BE489876A - - Google Patents

Description

       

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  .SYSTEM 1) 1 !. C0lJft.1UTTIOH T6LJ !, PHOtUU

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The present invention relates to an improved switching system for automatically establishing telephone transmission circuits between subscriber stations under the control of equipment in each of the subscriber stations.



   In telephone communication systems according to the prior art, it was customary to provide each subscriber station with a transmitting and receiving telephone apparatus as well as a calling device which is commonly referred to as a dial or device to be numbered. While a dial device is almost universally used in telephone communication systems today, it has certain drawbacks or disadvantages.



   Firstly, it requires an appreciable time for the subscriber to be able to operate his dial, then it takes an appreciable lapse of time for the dial to come to rest for each digit, during which time the pulses representing the size of the digit are sent to the central office. In this way, to the time needed by the subscriber is added the time needed to transmit and record the impulses to the central office. Likewise, the time required to receive and store the subscriber number at the central office is lengthened by the time required for the subscriber or agent to operate the dial between each of the digits.



   Further, in prior art switching systems, signaling streams representing the designation or number of the subscriber station are transmitted to the central station only once. In addition

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 the subscriber has no way of checking the accuracy of the number transmitted or of determining the part of the number actually transmitted to the central office, so that in the event of an error by one of the subscribers or central office equipment, a wrong number will result.



   In addition, the usual dial pulses are formed by interrupting the direct current supplied to the subscriber line. These pulses have a direct current component and other low frequency components, components which are not suitable for transmission without changing through the voice frequency circuits of trunk lines, current carrying channels, and the like.



   It is an object of the invention to provide improved methods, apparatus and equipment for more quickly establishing communication paths by the equipment located at the central office and thus significantly reducing the occupancy time of the telephone. expensive testing equipment. In this way the efficiency of use of the .ent team is increased and the result is a lowering of the cost of establishing each call.

   Another object of the invention is to provide improved methods, circuits and equipment for more accurately establishing connections by the equipment, first, by arranging the subscriber's calling device in such a way. that the subscriber can dial the number of the called party on the equipment and then check the arrangement of the equipment before placing the call.



   Another object of the present invention is to provide methods, circuits and equipment for more accurately establishing links by switching equipment by repeatedly transmitting the number to the central office where the received number can be verified for s. 'ensure that it has been properly received.

   If the number

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 is not correctly received, the registered number will be left out and the next time it is transmitted by the subscriber station it will be registered again and if it has been correctly received it will be used to order. call establishment, Abrs, after all selections have been made to establish a circuit through all switching equipment to the called subscriber's station, the calling device at the calling subscriber station is automatically disconnected from the line to the central station and the transmitting and receiving telephone equipment connected to the line.



   Briefly, according to an embodiment of the invention given by way of example, the circuits and the equipment are arranged in such a way that a subscriber, when initiating a call, first settles his call. equipment or calling device according to the number or other symbols designating the station of the called subscriber. Then, the subscriber will pass his call by lifting the receiver or handset in the usual manner, at which time the calling equipment is connected and kept connected to the line extending to the central station. The subscriber, by initiating a call, will switch on the central station equipment to extend his line to the call reception and recording equipment.

   When this link is established, the pulses transmitted from this equipment of the calling subscriber will be received, recorded and verified by the receiver.



  Then, the recorded pulses are used to selectively control connectors to extend the link from the subscriber to the called subscriber's line. When the selection of the called subscriber line is completed, the state or electrical states applied to the calling subscriber line are changed, which change disconnects the subscriber's call equipment from the line and connects to it

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 telephone transmission and reception equipment.



  If the called line is busy, the subscriber will then receive a busy signal, after which he will hang up. If the subscriber wishes to call back later, it will be noted that his calling equipment is already set to the desired number so that he can repeat the same call again by simply lifting the receiver off its hook again or lifting the handset, as the case may be, after which the circuits operate again as described above.



