line when the dial maneuver occurs. It also releases the selection equipment when the call is completed.



   When the selection equipment is taken up by a calling line, the dial operation sound is connected and indicates to the calling subscriber that the ma-

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 the work of the dial can begin. The calling subscriber activates his dial interrupting the current flowing in the line at a desired value according to the number of the desired telephone as it is commanded by the dial and causing the production of a series of breaks and closures. in the battery supply circuit, causing the battery supply relay to oscillate accordingly. The selector circuit is disppsed in such a way that each series of pulses causes the operation of certain fixed contacts or of recorders in accordance with the values formed on the dial.

   In an office with 10,000 terminations, four operations of the dial would be necessary. On completion of these four dial operations, the selector equipment is arranged in such a way that it is ready to activate the line which is called. At the same time as the maneuver of the dial in the calling line is completed, an exploration apparatus is put into action.



  The scanning device is provided to control the connection of called lines and to prevent the simultaneous connection of two answering lines. This apparatus consists of an operating arm, similar to that of the line equipment except that it carries only two contact fingers or wipers instead of six. The movement of the exploration arm is controlled by an electromagnet which forces its shaft to press against a roller which is in continuous motion. The finger-shaped contacts, or rubbers, on the scan arm meet contact tabs associated with each selector circuit, similar to those at the line end of the selector.



  When the contact fingers of the scanning equipment reach a line on which the dial operation has been completed, the equipment places the battery and earth across the circuit passing through the selector recorder network so as to that they are ready for operation on the line response relays that are

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 wish to call. The line circuit is arranged in such a way that when these response relays receive a momentary battery and earth pulse from the exploration circuit, the response relays are disengaged from the selector network.

   The scan pulse also caused the selector to complete its preparations for connecting the responding line by wedging in place a shorting contact across the third circuit appearing on the selector circuit legs. Associated with these timing contacts is an additional contact which closes and causes an operating arm associated with the selector circuit to begin operation. When the response relays of the called line disconnect from the selector recorder network, one of the response relays simultaneously started the movement of the arm; operation of this line by engaging its ratchet movement shaft and the rotating eccentric specific to this line.

   We now have the operating arm of the selector circuit and the operating arm of the line that the selector has called moving in synchronism.



  The selector circuit contact legs are arranged such that the selector operating arm closes a circuit through a relay coil and the previously latched contact to the selector multiple at the line equipment. With the called line operating arm having arrived at the selector multiple circuit at the same time, the circuit partially established by the selector is completed by the called line circuit where a hold relay and the line timing mechanism. responder are activated and the operating mechanism of the called line is made to lock.

   This circuit completion causes current to flow through a selector latch release relay coil and returns the stuck contact to normal, which opens the contacts it was holding in the closed position.

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 waiting for the called line to be put into communication. The opening of the contacts stopped the movement of the selector circuit operating arm by depriving its control relay of energy.

   An operating arm of the selector circuit then fell back to 3: its initial position. If the operating arm of the called line and the operating arm of the selector had not reached the same selector multiple together, the operating arm of the selector would have continued to a local contact tab which would have established a circuit releasing the locked contacts and supplying a warning circuit. An indicator would also have been activated to indicate to the maintenance personnel which of the selector circuits did not complete a communication.

   At the same time, the operating arm of the called line having failed to maintain synchronism with the operating arm of the selector, would be unable to establish the connection and would have continued its movement until the operating limit had been reached, and at that moment it would also have activated a warning device and would have wedged itself in place to indicate the faulty line. If other selectors have completed the dial operation on them, the scan arm does not return to normal but encounters each selector in turn, activates the called line and circuit operating arm. associated selector. When the operating arm reaches its operating limit, a trigger mechanism causes it to return to its starting point.

   It died during this return movement, since it is desirable to make the answering lines active in relatively the same order of succession as the selector equipment was picked up by the calling line. While one exploration arm is performing its return to normal motion, a second exploration arm can be activated by the triggering action of the first exploration arm.



  The second exploration arm was not included in the

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 detailed description.



   When the exploration apparatus places the hatterie and the earth on the circuit model or the recorder established by the operation of the dial, the battery and the earth are connected through the responding line relays of the line unit of the called line, if the line is not busy. If instead the called line is busy and battery and earth are applied by the scanning mechanism, the circuits cannot be completed by the relays of the responding line but a circuit is completed by means of a live circuit. parallel in the selector network. This parallel circuit is marginal and is unable to operate if the called line is found available.

   When the parallel circuit is not operating, it locks up and keeps busy on the calling line until the calling party disconnects.



   During the operation of the hold relay of an answering line, a circuit is closed in a ringing relay of the line circuit and the called station receives the signal by the operation of its ringing. This ringing circuit is that which is usually employed in telephone practice when machine ringing is used, an alternating current being superimposed on a direct current.



  When the called station is not in use for conversation, it maintains a capacitor across its line, which allows the component to. AC current to ring the bell but keeps the circuit open for the DC component. When the called party answers, direct current can flow and the line circuit bell relay is actuated and remains actuated while the call is established.



  The called line receives its battery supply from con-. versation by a relay in the line circuit. This relay is normally across the line to activate

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 the switchgear when a call arrives, but when the line answers, its situation changes and it performs the function of providing battery for the answering line.



   The main feature of the present invention is the apparatus employed to establish the numerical value of the line which is called and the initiation of this value into the line equipment to activate the line desired by the calling party. selector consists mainly of this equipment with accessory controls. When operating at a desired value in a ten thousand line telephone system, only three relays are in service. One of these three relays closes contacts in accordance with the value entered when the calling participant operates the dial.

   These contacts are arranged in four rows of fixed or recording contacts, one being activated by the operation of forming the dial miles, another by the operation of forming the hundreds, another by the operation. of formation of tens and the other by the operation of formation of the units to the dial. During each dial maneuver operation, a pulse absorbing relay is activated and maintains an open circuit until the pulses of a dial maneuver have been completed; at this moment it closes and activates the third relay which directs the next operation of maneuvering the dial to the correct row of fixed contacts.

   Upon completion of the four dial maneuvers, a series of contacts is closed in each of the four rows of fixed contacts and these series represent the numerical value determined by the dial maneuver. Assume that the desired row has the number 3498. Dial operations have closed the third contact group in the mile row, the fourth contact group in the hundreds row, the ninth contact group in the tens row, and the eighth group of contacts in the row of units. The first two operations of manceu-

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 vre of the dial have chosen the group of one hundred lines in which the desired line is located, namely the fourth hundred of the. third thousand.

   A ten thousand line system can be divided into groups of one hundred with one hundred lines.



  This is achieved in the present invention at the rows of fixed contacts. Each numeric value of ten units in the thousand row is divided into ten units in the hundreds row. When a unit of miles is activated it connects a common conductor which is across the units of the hundreds row. In this case, unit three in the mile row has been powered, which feeds a common conductor representing the third mile in the hundreds row. The fourth group of contacts in the row of hundreds having been closed by the operation of the dial, a circuit is then prepared to the group of a hundred lines in which the desired line is located. This circuit as it is now established is common to the group of a hundred lines chosen.

   This circuit is then established on a common conductor across the row of thousands of contacts on which the third series of contacts is closed, which extends the circuit on the third common conductor across the row of hundreds on which the fourth series of contacts. contacts is closed;

   has therefore established a circuit to the desired group of hundred lines. Another circuit to which the selection is made enters the equipment at the common conductor across groups of tens of contacts where. the dial maneuver had closed the ninth series of contacts, which in turn is connected to the ninth common conductor of the row of units, where the eighth group of contacts which is actuated completed the connection on the units side of the circuit to the ninety-eighth circuit of the hundred possible selections of the unit. It will now be assumed that this last circuit has been connected in multiple to the coils of all the relays in operation of line equipment whose

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 call numbers end with the digits ninety-eight.



  In systems with ten thousand lines there will be one hundred of these relays connected to this circuit. The first circuit of the pair of selectors which, as explained, is common to the group of thirty-four hundred lines, is multiple connected to one side of each of the line equipment relays in functioning of this group. The selection circuits have then been completed and are ready to be supplied. Associated with the row of unit contacts is a contact which closes with the first pulse of the units and normally keeps the selector circuits open when dial unit formation does not take place.

   To the row of fixed contacts of the units has also been associated a series of contacts which control a pulse absorbing relay which keeps the selector circuits open until the operation of the dial is completed, which prevents premature operation which could occur. result in the connection of an incorrect number. When the formation of the dial units begins, the scanning apparatus is activated if it is not already in motion as a result of the action of another selector. A contact that closes with the start of pulse operations of the units establishes a current in the operating magnet of the exploration equipment, which sets the exploration equipment in motion. - tion.

   The contact fingers or wiper of exploration equipment carrying the battery and the earth meet a series of contact tabs associated with each selector circuit and upon meeting a selector on which the operations dial operations have been completed, current passes through the contact finger to which the battery is connected in a contact lug and through one of the selector circuits, through a coil which controls a mechanically locked contact, to through the contact of the relay absorbing the pulses, through the ninth contacts of the

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 group of tens, the eighth contact of the group of units on the ninth common conductor, with output to the ninety-eight lines of each group of hundreds.

   The only line ninety-eight that has the other selector circuit completed by the selector recorder to its associated line relay is the thirty-fourth group of hundreds of lines. This last selector circuit is connected by contacts in the fourth group of contacts of the third common conductor of the hundreds row and by the common conductor and the third contact of the thousands group to the exploring contact lug. the selectors, a contact finger of the exploration arm and towards the earth completing the circuit. When the current described above has passed through the response relays of line 3498 it has operated these relays causing the operating arm of that line to begin operation.

   One of these response relays locks in the energized state and then opens the selector recorder circuits extending to these response relays. At the same time, the mechanically latched selector circuit relay, which has been energized in series with the other of the line response relays, closes a circuit through the operating magnet of the shift arm. actuation of the selector circuits, causing this arm to move in synchronism with the operating arm of line 3498. When the two operating arms arrive at their respective contacts in the multiple of the selector circuit, the operating arm. The 3498 line locks in place and that line is then connected to the appropriate calling line and selector circuit.



   The four rows of fixed selector contacts are returned to normal when the calling participant disconnects and the battery on a fixed contact of the selector release relay is held in two electromagnets until the four groups of contacts

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   selection have returned to normal; at this moment the return circuit is open.



   The answering line selector wires may be multiple-bound across as many rows of selector contacts as may be required for a given system. Fig. 1 is a block diagram of the system and indicates in general terms the processes and equipment involved in establishing and maintaining a communication between two rotary telephones, if used. of the automatic switching system to which the present invention relates.



   Each telephone is connected to the system by line equipment specific to the telephone. This line equipment can be used for calling into the system or for answering when the line is called.



   The selector circuits place the dial operation sound on the calling lines when those lines establish communication with a selector, select the called line when the dial operation takes place, and control communication between the calling and calling lines. - peeled.



   The scanning circuit controls the succession of communications to be established in order to avoid collisions and is common to the system.



   Referring to the freeze l, it will be assumed that a person at station A wishes to call station G. She lifts the receiver or hand-held device from her telephone, which powers the unit d line equipment Al. The line equipment unit is permanently associated with its line.



  The line operating arm M which is a part of its line equipment unit immediately begins to move upward to cross the connection multiple in search of a free selector circuit. Multiple selector circuit contacts that appear in each row are indicated as Q. When a circuit is found

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 free selector, we will assume that it is J, the line operating arm M stops moving and is locked in place as shown in M-1 in the diagram. With this connection between the line calling and the selector, the dial operation sound is established on the calling line and the calling subscriber at A, while waiting for this sound, operates his dial according to the indicative number of the line he wishes.



  The values formed on the dial in the selector circuit J are placed on switches or recorders in accordance with the operations of the dial. These switches set $, send circuits through the select recorder network to the desired line but the circuits are not,! not supplied until the exploration operation has taken place. The scanning equipment 0 is powered by the last operation of the dial in one selector or may already be in action as a result of the operation of another selector.

   When contacts on exploration arms B meet the exploration contacts of selector circuit S by moving across them, the operating arm of the called line is activated if the operation of the dial has been activated. complete. The circuits in the selector network on the desired line equipment are energized and the line equipment operates in its called or answered state. The operating arm M of the desired station, in this case G, is activated and begins to move upwards towards the connection multiple.

   When the scanning arm P fed the circuit to the called line, it simultaneously caused the power to the selector operating arm N or the selector circuit J, at the beginning of its upward movement towards the multiple. connection. The equipment line operating arm J-1 and the equipment selector operating arm J then move in synchronism and reach the connection multiple contacts Q of the selector circuit J at the same time. By doing this the operating arm

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 line locks in place and automatically rings the telephone ringing at set G.

   Line operating arm M of line equipment A-1 remains on contact legs Q of the selector circuit until the call is complete or the calling party disconnects. The operating arm of the selector circuit N drops out after having completed its operation, escorting the called line to the correct circuit in the multiple connection.



   The detailed descriptions which follow will cover many details not touched upon in the foregoing brief discussion. Busy indication, overload recording, fault indication, reversion ring tone and bell control as well as other essential features will be presented along with detailed device descriptions. mechanical and electrical which form part of the present invention.

   It is further believed that with this description and those which follow showing how communications can be established between office lines of the same quality, it will be readily understood that other details of operation normally occur. in a large central office, such as office trunk lines. information lines, service observation circuits, lines to operator stations, test circuits, pay trunk lines, long distance lines and so on can be incorporated without difficulty in this system and it has not been considered necessary to add descriptions and drawings of these features and others which do not influence the realization of the basic system office line switching.

   The sources of energy supply and the orders have no influence on the realization either.

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 of this system and when a battery has been indicated, it can be assumed that it is the usual 48-volt accumulator battery in use in central telephone offices.



  When reference is made to ringing current, busy sound or dial operation sound, it will be assumed that the frequencies and operating intervals usually in use are applied.



   Mechanical details of the line equipment unit
Bearing in mind the foregoing general description of the invention and of the apparatus employed, the invention will now be considered in more detail.