  If the called line is free, the inrush current is applied to it. When and if the subscriber answers, the calling current is 8t from the line; the proper electrical condition is applied to the line to cause the telephone transmission apparatus of the called subscriber's station to be connected to his line, and the communication path between subscribers is established in such a way that they can communicate with each other. When the communication is completed, the circuits and apparatus are all returned to their free and available condition.



   The objects and features of the present invention will be more easily understood from the following description read with reference to the accompanying drawings, in which: - Figures 1 and 2 show in schematic form the various elements of the invention. an exemplary system comprising the present invention and the manner in which they cooperate with each other, Figure 3 shows the manner in which Figures 1 and 2 are placed next to each other. another to illustrate the exemplary system described herein;

   - figure 4 shows the way in which figures 5 and 16 are arranged next to each other, and - figures 5 to 16 show with more

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 details the various elements and how they cooperate to form an exemplary system comprising the present invention.



   Twelve subscriber stations are shown in Figure 1. One subscriber station is shown generally by reference numeral 110 and another is shown at 120. Other subscriber stations are indicated by rectangles such as 115. , 116, 117, 118, 119 etc. While only twelve subscriber stations are actually shown in the drawings, it will be understood that any suitable or desired number can be provided without departing from the present invention or the system. - born as an example detailed here to explain such a system. The subscriber station shown generally at 110 is connected to line 114 extending to the central switching station.

   This subscriber station comprises a telephone set 112 which includes transmitter and receiver and other equipment normally provided as part of a subscriber telephone set. The subscriber equipment 110 also includes a dial or call device 113.



   The subscriber station 110 also includes a polarized relay 111 which is used to connect either the telephone set 112 or the calling device 113 to the transmission line 114 extending to the switching station. Central Relay 111 is controlled by line 114 extending to the central switching station as will be described below.



   The subscriber station 120 is similar to the subscriber station 110. The telephone apparatus 122 is provided and includes a telephone transmitter and receiver which is employed in the usual manner as a telephone converser.



  Likewise, the calling device 123 is also provided for passing a signal and controlling the switching station.

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 central office to set up a desired telephone transmission path to the called subscriber station.



   In the case of the subscriber station 120, however, a neutral relay 1 121 is provided instead of a polar relay (/) as provided for at station 110. When a neutral relay 121 is used, it is necessary to provide rectifiers. 124 and 125 to cause relay 121 as well as the rest of the subscriber station equipment as well as the central station equipment to respond appropriately to the various circuits, as will be described below.



   The switching equipment of the central station comprises an er.se.ible of cross-bar switches and associated command or control circuits as well as circuits responding to the signal emitted by the calling devices 113, 123 and similar devices of the others. subscriber stations. As seen in Figure 1, crossbar switches 130 and 140 show two switches of a primary group of crossbar switches, while switches 150 and 160 represent two switches of a second group of primary switches, Only two switches of each of the two primary switch groups are shown in the drawing. It is obvious that the usual arrangement will include up to ten primary switches and multiples thereof in a primary group.

   You can provide as many primary groups as you want. Switches 170 and 180 represent two switches of a secondary group of switches. Likewise, switches 190 and 195 represent two other secondary switches of a second group of secondary switches. Usually there will be as many groups of secondary switches as there are primary groups and the secondary groups can comprise up to ten switches included. Switches 210 and 220 represent two switches of a group of tertiary switches.

   Or-

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 As the previous switches, a switch 230 or a group of such switches are used to connect the recorder circuit to receive the signaling pulses designating the called subscriber which have been transmitted on the subscriber line, to the central switching station * Each of the crossbar switches is provided with a group of pick / pick sometimes called horizontal magnets and another group of magnets called vertical or hold magnets, The operation of a pick magnet and of a hold magnet causes the contacts at the crossing points of the selection magnet and the hold magnet to function to establish a transmission path through this switch.