   The essential mechanical details of the line equipment unit are shown in figs. 9,10,11,12 and 13. Fig. 9 is an elevational view showing that the unit is enclosed in a metal support frame 901 and is suspended from a metal frame above it. It can be seen that the removal and replacement of the line unit will be relatively straightforward operations.



  Two spacers 931 and 973 extend across the support frame 901 and also serve as a support and guide for the equipment. Inside the support frame 901 is placed another rather complex frame. Its upper end consists of a cross member 985 which carries contact fingers or wipers 987, 988, 989, 992, 993 and 994.



  Its sides are mainly composed by switch bands 951, 952, 953, 956, 957 and 958 and their insulation and supports. The lower part of the frame consists of a flange which is provided to hold the frame rigid. In the middle of this inner frame, but without fixing; a guide bar 940 has been provided to keep the inner frame in alignment as it is raised and lowered. A rack 933 lifts the inner frame and is enclosed in a guide channel 932; a locking plate 934 functions to hold the inner frame at any desired level when it has been brought into position by the

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 rack.

   The shaft 921 with its associated control pawl 924 raises the inner frame by moving its finger-shaped contacts across fixed contacts provided in the multiple of connection of the selector circuit shown in fig. 2 , 3 and 4. For each unit of line equipment, a continuously rotating cam 905 is provided. When a line equipment unit is activated, this cam 905 provides the reciprocating motion necessary for the operations of the ratchet mechanism.



   The lower end of the ratchet bar 921 carries two mounts 917 which is permanently attached to the bar 921 by the rivet 920 and 918 which has a short handle 919 extending into the mount 917. A the attached to the lower end of the frame 918 is a wheel 909.



  This wheel 909 reduces friction when the irregular contour of cam 905 is followed by the ratchet bar during operation.



   The upper member of the inner frame is the cross member 985 appearing in FIG. 9. It is made of insulating material and has two sets of three contact fingers or wipers, one set at each end. Contact fingers 987, 988 and 989 are at one end and contact fingers 992, 993 and 994 are at the other end. The two groups of contact fingers are held in place by grooved pieces of insulating material 986 and 991. The grooves are provided in the lower space of the pieces 986 and 991, as can be seen with reference to FIG. 12. These grooves keep the contact fingers in alignment. Part of the cross member 985 and part of the part 991 are shown with a break in FIG. 9 to show a typical 969 screw and its 968 insulating sleeve.

   The screws holding parts 986 and 991 in place are of the automatic pitch type

  <Desc / Clms Page number 25>

 Small notches are necessary in the sides of the material and contact fingers at the location of the screws to allow the sleeve and the screw to be installed, as has been shown. These notches are not shown and can be omitted if the contact fingers and the associated contact tabs of the selector circuit in FIG. 2 are sufficiently spaced to place the sleeves. This, however, is not desirable because the overall length of the installation of a number of line units is increased considerably.



   Three electromagnets 501, 502 and 504 are mounted on the left side of support frame 901. When these electromagnets are energized, they activate certain mechanical devices, in addition to operating contacts for electrical functions. . These electromagnets will be called relays in the following. The relay 501 with its armature attached to a bat 1306 shown in FIG. 13.Relay 501 is energized when a call arrives. It is also energized while the called extension is connected.



   Relay 504 has its armature attached to a bar 906 which is disposed and equipped in a manner analogous to bar 1306 of relay 501. Bar 906 associated with relay 504 is shown in FIG. 9 only.



   The situation of the contact groups of relays 501 and 504 is shown at 981 in FIG. 9. The relay contact group 504 is shown in part at 981 and the relay contact group 501 is located immediately behind and parallel to the contact group 981.



   Bars 906 and 1306 are normally in the same relative position and the apparatus which they carry is identical except that their main elements are turned inward to allow common engagement with certain parts of the apparatus; as will be explained.



   Each of the bars 906 and 1306 is a little larger at

  <Desc / Clms Page number 26>

 the contact end than the end facing the relay. The sliding pieces 914 and 1314 are fitted on the small end of the respective bars 906 and 1306 and held against the widened part of the bars by springs 915 and 1315. Each of the bars 906 and 1306 has a similar pin, shown only on the bar 1306 in 1307. The sliding members 914 and 1314 normally maintain a slight pressure on their respective springs 915 and 1315 as a result of the pressure of their respective contact springs 981, exceeding the pressure of the springs 915 and 1315. This pressure margin acts only when the respective relays 501 and 504 are de-energized.



   The sliding members 914 and 1314 have a shape such that a flange 1359 extends transversely to their interior side. This flange presses against the latch 908 when the bar 906 or 1306 is moved by the operation of the associated relay. When a bar 906 and 1306 is moved towards the groups of contacts shown at 981, the sliding member 914 or 1314 of the bar moves with the bar as a result of the pressure of its spring 915 or 1315, these two springs being made of a flat spring material and being suspended from the underside of spoke 973.

   When the slider reaches the latch 908, the latch 908 is moved in the direction of the frame 918, until a ledge of the lower end of the latch 908 rests against the frame 918. The displacement of bar 906 or 1306 also obliterates a pin of the respective bar, shown at 1307 in bar 1306; to move with the bar. When moved, this pin raises the latch 910 from the notch 911 provided in the mount 918. The latch 910 is made of a flat spring material, suspended from spoke 973 and normally holds light pressure against mount 918. Spring 916 is made of elastic wire and also hangs from shelf 973 although the fastener is not shown.

   This spring 916 has a tension such that it

  <Desc / Clms Page number 27>

 normally keeps the latch 908 away from the mount 918.



   When the latch 910 is moved away from the notch 911, the frame 918 is free to move downwards and is urged to do so by a wire spring 913. As mentioned previously, the cam 905 is in constant rotation, so that the wheel 909 of the frame 918 contacts its contour and follows it as the frame 918 moves downward. For a low location around the edge of the cam 905, the slot 912 of the mount 918 will have been moved down to a point where it engages the tip of the latch 908. When the edge of the latch 908 enters slot 912, mounts 917 and 918 are mated and ratchet bar 921 is raised and lowered in a reciprocating motion as wheel 909 follows the varying contour of oame 905.

   This action continues while the coupling is maintained and the hold relay, explained later, is not actuated.



   Fig. 10 is a partial cross section of the line equipment unit at a point immediately below cross member 985. For clarity, wires 995 have been removed in this view. In Figs. 10 and 11, the retaining pawl 925 is shown near the actuating pawl 924. As the ratchet bar 921 moves upward, the actuating pawl 924 which rests. normally immediately below the upper tooth of the rack 933 also moves upward and lifts the rack 933.

   The upper end of the rack 933 engages the underside of the cross member 985 and therefore when the rack 933 lifts the entire frame.

  <Desc / Clms Page number 28>

 interior is also raised.



   The reciprocating motion of the actuating pawl 924 and the retaining action of the pawl 925 preventing reverse motion is an operation usually in use so that a detailed explanation of slippage, clearances, etc., should not be given. The actuating pawl 924 pivots on pin 999 of the bar 921 and is held with slight tension against the rack 933 by a wire spring 926 supported by a bracket which is part of the spacer 931. A pawl to re. Hold 925 pivots on the aforementioned bracket which is part of spacer 931, and is held under slight tension against rack 933 by wire spring 927.



   The languor of the teeth in the rack 933 and the lifting distance in the contour of the eccentric 905 are controlled by the sliding requirements of the rack, the play of the pawls, and by the vertical distance between two similar end legs. in the multiple of the selector circuit which is located above the line unit and engages the contact fingers 987, 988, 989, 992, 993 and 994.

   Referring to fig. 2 and 4 it can be seen that when the contact finger 987 rests on a contact tab 202, the contact finger 988 rests on a contact lug 203, the contact finger 989 rests on a contact lug 204-, the contact finger contact 992 rests on contact 404, contact finger 993 rests on contact lug 405 and contact finger 994 rests on contact lug 406 These six engagements represent the linkage in line equipment to selector equipment . To connect the same line equipment to the selector circuit immediately above, it is necessary to lift the contact arms until they engage with the similarly numbered contacts,

  <Desc / Clms Page number 29>

 appearing immediately above.

   Each cycle of ratchet motion must provide this amount of lift on the upward motion to bring the contact arms into full engagement with a different selector circuit on each upward advance.



   A stopper 922 has been introduced in bar 921 to limit downward movement of this bar when engaging the console shelf 973.



   The lower portion of rack 933 contains pin 937. When rack 933 is in the normal or down position, pin 937 passes through a hole in a shelf which is part of spacer 973 and engages with it. contact group 938 while maintaining the contacts under voltage. When the rack 933 is lifted, the pin 937 rises with it and the group contacts 938 operate accordingly.



   Figs. 10 and 11 show an L-shaped piece of metal 934 which forms part of the inner frame and is held in place by screws, the heads of which are seen in FIG. 9, based on parts 950 and 985.This part in the form of LI. is intended primarily to support guide ohenal 932 which is welded in place and to provide notches.



  935 which are used in holding operations. These notches 935 are the same number and have the same spacing as the teeth of the rack 933. The L-shaped part 934, part of the inner frame, is raised and lowered with this together.



   Associated with relay 502 is a bar 928 which carries a slide member 930 and a latch 929. The top of the bar 928 is arranged to form a. arm-shaped projection which extends across the inner face of pawls 924 and 925. This arm can be seen more clearly in fig. 11.

   Bar 928 is also associated with contact group 980 so that when relay 502

  <Desc / Clms Page number 30>

 is energized, the contact group operates to move to the actuated position as a result of the armature of relay 502 moving bar 928 slightly, which applies pressure to the springs of contact group 980. is
The bar 928 / a little wider at its contact end than at its end facing the relay. At this latter end the sliding member 930 rests against the end of the enlarged part under pressure of spring 949.

   Since the pressure of the spring 949 is less than that of the contact group 980, the pressure of the contact group 980 normally maintains the bar 928 in the position shown in FIG. 9 when relay 502 is de-energized. It should be noted that the sliding member 930 is kept away from the L-shaped part 934 when the bar 928 is in the normal position. The sliding member 930 has a lip or a rib on its internal face, similar to that of the sliding member 1314, shown in FIG. 13 in 1359.

   When the relay 502 is energized, its armature forces the bar 928 to move towards the group of contacts 980, which actuates the contacts and at the same time makes the sliding member 930 move in the direction of the contacts 980 until that its lip rests against the L-shaped piece 934; at this point, it is stopped while the bar 928 continues its movement to the maximum.



   The arm extending at right angles to the bar 928 and associated with the pawls 924 and 925 causes these pawls to move away from the rack 933 against the pressure of the springs 926 and 927 as the bar 928 advances. Latch 929, made of a flat spring material and attached to bar 928, has a lip at its lower end which is pressed against ratchet bar 921 and engages a notch 923 at the tip of the latch. upward movement of the bar 921, which keeps the snap bar assembly substantially away from the eccentric wheel 905.

  <Desc / Clms Page number 31>

 



   When the pawls 924 and 925 are moved away from the rack 933, the latter is no longer supported and therefore falls into its initial position in the guide channel 932, with its lower end resting on the shelf of the spacer 933 and its pin 937 activating the contact group 938.



   The relay 502 is caused to operate by certain circuits established by the engagement of the line unit contact fingers and the contact legs of the multiple of the selector circuit. This relay is intended to maintain a desired connection between the line unit and a selector circuit and therefore its operation is set to occur immediately after a notch 935 of the L-shaped part 934 has passed opposite. of the lip of the sliding member 930 in an upward movement so that with a few clearances of the oliquets 924 and 925 and a second subsequent downward movement of the inner vadre, this lip engages in a notch 935 and keeps the inner frame in place throughout a connection.



   When a call is completed and the relay 502 is deenergized and the bar 928 returns to its normal position as a result of the pressure of the contact springs, the widened end of this bar which is in engagement with the component of sliding 930 causes it to disengage from notch 935 of L-shaped part 934. Pawls 924 and 925 resume their first position with their points resting against rack 933 immediately below its tooth higher due to the displacement of the arm of the bar 928 which had retained them and due to the pressure of the springs 926 and 927.

   The lip of the Imquet 929 disengages from the notch 923 of the ratchet bar 921 with the return of the bar 928 to normal, allowing the ratchet bar 921 to drop.

  <Desc / Clms Page number 32>

 



   When the slider 930 on the bar 928 disengages from a notch 935 of the L-shaped part 934, the entire inner frame of the line unit is unsupported and therefore the assembly falls towards its normal position in which it rests on the top of the rack 933 which had fallen previously when the locking operation by the relay 502 took place.



   The helical springs employed to produce the downward movement of the rack 933, and the downward movement of the inner frame are not shown in the figures.



   When a line unit is used in an incoming call operation, its relay 501 is actuated until the hold relay 502 is energized; at this moment, the relay 501 is de-energized. When the relay 501 is de-energized, its bar 1306 returns to normal, the lip of the sliding member 1314 releases its pressure on the latch 908 and therefore its lip is caused to disengage from the notch 912 as a result. of the action of the spring 916. At the same time, the pin 1307 has returned to its normal position releasing the latch 910 and allowing it to return to a position where its lower end rests against the mount 918.

   When the mount 918 rises to the maximum as a result of the action of the eccentric 905 the latch 910 falls into the notch 911 which keeps the mount 918 substantially spaced from the eccentric 905. The group of associated contacts also returns. to its normal position.



   When a line unit is employed in an answering operation, relay 504- is energized and remains energized until the call is released. Relay 501 also operates when the called station answers, but its primary function in the answering circuit is to supply the conversation battery to the answering station. All of these ratchet control operations take place when relay 501 is energized for its response operation, but they

  <Desc / Clms Page number 33>

 are not effective because similar operations were previously performed by relay 504.



  When, however, the calling station disconnects, the relays 501 and 504 of the answering line unit drop out together, the bars 906 and 1306 resume their normal display; the sliding members 914 and 1314 relieve their pressure on the latch 908 which is released from the notch 912, the latch 910 engages in the notch 911 as a result of the displacement of the pins 1307 and 907 and of the corresponding pin (not shown) associated with bar 906. Frame 918 is locked in its raised no position. veal.



   A mechanism is provided to return the inner frame to its normal position when the contact fingers of the line unit have passed fully across all contact legs of the multiple of the selector circuit in the arrival operation. This mechanism also controls the locking of line equipment and the production of an audible signal when a line unit does not connect to its calling line during the line unit answer operation .

   In this specification it is referred to as the trigger mechanism and is shown mainly in figs 9 to 14 to which reference will now be made. It can be seen that the springs on the outside of the group of contéots 982 consist of flat springs 947,948 which interlock at the upper end. These two springs are energized towards the L-shaped part 934 but do not quite touch it. The horizontal section of spring 947 is also tensioned slightly upward. Towards the bottom of L-shaped part 934 and the spaced side of guide channel 932, pin 945 advances to contact group 982 and is long enough to meet the bump of spring 948. near its base.

   Vertically, pin 945 is placed

  <Desc / Clms Page number 34>

 so when the contact arms have passed through all of the selector circuit contact tabs, subsequent operation of the ratchet mechanism causes this pin 945 to flow over the spring boss 948 which pushes this pin 945 through the spring boss 948. spring to the other springs of the contact group. This movement of the spring 948 has caused its upper end to move outwardly past a step in the spring 947 which, being tensioned upward, causes the two springs to wedge together. This movement of the spring 948 also caused the contact springs to operate towards their actuated situation.

   As the pin, 945 was lifted and approached and engages the bump of spring 948, pin 946 was moving away from its normal position in which it rests on the end of spring 947. .



  Operation of the contact springs 942 caused the upward movement of the L-shaped part 934 and caused the associated inner frame to stop and then return to its original position. Upon reaching and engaging the tip of spring 947, pin 946 presses the end of this spring down enough to disengage its step from engagement with spring 948, causing that spring to return. in the initial state and the contact springs 942 to return to their non-actuated position.



   The spring assembly 982 is supported by a bracket 954 attached to the shelf formed by the spacer 97.



   On each side of the frame assembly surmounted by cross member 985, three thin strips of conductive material are mounted to serve as a switch to maintain electrical continuity to contact fingers 987, 988, 989, 992, 993 and 994 during the ratchet operation and when contact fingers have reached the position

  <Desc / Clms Page number 35>

 desired. These switch bands are numbered 951, 952, 953, 956, 957, 958 and are shown in Figs. 9,10 and 11.



  They are separated by strips of insulating material 971 and lined with insulating strips 950 and 955. Machine screws with an insulating bush hold the two assemblies together by attaching them to L-shaped part 934, to a flat metal piece 972 and a cross member 998.



  Parts 933, 972 and 998 are drilled and tapped to accommodate machine screws. Each switch strip has a brush resting on it under a certain voltage. These brushes are shown in FIGS. 9,10 and 11 and are numbered 960, 961, 962,965, 966 and 967 and are made of spring material. To hold the brushes in place on the switch bands the ends have been shaped with a letter U. The brush mounts are shown at 970 and 975 in Figs. 9 and 10. These mounts are arranged and held in place in the same manner as the parts 986 and 991 shown in FIG. 9 and described elsewhere.



  The lower end of each broom is folded back so that it extends into a slot in the line unit frame 901.



  The outer end of each brush is drilled to act as a terminal by attaching a wire. The top end of each switch strip 951, 952, 953, 956, 957 and 958 is drilled for installation of wires 995 extending to contact fingers 987, 988, 989, 992, 993 and 994. through holes drilled in cross member 985 and through openings immediately above the switch strips.



   Multiple selector circuit equipment.



   The foregoing descriptions have indicated the selector circuit multiple contact legs, including 1a. arrangement is shown in fig. 2, 3 and 4. Lafig.2 is an elevational view of one side of the multiple of the selector circuit as it appears from the internal side. Each line equipment in the system is associated with three rows (green) ,;

  <Desc / Clms Page number 36>

 contact shims on each side of the selector circuit multiple.

   This will be understood more clearly by referring to fig. 4 concurrently with fig. 2. Figure 4 is an end view of the multiple selector circuit equipment in which the row of fixed contacts 201, and its analogue the row of fixed contacts 410 form the two side walls of a corridor. At regular intervals, as indicated at 210, 211 and 212 in Fig. 2, three vertical sets of contacts of each row 201 are aligned with a series of three contact fingers of a row unit. .

   In other words, one half of the contact fingers of each line unit, namely 987, 988 and 989 engages the selector switch tabs on one wall of the corridor and the other half of the contact fingers. of the line unit, namely 992, 993 and 994 engages the selector contact tabs on the other wall of the corridor. Figure 3 is a plan view of one half of the selector circuit multiple contacts for a system employing only one pair of rows of fixed selector circuit multiple contacts.



  With three vertical series of contacts representing the longitudinal requirements for a line if the system exceeds for example 50 lines, the rows of fixed selector contacts are assembled accordingly in sections and wiring points of the strips 202, 203 and 204 and their equivalents 404, 405 and 406 in the opposite row will be split at each end of the row for the installation of a coupling wire between the sections. If multiple, selector contact sections are used, mappings can be arranged in the coupling wiring between multiple sections of the selector circuit and in the line circuit wiring to reduce the capacitance effect in the selector circuit. a long multiple of selector circuit.



  It will be noted in fig. 3 that the multiple bands of cir-

  <Desc / Clms Page number 37>

 selector switch holes are considerably narrowed in places where material is not required for mounting screws, contact lugs and wiring terminals. The shrinking of the material in each selector circuit multiple band to the minimum width compatible with robust construction and low electrical resistance also tends to reduce the capacitance effect between the selector circuit multiple bands.



   Typical mounting screws are shown in Figs. 3 'and 4 at 302 and typical insulating sleeves for mounting screws 302 are shown at 301 in Fig. 4.



   Flanges 400 and 401 suspended from the frame of bracket 403 of the type commonly employed in buildings or telephone cabinets hold the multiple selector circuitry in place. These 401 brackets are drilled and tapped for attaching 420 and 425 angles which are drilled and tapped to each line equipment for attaching 901 support frames of line units and to each 302 mounting screw to hold rows in place number of fixed contacts of the selector circuit multiple.



   In fig. 4, the plates 402 cover the entire selector circuit multiple. They are drilled at the location of the screws 32 for mounting and at each line equipment unit to hold the guide bar 940 of each line unit in place.



   It can be seen by referring to figs. 2 and 4 that the multiple 201 of the selector circuit contacts and its equivalent 410 may be made up of successive layers of insulating material between the multiple selector circuit contact strips 202, 203, 204, 404, 405 and 406 with insulating strips at the top and bottom of the stacks, or its insulation may consist of molded plastic.

  <Desc / Clms Page number 38>

 



   Electrical details of line equipment unit.



   In the foregoing description of the mechanical details of the line equipment unit it has been deemed necessary for the sake of clarity to introduce some of the characteristic electrical details. In describing the electrical details it will now be necessary to understand some of the mechanical operations previously described. Fig. 5 shows in schematic form the circuit of the line equipment unit and contains sufficient mechanical details, also in schematic form, to show the relationship between the mechanical and electrical operations.



   In the description of the operation of the circuits of the line equipment unit, it is necessary to introduce certain details of a selector circuit so that if we refer in common to figs. 5,6 and 15, a better understanding of the operations can be obtained.



   A single line equipment unit is used for call and answer line operations. In the calling operation certain circuits are established by the line equipment unit through which the calling subscriber can, by operating his dial, connect his line to any desired line in the system. In the answering operation, its line equipment unit responds to call operations directed therein by another calling line.



   One unit of line equipment is provided for each station in a system: For example for a line with four participants four units of line equipment would be required for answering purposes. Three of the four equipment used for a four party line will have their call details disconnected. The disconnection of the call details can be done by opening two wires at the point indicated by 540 in fig. 5 or by placing

  <Desc / Clms Page number 39>

 thin pieces of insulating material in breakage contacts 581 and 583 connected with these wires to latch relay 502. Reference numeral 511 in fig. 5 indicates the location of the main terminals of the distribution frame and wires jumpers in the circuit.

   The reference number 550 is the location of the intermediate terminals of the distribution frame and jumper wires in the circuit. An intermediate distribution frame will only be necessary when the system must serve participant lines.



  The various line equipment units assigned to a line will be bridged to the line at this point. Terminals are provided at 518 in FIG. 5 to link the different generator ring frequencies 515 to the line equipment units in accordance with the ringing requirements of the participant line.



   Call operations through a line equipment unit
It will be assumed that a call operation takes place from a station in a system including the apparatus to which the present invention relates. For this purpose it is necessary to refer to fig. 5 which represents a typical line circuit. Assume first that the telephone located at 510 of FIG. 5 is employed in the calling operation and that the receiver has been lifted.



   For the purpose of description, the negative terminal of the system central office battery will be referred to as the "battery" and the positive terminal, which is usually grounded in practice, will be referred to as the "earth".



   The conversation circuits are shown in fig. 5 by strong lines. We see again in fig. 5 that at relay 501 the battery and the earth are normally found on the windings of this relay: A circuit coming from the battery by a breaking contact of the group of contacts 982

  <Desc / Clms Page number 40>

 by a winding of the call relay 501, by a break contact 583 of the latch relay 502, by one side of a jumper from IDF to 550 if an IDF is used, by one side of the MDF jumper or the jumper of linkage rack in 511, by the telephone in 510, by the other opted for the MDF jumper or the linkage rack in 511, by the other side of the IDF jumper in 550 by a breaking contact 581 on the locking relay 502, by the other winding of the call relay 501 and towards the tare.



  Completion of this circuit operated call relay 501 and its bar 1306 to begin the rack actuation operations described with the mechanical details of the line equipment unit shown in Figs. . 9, 10, 11, 12, 13 and 14. The rack operations raise the inner frame which has been previously described and which can be easily found by the reference numbers in FIG. 5, and each upward rack advance lifts the inner frame correspondingly to engage the contact fingers 987, 988, 989, 992, 993 and 994 with their respective selector circuit multiple contacts 202 , 203, 204, 404, 405 and 406.

   Two selector circuits and an aspect of their multiple contacts are shown in fig. 6.The selector multiple contacts are shown as short solid lines in fig. 6 and 15. Relay 502 is of a type established for slow release, so that it does not drop out during the interval of the dial pulses.



   It should be noted here that the groups of contacts shown in FIG. 9 at 980 and 981 for relays 502 and 501 504 respectively are shown in fig. 5 as individual contacts. Thus group 980 associated with relay 502 is shown in Fig. 5 as individual contacts 580 to 589.

  <Desc / Clms Page number 41>

 



   It is now necessary to assume that the first selector circuit encountered by the contact fingers of the circuits of the calling line has been found free.



  Referring to fig. The selector circuit multiple strip 406 i is found to be grounded to the break contact 1582 of relay 1503. When the trotter of the contact finger 994 in FIG. 5 met the contact tab of selector circuit strip 406 in FIG. 6, a circuit has been established from the battery on the winding of the lockout relay 502 in fig. 5 by the winding of this relay to a break contact 577 on the relay 504, by the closing contact 592 of the relay operated line 501, by brush 967, by switch strip 958, finger 994 of selector circuit multiple strip 406 in Figs. 6 and 15, by a break contact 1582 of the relay 1503 towards the earth, which brings the latching relay of the relay 502 of fig.



  5 operate and perform its locking functions by activating its bar 928, as described in connection with the mechanical details of the line equipment unit.



   The calling line contact fingers are then on what had been a free selector circuit.



  To prevent other calling lines from connecting to the same selector circuit the following features are provided. As a result of the operation of the 50µ locking relay in fig. 5, the calling line from extension 510 which was on closing contacts open to relay 502 is now extended and the calling loop to extension 510 established on contact fingers 987 and 988 by brushes 960 and 961 and switch bars 951 and 952 is now extended by relay 1501 of fig. 15 on the selector circuit multiple bands 202 and 203 of FIGS. 6 and 15. The battery and

  <Desc / Clms Page number 42>

 earth are located in the windings of relay 1501, which operates this relay by means of the calling loop.

   As a result of the operation of relay 1501 a circuit is closed in 1561 for the slow-to-operate relay 1502, followed by 1503 due to the closure of 1563.



  Relay 1503, while operating, in 1582 removed the battery in band 406 from the selector multiple.



   When the relay 502 of fig. 5 operated, it closed four make contacts and opened six break contacts. Two of the make contacts closed the talk circuit through the selector circuit, as previously described. The third make contact places earth on the bell circuit which is on the winding of relay 505 but is currently open to close relays 572 of relay 504- and therefore has no action in the equipment calling unit. line.

   The fourth closing contact 588 of the relay 502 closes by the earth located on the coil of the relay 502, and extends this by the brush 966, by the switch strip 957, by the contact fingers 993, by the selector multiple band 405 of fig. 6 and 15, by a closing contact 1581 on the relay 1503 where it meets the battery, which maintains the relay 502 of FIG. 5 in the actuated state throughout the time that the calling loop is maintained across the relay 1501 of FIG. 15 by the calling station 510.



   Two of the break contacts 581 and 583 of relay 502 are in the battery and earth circuits through the winding of relay 501 and extending to the telephone at 510. Due to operation of relay 502 that has occurred , this opening of the battery and earth circuits by the winding of the relay 501 drops this relay and interrupts the ratchet operating operations of the line equipment unit.

   When operating the re-

  <Desc / Clms Page number 43>

 502 the locking and ratchet lifting actions of bar 928 in the line equipment unit have also taken place and the inner frame of the line equipment unit remains in engagement with the selector circuit which He found, except that the rack 933, being no longer supported, fell back until its pin 937 opened the contacts 935 which had operated in the first ratchet operation.



   It should be noted that the calling relay 501 of fig. 5 activates, when it is energized, two breaking contacts and one closing contact. Note also that the calling relay 501 was energized while a calling line was looking for a free selector circuit. One of the break contacts 591 of the calling relay 501 opens a circuit to the battery through the coil latch 502, the brush 962, the contact finger 989, the contact strip 204 of the selector multiple of figs. 6 and 15 and to the response control contact 1520 in fig.15.