  After that the selector magnet can be released (no longer energized) without releasing the cross point contacts. As long as the holding rhymer remains actuated the actuated cross-point contacts remain actuated. The holding magnets are designated by H in the drawing and the selector magnets by S.



   In addition, a cold cathode discharge tube is associated with each of the selection magnets and with each of the holding magnets of the primary switches.



   Each of the subscriber lines, such as 114 and 126 and the subscriber lines associated with other of the subscriber stations shown in Figure 1 terminate in a vertical column of contacts on the primary line switches. mayors. Thus the line 114 coming from the subscriber station 110 ends in the vertical associated with the holding magnet and the control equipment 133. The subscriber line 126, extending towards the station 120, ends in the vertical associated with the holding magnet and with the control equipment 132. Similarly, the subscriber stations 116 and 117 which are not shown in detail end in the columns

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 vertical switch 140.

   The other subscriber lines similarly terminate in the vertical columns of the crossbar switches listed above or other primary crossbar switches. If desired, the subscriber line could be connected to horizontal contact lines provided other detail changes are made in the circuits as well.



   In addition to the foregoing, a group of circuits often referred to as trunk circuits, such as circuits 175, 185 186, 187 are provided to aid in the establishment of transmission paths by the system as well as to power the conversation battery. after the connection has been selectively established. Also, the common release circuit 233 is provided to release the control circuits after each communication path has been established by the switches so that these control circuits can be employed to establish another path by the system. of commutation.



  As will be understood, releasing the command or control system employed to establish a path through the system does not release the switching path established by those circuits. Instead, the route by the system is maintained under subscriber control as will be described below. Likewise, the recorder control circuits 234 and 235 and the associated receive and store equipment have been provided to receive the pulses representing the called subscriber station and to select the route by which the call is to be made. directed to the called subscriber station.



   All paths which are free between subscriber lines or primary switches and a transmission circuit or trunk within or extending from-

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 then the interior to the exterior of the central switching station are marked, and then a free path is chosen by the gas tubes arranged in blocking circuits.



   In addition, the designation or number of the called subscriber is stored in a group of relays connected to the tubes in the comparison circuits 237 as shown in figure 2. If desired, the comparison circuit can be used to check the connections. pulses received and the operation of the system, provided of course, that the called station number is known at the central switching station before the pulses representing the number arrive at the central switching place.



   Briefly, when the subscriber of extension 110, for example, initiates a call, the calling device 113 is first set according to the number or designation of the called extension and then this device is connected to the subscriber line. - born 114 extending to the central switching office.



  The initiation of the call by the subscriber also initiates a discharge through the tube associated with this line in the monitoring equipment 133. This tube in turn causes other circuits to be activated, which in turn operate the release circuit energizing relay 251 and preferably 233. Operation of relay 251 applies voltage to conductor 250.



  This conductor extends through the contacts of a relay into each of the free recorder circuits 234 and 235 and such other recorder circuits as may be provided to the conductor 253. However, when one of the recorders becomes free, the voltage of the conductor 250 will be applied by the relay contacts of the recorder circuit which is free. The circuit of the conductor 253 then extends through the breaking contacts of the extra-normal relays of 3 junctors 175, 185, 186 and 187.

   As shown in figure 1, the trunk circuits are arranged in two

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 groups, junctors 175 and 185 being part of one of the groups, junctions 186 and 187 being part of another group '@When only two junctors are shown in each of the two groups, it should be understood that any suitable number Trunks can be provided and can be arranged in any desired number of groups.



  However, for the purpose of illustrating a specific embodiment comprising the present invention two junctors in each of the two groups are shown in Fig. 1. The conductor circuit 253 thus extends through the relay break contacts of the two junctors. of the first group, namely 175 and 185, to the conductor 251 and by similar breaking contacts in the junctors 186 and 187 to the conductor 254. If none of the junctors is free the circuits are incomplete with this result that there is no has no voltage supplied to any of the conductors 255 or 254. However, as discussed, it is assumed that at least one trunk is free.