   When line equipment is operating as a response line, there is a short interval when contacts 1520 and 1521 are connected and earth is established on control contact 1520, thus preventing faulty operation of the 502s relay. It was encountering a selector circuit during the short interval where earth is on the conductor in question. The conductor is kept open in the line equipment when they perform their calling function.



   The other break contact 590 associated with relay 501 of FIG. 5 opens lead 530 in the answering line model circuit for that particular line, so that if the line is called during the call, a busy signal results. When the hold circuit 502 operates and the calling relay 501 is de-energized, the other responding line model circuit is held open by the break contact 585 at the relay 502. One des-

  <Desc / Clms Page number 44>

 Full description of occupancy test details can be found elsewhere in the specification.



   The closing contact 593 of the calling relay 501 is in a circuit shown entirely in FIG. 5, from the battery on a winding of the locking relay 502, through contacts 593 and 577, to a closing contact in the group of contacts 938, to a closing contact in the group of contacts 982 and to the earth by the recorder 503. This circuit can operate to cause the operation of the recorder 503 only when the contact fingers of a line equipment have passed through all the selector or system circuits, during a call operation, without finding a free selector circuit.

   When the rack is lifted by the mechanical operations following the operation of relay 501 in its calling action as previously described, pin 937 attached to rack 933 is lifted from its engagement with contact group 938 which makes these contacts close. The operations of the rack also lift the entire inner frame, so that pin 946 is at the top of the top is moved away from its engagement with spring 947 and pin 945 approaches the bump of spring 948 when operating operations. rack continue. The springs 947 and 948 comprise the tripping mechanism described previously during the mechanical operation of the line equipment unit.

   When the contact fingers have passed through all of the selector circuits, pin 945 is located such that it engages the bump of spring 948 during subsequent advancement of the rack, causing the spring to engage. engaged with spring 947 and maintaining the contacts of group 982 in an actuated position, with two contacts closed and one open. When the pair of contacts

  <Desc / Clms Page number 45>

 of. group 982 associated with the recorder 503 is closed) the recorder 503 is energized at the same time as the restraint relay 502.

   The operation of the relay 502 and the corresponding actuation of its bar 923 caused the detent operations previously described, the inner frame remaining in the raised position and the rack 933 falling back, in its normal position in which the pin 937 actuates the group of contacts 938. The opening of the group of contacts 938 causes the de-energization of the retaining relay 502 and of the recorder 503; therefore, with the retainer operations being interrupted, the inner frame drops back to normal and pin 946 lands on the tip of spring 947 and pushes it back, allowing spring 948 to escape to its original position, which opens two contacts of group 982 and closes the other.



  The contact of group 982 which opened when the spring 948 wedged against the spring 947 cut off the battery supply to the relay 501, which suspended all the ratchet operations until the inner frame has returned to normal and has closed this contact in group 992. The calling subscriber, who is still waiting, forces relay 501 to operate again and the ratcheting operations to lift the contact fingers again in through selector circuits in search of a free selector circuit. Recorder 503 is the type currently in common use in telephone offices for recording messages.

   The readings on recorder 503 tell people that this relates to the number of times line equipment has passed the selector circuit without finding a free selector circuit. The 503 recorders are installed in common for a group of lines.



   When the relay 1501 of fig. 15 has been activated following the connection of a calling line, the relay 1501 has caused the operation of the relays 1502 and

  <Desc / Clms Page number 46>

 1503 by clearly visible circuits. The dial operation sound on conductor 1567 is fed into the receiver of the calling telephone which indicates to the calling subscriber that he can begin dialing the calling number of the line he wishes. Driver 467 is cut off from the dial operating sound produced by a break contact 495 in contact group 1578 which is actuated by rack 1643 explained later.

   The dial maneuver sound will be heard by the calling subscriber in the intervals between dial maneuver operations, but will not be heard when the dial maneuver has been completed and the calling subscriber is awaiting the call. connection of the called line. When the called line is connected, the calling subscriber hears the ringing tone in return while waiting for the called line to answer. This will be explained with answering line operations by means of a line equipment unit.



   Response operations by means of a liana equipment unit.



   It will be assumed that a calling subscriber line is connected to a selector and that the subscriber has completed the dial maneuvering operations to choose a desired line and that the line circuit of the line he is calling is similar. to that of FIG. 5. Shortly after the dial maneuvering operations were completed, earth was momentarily applied to conductor 532 of fig.5 and at the same time the battery was momentarily applied to conductor 530 of fig. 5. The means employed to select the desired line and the introduction of the battery and the earth will be described with the selector equipment and the circuit elsewhere in this specification.



  The earth coming from the scouring switch wiper 1550 is extended by the selector network to the conductor 532 and by the rupture contacts 574 and 585 and.

  <Desc / Clms Page number 47>

 by winding the relay 504 'towards the battery in order to operate the relay 504' with a view to connecting the earth to the relay 504. The battery is extended from the scraper 1551 of the scanning switch by the selector network having operating which has registered the called line, the conductor 530 and from there by means of the contacts 590 by the winding of the relay 504 towards the earth to the contacts 579. The relay 504 'activates and to the contacts 575 it completes a locking circuit with its right-hand winding, while at contacts 574 it opens the circuit to relay 504 'which then de-energizes.



   With the operation of the relay 504, its bar 906, in addition to having actuated the contacts of the groups 981, caused the start of the various latching operations and consequently the upward movement of the inner frame of the unit. line equipment.



   The battery supplied to the driver 530 of FIG. 5 for the operation of the relay 504 'passes through the winding of the relay 1508 of FIG. 15, which makes this relay operate at the same time as the relay 504 of fig. 5.



   The relay 1508 of fig. 15 carries three closing contacts 1573, 1574 and 1579 which are mechanically locked in their actuated positions when relay 1508 is energized. These contacts remain locked until relay 1509 is energized and disengages them.



   When the calling line has established the connection with the selector circuit in fig. 15; relay 1503 was energized and the battery supplied by its closing contacts 1588 was on closing contact 1574 of relay 1508.



    From the operation of the relay 1508, this battery is connected to the earth by the contacts 1579 and the winding of the relay 1510, which energizes the relay 1510 and does so as the snap-in operations of the arm actuating the circuits. selectors by causing the contact fingers 1535, 1536 and 1537 to move upwards.

  <Desc / Clms Page number 48>

 



   The selector multiple strip 404 is connected to the other latched closing contact 1573 of relay 1508 so that by operation of relay 1508, selector multiple strip 404 is connected to control contact 1521. response by closing contact 1573 of relay 1508.



   The mechanical construction of the selector circuit operating arm is essentially the same as that of the line equipment unit and it has therefore been deemed unnecessary to provide a second description of the details of all its features. However, the differences between the unit used in connection with a line and the unit used in connection with a selector will be indicated.



   Shaft 902 is continuous for line equipment units and selector equipment. At each of the line equipment it carries a cam 905 and at each of the selector equipment it carries a similar cam shown in FIG. 15 in 1523. The shaft 902 and its cams associated with the two pieces of equipment are in constant rotation and the lifts of the cams 905 and 1523 are in alignment. This alignment is important since the operating arm or the inner frame of the line equipment unit called by the selector equipment must rise in accordance with the operating arm or the inner frame. selector equipment.

   When the contact fingers 989 and 992 of the called line equipment unit of fig. 5 meet their respective selector multiple bands 204 and 404 of fig. 6, the contact arms 1535 and 1536 of fig. 15 must at the same time be engaged with their respective response control contacts 1520 and 1521 which are wired in series with the selector multiple contact strip 204, a closing contact 1573 of the latch relay 1508, a coil of relay 1509 and the selector multiple contact strip 404.

  <Desc / Clms Page number 49>

 



   The relay 1510 of fig. 15 and its associated bar 1523 are identical to the call relay 501 of FIG. 5 and its associated bar 1306. All the ratchet functions of relay 501 are therefore performed by relay 1510 on the selector mechanism. The ratchet bar assembly, mainly comprising the mount 918, the bar 921 and the pawls 924 and 925 of FIG. 5, is reproduced by 1527, 1529, 1531 and 1532 in fig. 15.

   The rack 933 of fig. 5 is reproduced by 1530 of fig. 15. The switch strip 958 of fig. 5 is reproduced by 1539 of fig. 15. The contact finger 989 of FIG. 5 is represented by the contact finger 1536 of FIG. 15. The situation of the contact finger 992 of FIG. 5 is reproduced by the contact finger 1536, but this contact finger has the same length as the contact finger 1535.The contact finger 1537 is in the situation of the contact finger 994 and its length is also that of the contact finger 1535.The contact fingers 1535 and 1536 are bonded together instead of being wired to the switch strips like the contact fingers of the line equipment units shown in FIG. 5.



   The relay 1512 and its bar 1533 of the selector equipment of fig. 15 actuate the contact and lift clicks 1531 and 1532 as does the hold relay 502 of the line equipment unit of FIG. 5. However, relay 1512 does not perform the hold function. When relay 1512 operates, rack 1530 returns to normal due to lifting of pawl 1531 and 1532 and is accompanied by the inner frame of the selector equipment.



   The response control contacts 1520 and 1521 are of the same general type and construction as those of the multiple of the selector circuit shown in Figs. 2,3 and 4 except that a space appears between them and that wiring terminals are necessary on each of them.

  <Desc / Clms Page number 50>

 



   They are placed flush with the selector multiple strip 204 of their respective selector circuits and in vertical alignment with the contact arms 1535 and 1536 of their respective selector equipment.



   Immediately above the level of the upper response control contacts 1520 and 1521 and in alignment with the contact finger 1537, a contact tab 1522 is installed as part of a circuit which indicates that a selector and a switch. answering line have not established a connection to the calling line. The operation of this circuit will be explained later.



   The relay 504 of fig. 5 and relay 1510 of fig.



  15 having operated simultaneously, their associated respective contact fingers move together upward. As contact fingers 989 and 992 meet multiple bands 204 and 404 of the selector circuit on which the calling line is on hold and by which the answering line has been activated, the contact fingers 1535 and 1536 of FIG. 15 are engaged with the response control contacts 1520 and 1521 of this selector circuit.



   The circuit is then established in fig. 5 and 15 from earth through relay winding 502, break contacts 587, brush 965, switch strip 956, contact finger 992, selector circuit multiple strip 404- , a winding of the relay 1509, a latched closure contact 1573 of the relay 1508, the response control contact 1521, the contact arms 1536 and 1535, the response control contact 1520, the band 204 of multiple of selector circuit, contact finger 989, switch bar 953, bar 962, break contact 589, break contact 591 on relay 501, winding of latch relay 502 and to the battery, which brings the relay 1509 of FIG.



  15 to operate and release the locked contact from re-:

  <Desc / Clms Page number 51>

 leaves 1508 and also causes relay 502 to operate and latch from earth through one of its coils, through contacts 588, wiper 966, strip 957, wiper 993, selector multiple 405 to the battery to the closing contact 1502. When relay 502 was actuated, its bar 928 triggered all the mechanical locking functions of its associated line equipment unit and caused rack 933 to drop down to the normal. Releasing relay 1508 opened contacts 1579 to release relay 1510 so that cam 1523 no longer actuates arm 1529.



   When relay 504 has been actuated, earth on one; of its windings has been connected by its closing contacts 575 to a break contact 586 on the relay 502 and to the battery, so that the relay 502 keeps the relay 504 activated until the relay 502 gets excited.



   When the calling line established the connection with the selector circuit, the battery from the closed contact 1581 on the relay 1503 was established on the selector circuit multiple band 405, by the contact finger 993 of calling line equipment unit, switch strip 957, sweeper 966, close contact 588, and calling line timing relay coil 502 to ground. This circuit is now used to keep the calling line in engagement with the selector circuit.

   When the responding line contact fingers encountered the selector circuit multiple contacts and were locked in place, the responding line unit contact finger 993 also encountered the contact multiple strip 405 on which the circuit described above is located, so that the battery through the closing contact 1581, the relay 1503, and the selector multiple band 405 to the relays 502 of calling lines also maintains the relay 504 of the calling line in on-pass operation

  <Desc / Clms Page number 52>

 sant by the contact finger 993 of the calling line, the switch strip 957, the brush 966 towards the iron contact, closing 575 of its relay 504 and a winding of this relay towards the earth,

   which keeps the answering line equipment engaged until the calling subscriber disconnects.



   When the answer relay 504 was energized, it closed a circuit from the telephone 510 associated with its line equipment unit to the ringing control relay 505, on whose contacts the talk circuit is now open to the capacitors. 508, 509 and the contact arms 987 and 988 which now engage the selector circuit multiple bands 202 and 203 through which the calling telephone is located.



   When the latch relay 502 operates, the closing contacts 580 place a ground on the break contact 59 of the bell control relay 505. Connecting this ground provides a path for the bell generator 515 through the bell. Bell switch 516, Bell resistor lamp 517, Terminals 518, Bell control relay 505 coil, R-relay 505 break contact 558, Relay 504 closing contact 570, the terminals 550 of IDF, the terminals 511 of MDF, the line, the bell, of the telephone, the telephone capacitor with line return, the terminals of MDF, the terminals of IDF,

   close contact 572 of relay 504 to ground made on break contact 559 of relay 505 by operation of relay 502. AC current flowing through this path causes the telephone ringing 510 to ring.



   The ringing periods are controlled by the switch 516 which alternately connects the ringing circuit by the ringing generator from, from the battery and by a direct conductor.

  <Desc / Clms Page number 53>

 ringing, an alternating current is superimposed on a direct current which passes through the ring resistor lamp 517 and a coil of the relay 505 to the called telephone.



   Telephone capacitor 510 only allows the AC component of ringing current to flow into the ring. The bell control relay 505 is of the type in common use in telephony designed not to operate on alternating current and to operate on direct current. The battery in series with generator 515 has no effect as long as there are only rings across the line, but when lifting a receiver on the line, a trip is supplied for direct current through relay 505 which operates and is locked by its other winding and the closing contact 580 of the hold relay 502, keeping the relay 505 actuated until the hold relay 502 is de-energized and remove the ringing earth.



   Capacitor 560 passes a sufficient amount of ringing current through the calling line for it to be heard by the calling subscriber, which informs the calling subscriber that the line he called is ringing.



   With the operation of relay 505 the conversation pair is extended by closing contacts 558 and 559 of capacitors 508 and 509, closing contacts 582 and 584 of latching relay 502, brushes 960 and 961, switch bands 951 and 952, the contact fingers 987 and 988 to which it connects to the selector circuit multiple bands 202 and 203 on which the calling line is located.



   A pair of wires run from the talk circuit to the windings of line relay 501 to supply the talker battery at 510 for the telephone. Caller relay 501 is actuated in conjunction with the operation of control relay 505. ringtone and operations

  <Desc / Clms Page number 54>

 rack control bar of its bar 1306 have already been performed by the rack control bar 906 of relay 504.



   De-energizing and releasing relay 504 'immediately after energizing relay 504 at contacts 579 opens conductor 530 to provide the busy signal in the event that the answering line is requested by other lines. appellants. Therefore an open circuit on a conductor such as conductor 530 designates a busy line for the selector or recorder.



   Close contact 576 on relay 504 controls a warning circuit which operates an audible signal and locks the line equipment unit in place when, in its responding operation, it does not connect to the selector circuit. by which she was called.



  This warning circuit runs from the battery on the latch relay winding 502, through the close contact 576 of the relay 504, and a make contact in a group 982 of the trip mechanism, the relay winding of. warning 506 and down to earth. A close contact of relay 506 completes a battery circuit through the warning bell and earth, which causes the bell to operate.



   When the above circuit has been completed by latch relay 502, this relay has performed its latch function previously described. As the warning circuit can only be completed by the trip mechanism when the line equipment unit has operated to its limit in front of the selector multiple and pin 945 has engaged with the bump of the spring 948, it will be obvious to the personnel which line equipment has not fulfilled its responding function.

   The line equipment unit is brought back to normal by pushing its organ by hand

  <Desc / Clms Page number 55>

 slide 930 out of a notch 935 of the L-shaped part 934 shown in FIG. 5 and let the line equipment unit return to normal, where pin 946 meets trigger mechanism spring 947, returns contact group 982 to normal, and opens circuit. earth on relay 506, causing the bell to stop ringing.



   Electrical and mechanical details of the called line selector unit.



   The essential mechanical details of the selector unit are shown in figs. 16,17,18,19 'and 20. As, however, many mechanical operations of the unit depend on the state of its electrical characteristics, it has been felt that a clearer understanding will be obtained by the description made from of the selector equipment operating diagram shown in fig. 15, to which we will now refer.



   When a calling line found that a selector was free, the contact fingers of the line equipment unit were locked in engagement with the multiple contact bands 202, 203, 204, 404, 405 and 406 of this selector circuit. When this connection was established with the calling telephone, the multiple contact strips 202 and 203 of the selector circuit participated in the closure of a battery path, by a winding of relay 1501, the telephone , return to the other winding of relay 1501 and to earth, which energized relay 1501 and made it operate. The dial of the calling telephone is in series with the circuit which operated relay 1501 and normally keeps the circuit closed.

   When, however, the dial is actuated, it causes the production of a succession of breaks in the circuit between relay 1501 and the telephone, ooncor-

  <Desc / Clms Page number 56>

 dance with the value formed on the dial. Consequently, when the dial operation takes place, the relay 1501 de-energizes and energizes alternately, which introduces the dial pulses into the selector circuit.



   The battery supply relay 1501 carries a make contact and a break contact. Close contact 1561 closes the battery by winding a slow release relay 1502 which, when actuated, releases too slowly to be de-energized when a dial pulse break causes it to open. momentarily the close contact of relay 1501, so that the close contact 1563 of relay 1502 remains closed while the dial operating operations are taking place. Close contact 1563 of relay 1502 closes a circuit from the battery to the coil of relay 1503 and to ground, which operates that relay and keeps it energized as long as the loop is extended to relay 1501.



   Relay 1503 performs many monitoring functions in the selector circuit. When normal, break contacts 1582 provide ground to selector multiple band 406 whereby a calling line equipment unit finds a free selector. Close contact 1581 supplies battery to selector multiple band 405 which is part of the circuit keeping calling line equipment locked to the free selector circuit it has found. Close contact 1588 also freezes the circuit. battery on a closing contact of relay 1508, which at this time is not actuated.

   This closing contact of relay 1503 also places the battery on the windings of relays 1509 and 1514 'and by the latter on contact tab 15.22.



  * It also places the battery on a closing contact of relay 1513 which operates when a line is found busy and on closing contact 1570 of relay 1509

  <Desc / Clms Page number 57>

 for a subsequent extension in relay 1512.



   The closing contact 1581 of the relay 1503 places the battery on a closing contact controlled by the bar 1533 associated with the relay 1512, so that when the relay 1512 is once actuated, it is kept actuated while the calling line is on. in connection. This closing contact on relay 1503 also places the battery on a closing contact on relay 1580.



     Another closing contact 1583 of relay 1503 transmits the dial operation sound to the calling subscriber by connecting the dial operation sound on conductor 1567 to the earth side of the conversation pair, immediately in front of relay 1501 and through capacitor 1590. An alternate make contact 1587 on relay 1503 establishes busy sound on the calling line when needed.

   The busy sound on conductor 1566 by a closing contact 1591 of the busy test relay 1513 which is then energized is carried by the closed closing contact 1587 of the relay 1503 through the capacitor 1590 and to the earth side of the conversation pair on the same conductor as that used by the dial maneuver sound. Operation of relay 1513 is controlled by a break contact 1572 of relay 1580.



   A break contact 1586 of relay 1503 operates when relay 1503 de-energizes upon completion of a call and controls the called line selector equipment return to normal.



   An additional make contact on relay 1503 is in series with a break contact of relay 1001 and the windings of relays 1504 and 1505 so that when relay 1501 drops out on the first break of the dial pulse circuit, the battery is momentarily supplied by the closed break contact 1562 of the relay 1501, the closed contact 1584 of the relay 1503 and the winding of the relay 1504, the winding of the relay.

  <Desc / Clms Page number 58>

 left 1505 and to earth, which causes relays 1504 and 1505 to operate for the duration of the break, after which relays 1501, 1504 and 1505 return to their initial state.



   When relay 1504 operates, a weight spring forming part of its contact is caused to vibrate in a raised position and does not normally come to rest on the other contact spring until sufficient time has elapsed to that another impulse action has taken place; therefore if another pulse operation occurs a fraction of a second after the first, the weight spring is lifted again and returns to engagement with the other contact only when any series of pulses have been completed. The contact of relay 150 is closed whenever this relay is energized or de-energized for a period of time somewhat longer than the interval of a dial pulse.



   When relay 1501 first operates by connecting the calling line, its break contact 1562 operates before the contacts of relay 1503, so relays 1504 are not energized until sending. dial pulses occur. Relay 1504 contact has earth placed on it and extending to a close contact of relay 1503 which operates as a result of relay 1501 operation; Therefore this circuit extends through the winding of relay 1506 to the battery and actuates this relay. Relay 1506 remains actuated until the first pulse operation occurs, at which time relay 1504 is energized. and its contact opens, which drops relay 1506.



  The following mechanical operations take place as a result of these circuit changes.



   The excitation of relay 1506 has attracted its frame 1631 which is hinged on pivot 1632, this pushes pawl 1630 into engagement with the first tooth of the control bar

  <Desc / Clms Page number 59>

 1625 and puts a tension on the spring 1633. The spring 1636 is put under tension to push the end. from pawl 1630 to digit control bar 1625.



  During the pulse interval of a series of dial pulses, the contact on relay 1504 is open so that with the first pulse relay 1506 is de-energized and its armature 1631 and the associated pawl drop. in their normal positions, the pawl 1630 pulling the digit control bar 1625 with it against the tension of the spring 1629. When the second tooth of the digit control bar passes in front of a slight protrusion from the retaining pawl 1627 this protrusion falls into position behind the second tooth of the bar 1625, thereby 'retaining this bar in its raised position.'
When the pulse of the dial caused relay 1506 to de-energize, it energized relays 1504 and 1505 at the same time.

   The relay 1505, by being excited, switches a bar 1610 towards the racks 1640, 1641 and 1642 and 1643 and its attached pawls 1611, 1612, 1613 and 1614 are moved: consequently in the same direction. Hatch marks on the finger control bar 1625 indicate recesses into which the pawls 1611 to 1614 fall when it is their turn to activate their respective racks 1640 to 1643. The four pawls 1611 to 1614 move. together, but as a result of the offset of the recesses, only one at a time engages with a rack.

   In fact, as shown in fig. 16, there is only a recess which controls the engagement of the pawls 1611 to 1614 and for the operating diagram of FIG. 15 it is necessary to provide four of these recesses to show the operations in a plane.



   As the digit control bar 1625 moves with the outward movement of the pawls 1611 to 1614 in the direction of the racks, the pawl 1611 will have reached the end of its outward movement at the same time. when it falls into the recess

  <Desc / Clms Page number 60>

 of the bar 1625 which has been brought into position below it, which causes its tooth to engage the first tooth of the rack 1640.



   When bar 1610 has switched, voltage has been established in spring 1617. When the period of the dial pulses is completed and relay 1501 is energized again, relays 1504 and 1505 are de-energized so that the voltage spring on the bar 1610 brings this bar back to the normal position and consequently brings back the pawls 1611 to 1614. The pawl 1611 being the only one engaged with a rack causes the rack 1640 to move with the pawl turning. This movement of the Rack 1640 places tension on spring 1673 and causes the tooth of retaining pawl 1619 to engage the third tooth of rack 1640, which maintains the rack in its actuated position.



   When a dial pulse was completed and was not followed by additional pulses developed by the same dial operation operation, the contact on relay 504 closed and relay 1506 became energized again, this which causes pawl 1630 to engage the second tooth of the digit 1625 control bar.



   When the rack 1640 was moved by the action of an impulse, an elevation of its upper surface was moved away from below an elevation 1650 of a group of monitoring contacts and brought under an elevation. 1650 of the model 1 contact, which closed this contact.



   Referring to fig. 16, 18 and 19, it will be noted that the construction of each group of contacts is the same although there is a variation in the number of contacts of the vertical rows of the group and in the length of the groups. The thousands contact group associated with the 1640 rack is the longest and the units contact group associated with the 1643 rack is the shortest.

  <Desc / Clms Page number 61>

 



  The relative length of the contact groups can be seen in fig. 16. Each vertical row of contacts contains the lower retaining spring 1651 and the upper retaining spring 1654 which are energized to hold the notched part 1655 in position. The ends of these parts 1655 are one-dimensionally. slightly smaller than the general cross section elsewhere and fit into stamped holes in the retaining springs 1651 and 1654. Parts 1655 are made of solid material and provided with notches to support and lift the spring ends of the springs. contact 1656 which are individually clean to the contact.

   When deemed necessary to clean or adjust the contact springs in any vertical row, parts 1655 may be lifted out of the retainers 1651 and 1654 to make the contact springs accessible for adjustment. contact contacts 1657 of each horizontal row of contacts, except the monitoring contacts at the end of each group, are common to the entire horizontal row and are stamped in a single piece as shown in fig. 20 which is a plan view of a typical 1657 stamped piece.

   The support bands 1660 are also made of insulating material and the terminal end of the contacts is held in place by two screws 1661 provided with a sleeve of insulating material and engaged in threaded holes of the base part 1601; the machine screws and their associated sleeves are shown in fig. 16 and its similar to those shown at 301 and 302 in FIG. 4.



   We will now come back to the operating plan of the. fig. 15 where. two exploration contact tabs 418 and 419 have been shown in the upper right-hand corner. A conductor extends from the contact tab 1518 towards the main conductor 1657 of the contacts associated with the contact. rack

  <Desc / Clms Page number 62>

 1640. The cog 1640 activates the contact group of thousands; the rack 1641 activates the contact group of hundreds; the rack 1642 activates the group of tens contacts and the rack 1643 activates the group of contacts of the units.

   The numbers 1 to 0 near the contacts of the rack 1640 indicate which group of a hundred lines this contact feeds when it is formed. The figures adjacent to the contacts of the terminal vertical rows and across the upper horizontal row indicate the group of one hundred lines which each contact could supply power when closed. Similar designations are used in the tens and ones groups. In the tens group the numbers next to the contacts indicate which group of ten lines each contact will feed.



  In the group of units, the figure indicates which unit of one hundred lines the adjacent contact could supply.



   It should be understood, of course, that when the invention is employed for line selection in a 10,000 line system, each unit to be selected requires a four-digit call number and hence the call pulse. The dial which was introduced earlier directed the selection to the group of rows of thousands N 1. It will be assumed that the number 1 is formed on the dial three more times, the full call number being 1111.



  During the next maneuver of the dial, the relay 1501 is de-energized; the relays 1504 and 1505 are energized and the relay 1506 is de-energized; the digit control bar 1625 advances and brings a recess into position under the pawl 1612 which at the same time moves towards the rack 1641. The pawl 1611 is lifted away from the rack 1640 again once as a result of the displacement of its associated recess in the digit control bar 1625. Upon completion of the breaking of the pulses the relays 1504 and 1505 are de-energized again and the relays 1501 and 1506 are energized again.

  <Desc / Clms Page number 63>

 



  The pawl 1612 attracts the rack 1641 on an advance and the elevation on the upper face disengages from the monitoring contact of the group 1576 and moves into position on the row 11 to 01 of hundreds contacts which closes the contacts in this row. When forming the other two digits on the dial, the operations of relays 1501, 1504, 1505 and 1506 are identical to the previous operation, except that the recesses of. The digit control bar 1625 first allowed the pawl 1613 to operate and bring the rack 1642 into position with its elevation on the contact designated by 1 in the tens group and closing that contact.