   If one trunk in each group is free, voltage from conductor 253 is applied to conductors 254 and 255. Conductors 254 and 255 extend through the break contacts of relay 196 to conductors 256 and 257. The conductors 256 and 257 extend to the break contacts of the holding magnets associated with the secondary crossbar switches. Thus the conductor 256 extends to the breaking contacts of the holding magnets associated with the switches 180 and 195 while the conductor 257 extends through the breaking contacts of the holding magnets associated with the switches 170 and 190. If the different vertical circuits of these switches are occupied, the holding magnet will be actuated and thus break the bond of conductors 256 to 257 by the break contacts of the actuated holding magnets.

   However, if these elements are free the magnet

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 will be released and will extend the circuit of conductors 256 and 257 to the elements of the tubes associated with the horizontal lines of contact? primary crossbar switches * Thus the voltage of the conductor 250 and the starting relay 251 of the release circuit and preferably 233 extends uar all the free paths between the primary line switches and the trunk circuits, provided naturally that there is a free trunk, and a free recorder for use by establishing a communication from the subscriber station 110.



   As the subscriber line 114 terminates at switch 130, it will be necessary to operate one of the tubes associated with the horizontal magnets in switch 130. In order to achieve this, it is also necessary to provide for a test. simultaneous setting by some other cross-bar switch, thus the tubes associated with the horizontal magnets of all the primary line switches are arranged in a blocking circuit such that only one tube can operate at a time.

   After operation or conduction of a clean tube to a horizontal line of contacts of switch 130, a path is chosen and then established by the switching system to a trunk circuit such as 175 and from the trunk circuit to the recorder connector switch (s) 230 to the recorder circuit 234 and to the pulse receiving apparatus 236 and 237. A negative battery pole is connected to the tip of the line extending to the subscriber station and the earth is connected to the ring.

   The pole relay 111 at the subscriber station 110 has its winding connected to the line so that its abmature will remain in contact with the right contact as shown in the drawing when the battery and the earth are connected to the line. 'subscriber, linking and now

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 in this way the call or dial equipment 113 linked to the subscriber line.



   After the establishment of a communication path from the call equipment 113 to the subscriber station 110 to the recording equipment, i.e. 234, signaling pulses are transmitted from the call equipment 113 to the recorder control circuit 234 and then through the tip and ring conductors denoted by 273 in FIG. 2, to the receiving equipment 236. This equipment comprises a low pass filter 260 and a limiter or gain regulator 261, a converter circuit 268, an outgoing circuit 264, a counter circuit 262 for checking the total number of pulses received representing the designation of the called subscriber station, the directing circuit or scaling of digit 265 and one or more counter circuits 26b.



   When desired or necessary, the master circuit 265 will be arranged to direct the pulses representing the size of the digit in each digit position of the subscriber's designation, to the respective counting circuits and of storage. So in the case of an eight-digit designation, the director circuit will direct or distribute pulses representing the size of the digit in each of the digit positions of the appropriate one of the counting and storage circuits. .



   The digit counter 256 is shown in the drawing.



  It is shown merely as an example, showing the position of the metering and storage circuits of the system and how the metering circuits cooperate with the other elements and circuits of an exemplary system.



   This counter represents any number needed or agreed upon.

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 Number of counter circuits, from one to a maximum number of digit positions in a complete subscriber designation. When, as is the usual case, it is only necessary to use part of the digit positions of a subscriber designation at any switching center, the counter circuit 266 represents the part that is required: area or desirable to employ at any switching center. This part may comprise the first digit position or more thereof, one or more intermediate digit positions or one or more final digit positions of the designation of the subscriber station.

   The counter as shown in the drawing can be used to count and store pulses representing the size of the digits of each of the consecutive or non-consecutive digit positions of the entire subscriber designation.



   The output of the count circuits is applied to several vacuum tubes and associated storage relays shown inside rectangle 237.