   The following operation of the oadran maneuver allowed the pawl 1614 only to connect to its starter 1643 and to bring the heightening of the rack 1643 on row 11 to 01 of the unit contacts, forcing them to close. . The call number 1111 has then been formed or stored in the selector equipment and is ready to be started in the response relay 504 of the line equipment unit of FIG. 5.



   When the first operation of maneuvering the dial or operation of the thousands closed contact 1 of the row of contacts resting on the rack 1640, it connected the common conductor placed across the groups of the thousands of contacts, this conductor s' extending to a common conductor which represents the first mile in the group of hundreds of contacts associated with rack 1641 which had closed the first row of contacts in concordance with the second operation of the dial operation or operation of the oentaines. has now established continuity between the scan contact pin 1518, the common conductor of the thousands contact group, the common conductor representing the number 1 thousand in the hundreds of contacts group, and the hundreds group denoted by 11 .

   In the 10,000 line system there will be 100 groups of 100 lines. Each of these groups carries one of the

  <Desc / Clms Page number 64>

 designations indicated in the group of hundreds of contacts. From each contact of the group of hundreds leaves a conductor which is common to the windings of the 100 response relays 504 ', fig. 5, of the 100 units of line equipment in this group. For example, contact 11 has a conductor extending to 100 units of line equipment whose call number begins with the two digits one-one.



  In fig. 5, conductor 532 represents the wire extending from contact one to one of the group of hundreds of contacts of FIG. 15 and conductor 533 represents the common conductor extending to the other 99 relays 504 'of the hundreds one-on group.



   When the rack 1641 of fig. 15 has closed the vertical row of contacts 11 to 01, only contact 11 has been chosen. The remainder of the contacts in the vertical row, though closed in the hundreds group, have their associated common conductors kept open in the thousands group of contacts.



   A circuit path has now been established and extends from scan contact 1518 of FIG. 15 through the thousands and hundreds recorder from the selector to lead 532 of FIG. 5, through contacts such as contacts 574 and 585 to the 100 relay windings 504 'of the response lines of Fig. 5, as a result of the dial-forming operations of the thousands and hundreds.



  We will now consider the exploration contact 1519 of FIG. 15 and the circuit path established by the tens and ones dial training operations will be determined. A conductor extends from scan contact 1519 and establishes continuity from contacts through a resistor R and the winding of relay 1508, contacts 1594 of relay 1507 absorbing pulses to a common conductor 1657 across them. contacts 1 to 9 of the group associated with the rack 1642, in which the contact 1 is closed so that its common conductor in the group of contacts of the units associated with the rack 1643 is

  <Desc / Clms Page number 65>

 connection.

   In the units contact group, the vertical row 11 to 01 to 11 has its contacts closed, but continuity from the scan contacts 1509 is established only through contact 11.



   In a 10,000 line system there will be 100 call numbers ending with the digits un-n. It will be assumed that a conductor extends from the one-to-one contact in the contact units group and is common to the 504 response relays of all line equipment ending in the one-one. A typical representation of A similar connection is shown in fig. 5 where the conductor 530 extends through the breaking contacts 590 to the coil of the relay 504 and then through the closing contacts 579 to earth + The conductor 531 extends to others,

   line equipment units whose call number ends with the digits one-to-one and in which similar connections to the respective relays 504 are established.



   Circuit paths have now been completed in fig. 15 from scan contacts 1518 and 1519 through the answering line model selection network of recorders in the selector. The first two operations of maneuvering the dial to call the number 1111 established continuity towards the first hundred of the first thousand relays 504 'of the responding line. The following two operations of maneuvering the dial established continuity towards the first unit of the first ten lines in all the hundred lines. In the group of one hundred lines identified by one-one, there is only one unit which has the two circuits to the response relays 504 and 504 'prepared upon completion of dial training of call number 1111, and it is the one-in-unit.



   When the earth is connected to the scanning contact 1518 in fig. 15, the following circuit is complete: the earthed friction contact 1550, the scanning contact 1518, the common conductor 1657 of the thousands contact group ,

  <Desc / Clms Page number 66>

 the thousand contact 1 activated, to the common conductor 1657 of the hundreds groups, the hundred contact activated marked 11, to the conductor 532 of the thousands and hundreds assigned to the group eleven hundred, contacts such as contacts 574 and 585 to the windings of the relays 504 'in this group of hundreds to the battery.

   All the relays 504 'in this group of hundreds are energized and at their contacts 579 they connect the earth to the winding of the associated relays 504 to prepare their operating circuits of which only one is complete in accordance with the recording of the tens and units.



   When the battery is connected to the scanning contact 1519 of fig. 15, the following circuit is complete to energize the relay 1508 and a single relay 504 in series. The battery flows from the wiper 1551 through the contact 1519 to a resistor R, the winding of the relay 1508, the contact 1594 on the pulse absorbing relay 1507, the common conductor of the tens contact group, the contact designated by 1 in the tens group and its common conductor associated in the group of contacts of the units, the contact 11 of the group of the contacts of the units, a conductor of the tens of the units not shown in fig.5, the common conductor 531 (fig.5), the conductor 530 of the.

   tens and units of the line equipment unit 1111, the break contacts 590 on the line relay 501, the winding of the relay 504 of the responding line, the closing contacts 579 of the relay 504 ' associated response, down to earth. Although all relays 504 'with the same designations of thousands and hundreds in these eleven hundred groups can be energized by the common thousands and hundreds conductor, such as 533, only one relay 504 is energized because a single common conductor of tens and units, such as 530 is connected in this group to the battery by the exploration slider '

  <Desc / Clms Page number 67>

 1551. Consequently the relay 504 associated with the line equipment of the line registered in the selector is the only relay 504 which is energized.



   Upon completion of the circuits described above, the responding relay 504, of Fig. 5 has been energized and the relay 1508 of Fig. 15 has also been energized. The functions of these relays have been described previously and will not be repeated here.



   The battery and the earth which are used to activate the lines called by the exploration contacts are supplied by a part of the apparatus common to the system which is activated when the formation operation of the last. The digit of the call number is started on the dial. This unit is called the exploration arm. In operation, it wears contact fingers across the scan contacts 1818 and 1519. The scan arm is typically a simplified form of the line equipment unit, dirtily bearing two contact fingers, two switch bands, two brushes and a trigger mechanism.

   All details of rack advance and retainer have been eliminated. The exploration arm is lifted by a pressure bar extending from the lower end of its operating arm, between a continuously rotating wheel. and a freewheel at which pressure is applied when a lifting action is required.



   The contact group 1578 associated with the contact group of. units contains a 1597 closing contact on which the battery is placed. It can be seen that with the first displacement of the rack 1643 during the establishment of the value formed on the dial of a fourth digit, the contacts of the group 1578 will close as a result of the displacement of the elevation on the rack 1643 which had kept contacts open. The battery then flows from contacts 1597 through a conductor common to all circuits.

  <Desc / Clms Page number 68>

 selectors to a break contact 1556 of the scanning arm trigger mechanism. This trigger mechanism consists mainly of locking springs 1553 and 1554.

   From contact 1556, the battery flows through a conductor extending to the winding of relay 1511 through this conductor and to earth, which energizes relay 1511 and causes its associated bar 1540 to press idler 1541 against a slightly flexible shaft 1542 which in turn is pressed against the constantly rotating impeller 1543, causing the shaft 1542 to move upward. Tree 1542 is attached to a cider similar to that of the line equipment unit shown primarily in fig. 4.



   A pair of scan contacts 1518 and 1519 are required for each selector circuit in the system.



  These contacts are similar in construction and assembly to those shown in L'il- ,. 2,3 and 4-. Only one vertical row of each of the contacts is required.



  These two rows are in horizontal alignment with the two contact fingers of the exploration arm. If other exploration arms are to be provided for use as a back-up or as an alternative, it will be necessary to connect multiple exploration contacts 1518 and 1519 accordingly.



   When a scan arm reaches its operating limit after passing through scan contacts 1518 and 1519 of each selector circuit, the trigger mechanism returns it to its normal position and if its operation is still required by a closed contact 1578 in any selector circuit, it causes it to restart its operation.



  Pin 1545 on reaching the bump of spring 1554 pushes this spring into engagement with a step of spring 1553, which locks these two springs together and opens the

  <Desc / Clms Page number 69>

 contact 1556 by de-energizing the electromagnet 1511 which allows the pin 1540 to relieve its pressure on the wheel 1541 and the bar 1542. As a result of the elimination of this pressure, the exploration arm falls back until pin 1555 meets the tip of spring 1554 which releases spring 1554, which returns to normal and closes contact 1556.



   The battery is on the sweeper 1551 of the exploration arm and the earth is on the 1550 sweeper. This battery and earth are carried to the contact fingers by the. switch strips 1546 and 1547. When the scanning fingers meet the scanning contacts 1518 and 1519 of the various selector circuits of the system, if the operation of the dial has been completed in any of the selector circuits , this applies battery and ground through the registered selector pattern to energize the responding relay 504 of the desired line, as described previously.



   While a connection is maintained between two telephones or other units employing this system, the called line patterns established in the thousands, hundreds, tens and units contact groups remain in the operated position until. what the calling telephone or other calling unit disconnects; therefore contact 1576 will keep the scan arm in operation while any connection is maintained in the system.



   In the 10,000-line system, the contacts of the hundreds and the contacts of the units of the different selector circuits are linked together in multiple. The hundred conductors required for the group of units and the hundred conductors required by the group of hundreds constitute the total number of conductors required between the line equipments and selector equipments and in different selector equipments for the selection of the selector equipments. lines called.

  <Desc / Clms Page number 70>

 



   The inventors believe that after the foregoing description of the operations of the selector circuits for call number 1111, the operations for any other call number will be well understood. If the call number formed on the dial in the selector circuit had been 0000, the raising of each of the four racks 1640, 1641, 1642 and 1643 of fig. 15 would have carried out ten advancements and would thus have closed the right vertical row of contacts in each group and set a pattern in the selector circuit network to the line 0000 line equipment unit.



   In the unit contact group associated with the 1643 rack, a horizontal row of contacts, not part of the called number pattern contacts, extends across a vertex of this group, as shown in fig. 5 ' This row of contacts, along with relay 1507 prevents premature selection and the resulting bad numbers by ensuring that the circuit coming from scan contact 1519 remains open while rack 1643 is moved to. its final position.

   If the call number of a desired line ends for example with the digits 50 it will be necessary for the raised section of the rack 1643 to move, closing them momentarily under the contacts of the other nine vertical rows to reach the position. end in row 0. Momentarily and in turn, all line equipment units with call numbers containing a 5 as the tens designation will be connected. This cannot however cause any disturbance if the connections are not supplied and therefore the circuit from the scanning contact 1519 must be kept open until the rack 1643 arrives in its final position.

   The earth on the springs 1656 of the upper row of contacts in a group of units completes a circuit for the relay 1507 so that during each advance of the rack 1643, the relay 1507 is alternating, / It

  <Desc / Clms Page number 71>

 strongly excited and de-energized in accordance with the number of vertical rows in front of which the raised section of the rack 1643 must pass to reach its final position.

   Operation of relay 1507 causes its weight contact spring to lift and vibrate in a raised position for a period of time somewhat longer than the period of a dial pulse; therefore if a series of pulses is introduced into the relay 1507, the vibrating contact spring remains lifted until the series of pulses has been completed, which keeps the connections open through When the rack 1643 arrives in its final position, the circuit by the relay 1507 is closed for the duration of the connection and as the vibration of the weight contact is reduced it also settles in its closed position despite that relay 1507 is energized.

   A subsequent exploration operation then feeds only the desired line.



     Occupancy test circuit.



   A tap on the conductor between resistor R and the winding of relay 1508 extends through rear contacts 1572 of relay 1580, through a winding of relay 1513, contact 1593 absorbing the pulses, of relay 1507 ' . the closing contacts 1596 of the contact group 1578 to earth. This circuit is closed only when a fourth digit dial training operation has moved the elevation of rack 1643 allowing contact group 1578 to operate and contacts 1593 of relay 1507 are closed.

   When the scan rubbers 1550 and 1551 meet the scan contacts 1518 and 1519 of a selector circuit on which a full dial maneuver is placed, if the line is not occupied the The battery finds a path from scan contact 1519 through the windings of line relay responding 504 from the desired line to ground at contacts 579, as previously noted.

   We will find that the, 7

  <Desc / Clms Page number 72>

 The above circuit by the winding of relay 1513 is in parallel with the circuit by the response line relays 504 between battery and earth. The combined resistance of relay 1508 of fig. 15 and a line relay responding 504 of FIG.

   5, which are in series when actuated, is much less than the resistance of the operating winding of the relay 1513, so that if the battery is applied to the scan contact 1519 and if a continuous is found through a 504- responding relay, the 1513, being marginal, cannot get enough current to operate. When a called line is busy, one of the conductors 530 and 532 in fig . 5 or both, are open in accordance with the state of relays 501, 502 and 504 in the connection and when the battery is applied to the scanning contact 1519, no current can flow into the connection through the relay 1508,

   therefore relay 1513 can obtain sufficient current to operate. When relay 1513 operates, the earth on one of its windings is extended by the closing contacts 1592, the closing contact 1588, previously closed, of the relay 1503 to the battery, which keeps relay 1513 in an actuated position while the calling line is connected. In addition, closing contact 1591 of relay 1513 connects the busy sound coming from conductor 1566, through the Close contact 1587 of relay 1503, capacitor 1590 to the post-facing side of the grounded winding of relay 1501.

   The busy sound is thus routed to the calling telephone and the calling subscriber recognizing the busy sound, disconnect.
The relay 1580 of fig. 15 is provided to keep the busy sound signal out of an established call. When relay 1508 operates, a called line is also activated so that the device-

  <Desc / Clms Page number 73>

 The occupancy test age is no longer required. When the relay 1508 operates the battery by the closing contacts 1588 and 1574 is connected to the earth by the winding of the relay 1580, which energizes this relay which operates and is locked by its closing contact on the battery. supplied by the closing contact 1502 of the relay 1503 which had been activated previously by the calling line.

   Operation of relay 1580 opens break contact 1572 in the busy test circuit to the coil of relay 1513, preventing the busy test from operating for the duration of the call. ,,
Sequence of calls control circuit
During a busy hour, two or more outgoing calls made simultaneously would result in two or more line equipment of FIG. 5 would link to the same free selector circuit if the circuits of fig. 5.

   For clarity in describing the call and answer operations of relay 501, call succession control details have been deleted in FIG. 5. Refer to fig. 7 which indicates relays 501 and 502, part of contact groups 982 and 938, of two adjacent line equipment units, wired for these ordering details. Additional contacts 541, 542 and 543 are installed in each contact group 938, additional contacts 544, 545 and 546 are installed on each relay 502, and the additional break contact 539 is added to each relay 501. will consider in fig 7 that the contacts 938 and their associated relay 501 on the right have first chosen in the input operation.

   In other words the line equipment unit attached to this relay 501 and contacts 938 will have its snap-in characteristics activated ahead of a line equipment to the left if a choice is required. Throughout the system, if two or more

  <Desc / Clms Page number 74>

 lines call at the same time, the right unit will be preferred if it is assumed that the wiring in fig. 7 is maintained throughout the system.



   It will be assumed that the two relays 501 of fig. 7 have a call short circuit established across them at the same time. The complete call circuit of each is shown in fig. 5 between the telephone 510 and the windings of the relay 501 and the battery supply relay 501 is modified in accordance with fig. 7. The two relays 501 receive current through their windings simultaneously, but the right-hand relay 501 alone remains actuated since its breaking contact 539 cuts off the arrival of the battery to winding 501 on the left,

   which forces the left relay 501 to drop. The right relay 501 being energized causes the start of the rack operations of its line equipment unit which raises its pin 937 which is connected to the rack 933 and brings its group of contacts 938 to operate and to close and open certain contacts included in the group. With the closing of contacts 541 of contact group 938 of the right line equipment unit, the left relay 501 now has the battery established across its winding and this relay too can do. start the rack operations of its line equipment unit.

   If all relays 501 located to the right of a relay 501 used in an incoming call operation are unactivated or fully actuated the relay 501 used in the call in operation will not be delayed in the start of the call. its rack operations.



   The rupture contacts 539 of the relay 501 of the system are wired in series with the battery on the right contact; therefore when any of the relays 501 is operating, all relays 501 to its left will not receive the operating battery until the right relay 501 has started its build operations.

  <Desc / Clms Page number 75>

 mesh; at this time its contacts 541 in the group of contacts 938 operate and restore the battery to the same circuit in series.

   The initial drive circuit of relay 501 extends from the battery through break contacts 542, 545, and 982 through the relay coil and through the calling mouth. Contacts 543 close before contacts 542 open to maintain the battery on relay 501 while 933 is out of normal. Contacts 544 are provided to maintain the continuity of the starting circuits when the line is called. Contacts 545 and 546 are provided to maintain the starting circuit. battery on the winding of relay 501 when this line is a called line so that the initiation of a call by a line with less preferential choice does not momentarily interrupt the supply of battery to the called line .



  With this circuit arrangement, the first choice relay 501 opens at contacts 539 and prevents any further relays.
501 to fully energize and operate its rack gear when initiating a call until the line switch of first choice has made at least one advance from normal; at this time the contacts 541 close to allow another relay 501 to energize and start its line switch.

   A number of line switches can simultaneously search for a free selector, but since they are spaced at least one advance apart, they do not simultaneously encounter the same fixed relay contact of a free selector, preventing double tap of the same. selector free.As soon as relay 502 is energized as a result of what the line is calling or being called, contacts 544 close to maintain starter circuit continuity while contacts 546 maintain battery application to the line. winding of relay 501 until communication is released.

  <Desc / Clms Page number 76>

 



   Grouping circuit of responding lines
When two or more line equipment must answer the same call number, as in the case of a group of trunk lines at a private branch office, it is necessary to modify the dial in fig. 5 of each line unit applied to response relays 504 and 504 'to adapt it to the wiring shown in fig. 8.When battery and ground are established across conductors 532 and 530, relays 504 and 504 'of the straight line or incoming equipment unit will be energized and the latch winding of relay 504 maintains the relay 504 in the energized state for the duration of the communication.

   By locking, the relay 504 opens at the break contacts 574 the circuit to the associated relay 504 'and to its left closing contacts, it connects the conductor 530 to the second relay 504 to the left. At the same time the closing contact 574 of the same relay 504 completes a path to the coil of the left relay 504 'so that if another call is established on conductors 530 and 532, the middle line equipment unit responds by operating its relays 504 and 504 '. By responding to relay 504 in the middle closes conductors 530 and 532 through the third relays or left relays 504 and 504 '. This succession is continued through the number of line equipment units which are included in the group.



   It will be assumed that the three relays 504 shown in FIG. 8 are energized and relay 504 on the left is released first; it then takes its first position across conductors 530 and 532. It will now be assumed that relay 504 at the right end of the group is released. right then takes precedence over left relay 504 by breaking the connection of left relay 504 with conductors 530 and 532.



   Logout.



   Each time a calling party disconnects by hanging up its receiver or otherwise breaks the continuity of the

  <Desc / Clms Page number 77>

 line circuit through the calling telephone or calling unit, all the equipment involved in the communication at that time is brought back to normal. For greater clarity have the ordering details of the return to normal of the equalization units. - line item have been deleted in fig.5 but are shown in fig.23, the dotted part of which includes the equipment shown in fig. 5 and whose operations have been described previously. It can be seen in FIG. 23 that a closing contact is added to the relay calling 501; that two make contacts are added to contact group 938 and that one break contact is added to relay 502.



     When a receiver is lifted by a calling line enough for its associated calling relay 501 to begin rack operations, it is essential that a cycle of calling operations be completed to prevent the equipment from being switched. line remains in an out-of-normal position despite the calling subscriber disconnected, therefore when relay 501 is actuated, it must remain in operation until the contact fingers have found a free junction line, that the restraint relay 502 has operated and that the @ re-link 933 has returned to normal. If a free junction line is not found, the cycle is completed on the contrary by the action of the trigger mechanism .



   We see fig. 23 that when relay 501 is actuated by an inrush short circuit, the battery is extended by one of its windings and one of its closing contacts a group 938 closing count (if it is closed). if rack operations have started and rack 933 and pin 937 have been lifted a break contact of relay 502 to earth, which keeps relay 501 operating until relay 502 either actuated by finding a free trunk line or by the trigger action, those two.

  <Desc / Clms Page number 78>

 cases having been described previously.



   When this disconnection takes place, it is important that the interlock relay 502 remains actuated until the rack 933 has returned to normal. For normal connection, the hold relay 502 remains actuated for the full period. connection once it has operated, allowing rack 933 sufficient time to return to normal before relay 502 de-energizes. However, this is not the case with a premature disconnection and therefore, hold relay 502 can be held in an actuated position until rack 933 returns to normal.



  When the hold relay 502 operates and a ratcheting operation has lifted the @ ratchet 933, the battery by the second make contact of the contact group 938 holds the relay 502 until the ratchet 933 returns to normal and its pin 937 actuates contact group 938 and the battery is off.



   The extra break contact in the hold relay 502 opens the latch circuit for the relay 501, so that when the relay 501 is employed in its response operation, this ground is not effective as the hold relay 502 is excited at the same time.



   It will now be assumed that a communication has been established between two telephones and that the called subscriber was the first to disconnect, thus de-energizing relay 501 by removing the closed circuit which had been maintained across this relay by the telephone. called 510.

   Bell relay 505 and answer relay 504 still remain actuated as they are under the control of the de-hold relay 502 which in turn is kept in operation by the calling line. Referring now to fig. 15 together with fig. 5 it will be assumed that the calling subscriber disconnects. The closed circuit he had maintained, from his

  <Desc / Clms Page number 79>

 phone 510 to the break contact 571 and 573 of the non-actuated relay 504 of its line equipment unit, the closing contacts 582 and 584 of the actuated relay 502 of its line equipment unit of brushes 960 and 961, the switch bands 951 and 952, contact fingers 987 and 988, selector multiple bands 202 and 203, relay windings 1501, battery and ground, is open when the receiver is returned to the switch hook ,

   which de-energizes relay 1501 and causes it to drop.



  When relay 1501 is de-energized, it removes the battery from the coil of relay 1502 which causes this relay to drop by removing the battery from the coil of relay 1503. By releasing the relay 1503 has removed the battery from the band of selector multiple contact 405.This battery had kept in operation the interlocking relay 502 of the calling line equipment unit as well as the interlocking relay 502 of the answering line and its responding relay 504 which all When the relay 502 of the answering line drops its ringing relay 505 to its locking earth removed and consequently it also drops again. With the release of the locking relays 502 on the equipment of the calling and answering lines ,

   all the interior frames of their line equipment units fall back to normal and thus free the respective contact arms.



   In the selector circuit when the relay 1503 drops the battery that was on the windings of the relays 1512 and 1580 is disconnected, so that the pawls 1531 and 1532 of the ratchet bar 1529 of the circuits of Selectors drop back into the engaged position under the upper tooth of rack 1530. The inner frame of the arm operating the selector circuits is returned to normal when relay 1512 has operated.



   When the racks 1640, 1641, 1642 and 1643 were moved during the establishment of the dialed number selector model, the contact groups 1575,1576, 1577 and,

  <Desc / Clms Page number 80>

 1578 were activated and their respective contacts were closed.

   When relay 1503 drops, the battery on a currently closed break contact 1586 of relay 1503 is extended by the windings of relays 1561 and 1560 to earth on closed contacts 1575 to 1578, which energizes the relay 1560 and 1561.The armature of the relay 1560 is attached to the release bar 1672 which engages the retaining pawls 1619 to 1622 by pulling them away from the teeth of their respective racks 1640 to 1643 and lifting up at the same time the pawls 1611 to 1614 out of the teeth of their respective racks 1640 to 1643.

   When the racks 1640 through 1643 are actuated, tension is established in the springs 1670 through 1673 so that when the retaining and operating pawls are disengaged from the racks, the racks drop to their normal position in the racks. - which the elevation at the top of each rack 1640 to 1643 opens the contacts of the groups of contacts 1575 to 1578, which removes the earth of the relays 1560 and 1561 and causes these relays to de-energize, the shaft 1672 to resume the po- Non-actuated position as a result of the tension of the springs 1675 to 1678 causing the retaining pawls to move to the normal position in engagement with the teeth of their respective racks 1640 to 1643.

   The control pawls 1611 to 1614 are then free to return to their normal position in front of the first tooth of their respective racks 1640 to 1643. The pawls 1611 to 1614 are kept under tension against their respective racks by springs 1679 to 1682.



   When the 1561 relay has been actuated, its frame attached to the retaining pawl 1627 disengages the pawl from the teeth of the digit control bar 1625 and at the same time lifts the operating pawl 1630 from its socket with the digit control bar 1625 .When the bar

  <Desc / Clms Page number 81>

 digit control 1625 has been moved as a result of the action of relay 1506, a tension is placed on the spring 1629. When detaching the pawls 1627 and 1630, the tension of the spring 1629 brings the contact bar of figure 1625 to return to its normal position.



   As the racks 1640 and 1643 returned to normal, they caused the different vertical rows of contacts to turn on and off and at the same time the racks 1673 caused the relay 1507 to operate as it had done so when the selection pattern was established, which keeps the circuit between contact 1519 and the tens contacts open and once again prevents erroneous operation.



   When the rack 1643 returned to its non-actuated position and the contacts of group 1578 were opened, the battery via contacts 1597 and 1556 of the trip mechanism to earth via the winding of relay 1511 was disconnected, which causes this relay to drop and allows the scanning arm to return to normal if it is not kept in operation by a closed contact 1578 on another selector circuit.



   Non-functioning indication and warning circuit.



   When contact arms 1535 and 1536 of the operating arm of a selector do not engage contact legs 1520 and 1521 which are in series with the selector multiple band 204, at the same time as the contact arm 989 of a responding line equipment encounters this selector multiple band, relay 1509 does not operate so relay 1508 remains latched in its actuated position. Relay 1503 has operated when the calling line has been activated. connection but 1509 is not activated; therefore, relay 1512 is not actuated so that the rack operations continue and carry the control fingers.

  <Desc / Clms Page number 82>

 tact 1535, 1536 and 1537 upwards to the contact lug 1522.

   Earth is located on contact finger 1537 by switch strip 1539 and brush 1538.



  When contact arm 1537 meets contact lug 1522, a circuit is complete from ground on contact arm 1537 through contact lug 1522, the coil of relay 1514, the coil of relay 1509 to the ground. battery by closing contact 1588 of relay 1503, to operate relays 1509 and 1514.

   When relay 1509 operates it releases the locked contacts of relay 1508, which de-energizes relay 1510 which interrupts rack operations. Relay 1509 also causes relay 1512 to operate by connecting the battery to the earth located on its winding. The operation of relay 1512 causes its bar 1533 to move and closes the closing contact of this relay which establishes a battery path through the closing contact 1502 of the relay 1503 to the earth via the winding of relay 1512, which keeps this relay energized while the calling subscriber is connected.

   When the bar 1533 has moved the pawls 1531 and 1532 have been disengaged from the rack 1530, which causes the rack 1530 to return to normal by driving the entire inner frame of this selector operating arm towards its normal position: When relay 1514 has operated, its armature has disengaged from signal 1515 which causes the end of the signal to drop and gives a visual indication of the selector which has not established its connection. . At the same time, relay 1514 is locked in the actuated position '- starting from the earth by one of its windings, by one of its closing contacts towards a closed contact on the key not locking 1517 and towards the drums.

   At the same time the closing of the other closing contact of relay 1514 has placed the earth on an alarm bell 1516 on which the battery is located by means of the key 1517 and operated.

  <Desc / Clms Page number 83>

 buzzer, for an audible indication of the absence of operation of a selector circuit Relay 1509 was energized when contact finger 1537 moved away from contact tab 1522 when operation of relay 1512 caused the inner frame of the selector circuit operating arm to return to normal. Disconnection by the calling subscriber de-energizes relay 1512;

  its bar 1533 returns to the normal position and the clicks 1531 and 1532 come back into engagement with the rack 1530 with their points resting under its upper tooth. The relay 1514 and the bell 1516 are released by a momentary actuation, by hand, of the key 1517.