   A verification circuit 262 recognizes the complete set of pulses representing a subscriber station designation. If the complete set of pulses, as received at the switching station, does not include the proper number of pulses, the receiver equipment is recycled through recycling circuit 263 and the next set of pulses is used to control a subsequent operation of the system.

   If a suitable number of pulses have been received, the position or setting of binary counters 266 is transferred to the relays of circuits 237 and a signal is transmitted to recorder control circuit 234 after which the blocking relay 269 is actuated by gas tube 270 which is arranged in a blocking circuit comprising other similar tubes and other recorders such as tube 272 and recorder.

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 giator 235. The blocking circuit is provided to prevent more than one logger at a time from entering or using the group circuit number 240. When relay 269 is operating, it connects the positive pole of the battery to three of the conductors extending to number 240 group circuit.

   Applying a positive voltage to the three conductors extending to the number group circuit selects the line circuit tube associated with the called subscriber line and causes a discharge to start through that tube. . It will be appreciated that prior to the operation of the blocking relay 269 certain other circuits operate to prevent the establishment of a link from an incoming subscriber line to another recorder and trunking recorder connector circuit.



   It is also evident that there are ten conductors from each of the recorder circuits extending to the number group circuit for each digit that is desired or required to be employed at the switching office. If it is necessary to use only three digits, thirty conductors will extend from each of relays 269 and 271, and similar relays of all other logger circuits which may of course include more than the two shown, up to 'to group circuit number 240.

   After applying a positive voltage to a conductor of the hundreds group and a conductor of the tens group, and a conductor of the units group, one of the conductors extending from the number 240 group circuit to the tubes of the supply line will have a sufficiently high positive voltage applied by it. / relative to earth / to initiate a discharge in the subscriber line tube associated with the called line if the called line is free . The initiation of a discharge through the subscriber line tube identifies or marks the called subscriber line and causes the various circuits to function.

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 ring to establish a connection from the trunk to the called subscriber station.

   If the called line is busy, a discharge is not initiated in the line tube associated with the called party line and as a result the circuits timeout get out of order (/) and send an opcupation signal which is transmitted to the set. the calling subscriber and his transmission device.



   By establishing the link to the called subscriber line when it is free, the recorder circuit 234 causes the operation of the horizontal or selector magnet of the tertiary crossbar switch associated with the jumper 175. Operation of this magnet causes the operation of additional relays, which relays apply a voltage through the break contacts of the holding magnets associated with the tertiary cross-bar switch to which the junction circuit 175 is connected.

   The circuit through the breaking contacts of these holding magnets then extends through the winding of some of the selection circuits of the secondary switches through the actuated contacts of relay 196 to conductors 256 and 257 which in turn s 'extend through the break contacts of the holding magnets associated with the secondary crossbar switches and then to the discharge tubes associated with the horizontal lines of contact of the primary crossbar switches.

     The tubes associated with the horizontal lines of the primary crossbar switch are mounted in a blocking circuit arrangement which allows a discharge to be initiated by only one of these tubes, after which one of the possible paths from trunk 175 to 'at the line of Part anpelée, such as 120, is chosen.

   Thereafter, the relays and magnets associated with that path are actuated and establish a communication path from trunk circuit 175 to the called subscriber line.

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 peeled which can be 126 for example. After the path identified above has been fully established, release circuit 233 is activated, which in turn causes recorder 234 to be disconnected and the relays of trunk circuit 175 to operate. Operation of relay 176 in trunk circuit 175 reverses the application of battery and ground to the tip and ring conductors extending to calling subscriber station 110.

   This polarity reversal causes the polarized relay 111 of the calling subscriber station 110 to be actuated so that its armature will now make contact with its left contact instead of its right contact, thus interrupting the circuit to the service equipment. call 113 and connecting the receiver and telephone transmission apparatus to the line extending to the central switching station. If the called line is busy, a busy signal will then be transmitted / received by the receiving equipment forming part of the transmission equipment designated by 112 in FIG. 1. The subscriber after noticing this state of affairs will reset his device on the hook or on its support and if he wishes to resume communication later.