   In order to explain more clearly the principle employed in the present invention for choosing called lines, FIG. 22. We have shown in this figure possible combinations of the numbers 1, 2 and 3 with four operations for maneuvering the dial. The number of lines which can be chosen is 3 at the 4th power, or 81. If the numbers 1 to 5 were used for four dial maneuvering operations, the possible selections would be 625 or the value of 5 at the 4th power.



  As the dial usually used in the telephone provides the ten-digit value in pulses, a system of 81 lines will in practice employ two dial operations only, which allows selections amounting to the value of 10 at the second power. or 100. However, an initial installation only requires two operations of the control unit and if it is assumed that the number of lines in the following sequence exceeds 100, the practice shown in fig. 22 would be adopted for the initial installation. would make it unnecessary to change the call numbers of lines involved in the initial installation when the system is extended. To use an exaggerated example, if the employed system shown in fig. 22 is extended from 81 lines to 10,000 lines,

   the digits 4 to 0 would also be used in an operation.

  <Desc / Clms Page number 84>

 maneuvering ration of the dial and the initial 81 lines would retain the same identity.



   It will be noted in fig. 22 that two conductors 2003 and 2004 enter the network from the exploration contacts 1518 and 1519. The conductor 2004 extends to a common conductor through the group of thousands of contacts and that if one contacts 1,2 or 3 in the thousands group is closed, a common conductor representing this thousand in the hundreds group will be connected.

   If then any vertical row of contacts in the group of hundred is closed, continuity is established from scan contact 1518 by contact 1657 only in the group of hundreds to a conductor extending to the line equipment. by the numbers 1111 to 3333 in vertical rows, on the right side in fig. 22, in which the wiring of a typical relay of the response relays 504 and 504 'is shown at 3333.



   Conductor 2003 extends from scanning contact 1519 to a common conductor 1657 in the group of dozens of contacts or closing any one of the contacts 1, 2 or 3 carries the circuit to a common conductor representing this. contact in the contact group of the units Closing the three vertical rows of contacts in the group of contact units establishes continuity of the scan contact 1519 through a single contact 1657 in the group of units to a conductor extending to straight line equipment.



   It will be assumed that the call number 3213 has been dialed in. Contact 3 in the thousands group is closed, the contacts of vertical row two in the hundreds group are closed, and continuity is established between the conductor 2004- and the conductor 32, which connects one side of the coil of the relay 504 'of the nine lines of the system whose call number begins with 32. These neutral lines are

  <Desc / Clms Page number 85>

 lines 3211, 3221, 3231, 3212, 3232,3213,3223 and 3233.



  Contact 1 in the tens group is closed, the contacts of vertical row 3 of the units group are closed, and continuity is established between conductor 2003 and conductor 13, which connects the windings of the relays. 504 of the nine lines with telephone numbers ending in the number 13. These nine lines are the lines 1113, 2113, 3113, 1213, 2213, 3213, 1313, 2313 and 3313. While nine relays 504 are connected to the conductor 32 and nine are connected to conductor 13, there is only one relay 504 which is powered by conductor 13 and this is line equipment relay 504 with the call number 3213.



   When battery is applied to scan contact 1519 and tare is applied to scan contact 1518 relay 504 of line equipment 3213 operates. A closing contact of relay 504 establishes a. circuit of the control equipment not shown in FIG. 22 and by the other winding of relay 504, which keeps this relay actuated for the duration of the communication.



   The 2001 and 2002 multiple threads extend to similar contacts of hundreds and units of other selectors.



   Fig. 21 shows the cabling that would be required for a 10,000 line system. Line 2101 represents the conductor which connects the contacts of. selector to the group of hundreds of relays 504 '; 2102 the group of hundreds'12, 2103 the group of hundreds 13, 2104 the group of hundreds 14 and 2105 the group of hundreds 15. Line 2106 represents 95 wires each of which would extend from the selector contacts to a group of 100 of the 504 relays, namely the 16 hundreds group, to the 00 hundreds group. Line 2107

  <Desc / Clms Page number 86>

 is typical of the 100 unit wires extending from selector contacts to relays 504. As seen, it represents the conductor of units 11: but is typical of conductors of units 11 through 00.

   Each conductor is connected to 100 of the relays 504.



   Claims.



   1 / Telephone system provided with a non-digital switching device, associated with each subscriber line, in which when a call is started, the switching device associated with the calling line is put into operation automatically for lift a free recorder which answers the digits transmitted by the calling party and seizes the desired line, the conversation circuit between the calling line and the desired line being completed by jerky operation, under the control of the recorder, of the switching device associated with the desired line.



   2 / Telephone system provided with a non-digital communication system associated with each subscriber line, in which the switching devices have access to multiple series of contacts and the start of a call causes the jerky automatic operation of the switching device associated with the calling line to find a free series of these series of contacts, means being provided which, in response to the digits formed on the dial by the calling participant, cause the jerky operation of the switching device associated with the desired line to put this switching device in position on contacts which are connected in multiple to those on which the first mentioned switching device is located.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

3 / Telephone system provided with a non-digital switching device associated with each subscriber line, in which each switching device has access to a certain number of recorders by lines of the anointing re - <Desc / Clms Page number 87> linked in multiple and the start of a call causes the automatic jerky operation of the switching device associated with the calling line to enter a free recorder which responds to impulses transmitted by the calling party and selects the caller. desired line, conversation communication between the calling line and the desired line being effected by the jerky operation of the switching device associated with the desired line, under the control of this recorder, to a position in which the switching device in question is connected to contacts which are joined in ultiple with those on which the switching device mentioned in the first place is located. 4 / Telephone system provided with a non-digital switching device associated with each subscriber line, in. which a number of recorders accessible to all switching devices are intended to respond to impulses transmitted by the calling party to bring the desired line to be taken into service, while the completion of a conversation circuit between the calling line and the desired line is effected by the jerky synchronous operation of a switching device provided in the recorder and of the switching device associated with the desired line until the latter is in a position giving access to the switching device associated with the calling line. 5 / Telephone system provided with a non-digital switching device associated with each subscriber line, in which the switching device associated with a line called is intended to be daisi by markings applied to two conductors from a Recorder which is taken in service at the start of a call and responds to impulses transmitted by the calling party, the completion of the conversation circuit between the calling line and the called line being effected by operation subsequent jerking of the switching device in question under control <Desc / Clms Page number 88> of the recorder. 6 / Telephone system provided with a non-digital switching device associated with each subscriber line, in which the switching devices are each provided with two wires arriving at them from a recorder which is taken in service when initiating a call and responds to digits formed on the dial by the calling party, the arrangement being such that in response to the recording of a pair of digits transmitted by the calling party, markings are extended by means of a conductor of all switching devices associated with lines having this pair of digits in their indicative numbers, and in response to the registration of another digit or pair of digits, markings are extended by means of the other conductor of all switching devices associated with lines having that other digit or pair of digits in their indicative numbers, so that for any desired number transmitted by the calling participant, markings are extended only by the two conductors of the switching device attached to the line corresponding to this number to bring about the taking into service and operation of this switching device. 7 / Telephone system provided with a non-digital switching device associated with each line, in which a recorder is taken into service by the operation of a switching device associated with a calling line and responds to the digits transmitted by the calling participant, and means have been provided whereby if several recorders are taken into service substantially simultaneously, the recorders are operated successively to enter the switching devices associated with the appropriate called lines and control their operation. $ / Telephone system provided with a non-digital switching device associated with each line, in which a distributor arrangement has been provided for assigning a determined choice. <Desc / Clms Page number 89> switching devices, the arrangements being such that in the case of substantially simultaneous outgoing calls, the operation of more than one switching device is inhibited during the initial out-of-normal advance, and the operation of A higher choice switching device is delayed until a lower choice switching device has completed the initial advancement out of normal, while subsequent operation of the switching device is allowed to occur regardless regardless of the state of other switching devices. 9 / For use in a telephone system, a switching device comprising a sliding trolley intended to be associated with a rack which is actuated by jerks by means of a pawl controlled by a continuously rotating cam, the pawl being coupled to the cam after the switching device is taken in service and means for locking this slide carriage in any desired position. 10 / For use in a telephone system, a device for recording digits transmitted to it, and comprising a bank of pairs of contact springs arranged in rows and columns, of, means of choosing a row of contact springs. pair of contacts in response to receipt of a digit, and means for closing all pairs of contacts in a column in response to receipt of a second digit, which selects and closes a particular pair of contacts representing the number formed by the two digits. 11 / telephone system according to claims 1 and 3 to 7, wherein a recorder which responds to pulses transmitted by the calling participant contains a non-digital switching device, and the conversation circuit is completed by the synchronous operation of this device switching device and switching device <Desc / Clms Page number 90> tation associated with the desired line. 12 / The telephone system according to claims 1 to 7, wherein a recorder responds to impulses transmitted by the calling participant and means are provided which in the case of simultaneous calls, cause the successive operation of the recorders to take service. switching devices associated with the desired lines. 13. Telephone system according to claim 12, in which these means are provided in common for the recorders and are associated with a recorder only during the taking into service of the switching device associated with the desired line. 14 / A telephone system according to claims 12 and 13 wherein said means operate continuously until no other recorder requests to be associated with a switching device. 15 / A telephone system according to claims 12, 13 and 14, wherein these means comprise two friction arms established for continuous rectilinear movement with a view to successively engaging with contacts associated with each recorder. 16 / The telephone system of claim 15, wherein when the walker arms have completed their prescribed rectilinear movement, contacts are actuated mechanically to return the walker arms to normal, after which the movement is repeated if there is at least one recorder requesting connection with a switching device. 17 / telephone system according to claims 1 to 4, wherein the switching device associated with a called line is intended to be taken into service by markings applied to two conductors extending towards it from a recorder. 18 / Telephone system according to the claims <Desc / Clms Page number 91> 5, 6 and 17, in which the markings cause the successive operation of two relays which initiate a jerky movement of the rubbers of the switching device. 19 / Telephone system according to claims 5,6,17 and 18, wherein the completion of the marking circuit in the recorder causes the initiation of jerky operation of the switching device in the recorder. 20 / telephone system according to claims 18 and 19, wherein the switching devices associated with the recorder and the called line are operated in synchronism until the second recorder device reaches a determined position. by the first switching device, in which it has access to contacts which are connected in multiple to those on which the switching device associated with the calling line is located. 21 / Telephone system according to claims 17 and 18, wherein in the case of lines associated with a PBX and having the same call number, the conductors contain closing contacts of the two relays, so that incoming calls are directed to successive PBX lines. 22 / Telephone system according to claims 17 and 18, wherein one of these conductors is open if the desired line is not available, which prevents the operation of a test relay in the recorder but allows the operation, in a local circuit, of an occupancy relay connected in parallel with the test relay. 23 / Telephone system according to claims 1 to 5, wherein the conversation current is supplied to a calling line from a recorder which controls the establishment of the communication and is sent to a called line by means of the winding of a relay which, when the line is calling, is used to initiate operation <Desc / Clms Page number 92> jerky switching device. 24 / telephone system according to claims 1 to 4, wherein if a switching device associated with a calling line does not find a free outlet, an indicator is actuated and the switching device is returned to normal, after which it begins to new search operation. 25 / The telephone system according to claims 4 and 11, wherein if the two switching devices fail to complete the conversation circuit, a warning is given in the two switching devices. 26 / The telephone system according to claims 1 to 6, wherein ringing current is transmitted to a called line from the switching device associated therewith. 27 / A switching device according to claim 9, in which the pawl is attached to a bar arranged for longitudinal movement and the controlled end of the bar is normally kept out of engagement with the cam until that the switching device is taken into service, the operation of a relay then causing the controlled end of the bar to fall onto the cam. 28 / A switching device according to claim 27, wherein the bar is controlled by a different relay depending on whether the switching device is taken in service for an outgoing call or an incoming call. 29 / Switching device according to claims 27 and 28, wherein during an outgoing call, the bar is controlled by a relay which is looped through the calling line and which during an incoming call, four- Nit the battery to the calling line. <Desc / Clms Page number 93> 30 / Switching device according to claims 27 and 28, wherein during an incoming call, the bar is controlled by a relay which is activated by a prolonged marking to the switching device coming from a recorder which controls the establishment of communications. 31 / Switching device according to claims 9 and 27 to 30 wherein when the wipers have reached a determined position, the wiper carriage is locked in position and the pawl is withdrawn from its engagement with the teeth of the rack , which then returns to its normal position. 32 / A switching device according to claim 9, wherein the wiper carriage is provided with two series of wipers which move in a vertical direction to cause the successive engagement of each series of wipers with a corresponding series of fixed contacts of a bench. 33 / A recording device according to claim 10, wherein the means for choosing a row of pair of contacts consist of a single row of pairs of contacts which are successively closed upon reception of the pulses of a digit, each pair of contacts. contacts in the row being connected to a different row in the contact bank. 34 / A recording device according to claims 10 and 33, wherein the pairs of contact springs are actuated by means of a cam device which moves rectilinearly in accordance with the pulses received in order to successively engage with operating devices provided on each pair of contacts or column of pairs of contacts, in order to effect the closing of. contact pair or column of contact pairs. <Desc / Clms Page number 94> 35 / A recording device according to claim 34, wherein the cam has the form of a projection on a rack which is actuated in accordance with the pulses moved by an electromagnetically controlled pawl. 36 / A recording device according to claims 10, 33, 34 and 35 wherein there are provided several contact benches and several associated contact rows, depending on the capacity of the office, the different rows and the different benches being actuated successively in concordance with the different digits transmitted by the calling participants. 37 / Telephone system, in substance as described with reference to the accompanying drawings. 38 / For use in a telephone system, a switching device substantially as described with reference to the accompanying drawings. 39 / For use in a telephone system, a recording device substantially as described with reference to the accompanying drawings.