   If the called line is free, the inrush current will be applied to it after the connection is established by the crossbar switches as described above. When the called party answers, the ringing tone is stopped and communication between the two sets is established.



   Upon completion of the communication between the two stations, the station equipment as well as the switch equipment in the central network is everywhere returned to its free or normal state / is then available to be used to establish transmission paths for other calls in a manner similar to that described above.



   While it is assumed that the call originates at extension 110 for extension 120, it is obvious that the call

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 can be thrown in either direction from one of these posts to the other or from one of these posts to any other poet. Likewise all stations may be similar to station 110 or station 120 and the system will operate in much the same manner as described above.



   It is also evident that any suitable type of switching equipment can be employed at the central station in cooperation with the calling device of the subscriber station and the receiver circuit described herein forms part of the present application for reference. .



   An exemplary system comprising the present invention is shown in more detail in Figs. 5 to 16 inclusive. Figure 5 shows two subscriber stations in detail and includes a third 570.



  The two posts. one at 510 and the other at 550 are not the same. It will naturally be understood that all the stations connected to the system can be of one or the other type or that there can be some of one type and some of another as shown in figure 5. The station 510 is provided with a call or dial apparatus 520, telephone transmitter and receiver units 512 and 513 and other types of equipment usually employed in telephone sets including the bell 515, the repeater coil or induction 511, switch hook contacts 514 etc. In addition, a switching relay 516 is provided along with rectifiers 517 and 518. The devices mentioned above are all known in the telephone art.



   The subscriber station 550 is provided with similar apparatus comprising a receiver 552, a transmitter 553, hook switch contacts 554, a bell 555 and an induction coil 551, in addition, a calling device. 560 is planned, which may be similar to the device

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 520. As can be seen at station 550, a polar relay 556 is provided for the passage of the telephone transmission and reception equipment to the call equipment and vice versa. In addition, nonlinear resistance devices 526 at station 310 and 566 at station 550 are provided to eliminate or greatly reduce the clicks which may occur during switching, either at the subscriber's station or at the central office.

   Additional subscriber stations are shown in Figure 6 such as 632, 634 and 636 as well as other unnamed subscriber stations seen in Figure 6.



   It will be noted that the polar relay is mounted at the terminals of the line in parallel with either the call device or the voice frequency reception and transmission device, and connects one or the other of these devices. to the line and disconnect the other from the line. On the other hand, the relay 516 is in series with the conversation apparatus when this apparatus is connected to the line but in parallel with the calling apparatus when this apparatus is used. Relay 516 connects and disconnects calling device 520 and the line but bypasses or removes the short circuit of the voice frequency transmission equipment. Also when voice frequency gear is employed, the coil of relay 516, rectifier 518, and shock coil are bypassed by capacitor 519 and rectifiers 517.

   Of course other equivalent means for connecting the windings of the switching relays and their contacts can be employed when desired.



   While the subscriber station calling equipment as well as the central office calling equipment can be of any suitable type, the exemplary system described herein has been arranged to cooperate with a telephone apparatus. call

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 repeat . Likewise, while any suitable type of telephone switching system such as panel or crossbar systems, which systems are well known in the prior art, can be employed at the central switching station, the system given as An example comprising the present invention employs a switching arrangement of the type described below.



   The crossbar switches used to establish links within and through the system have been divided into groups of primary switches, secondary switches, tertiary switches and recorder connector switches. Ordinarily, a primary or secondary group of switches includes ten levels or ten groups of primary switches and ten levels or ten groups of secondary line switches. Each primary level can include any number of switches. In the ordinary case, one, two or three of the switches have their horizontal elements or circuits connected together to effectively form an extended switch or switch tier.

   Each horizontal switch of each level ordinarily has ten lines which are connected together to form a circuit. The subscriber lines terminate on the vertical columns or contact groups of the primary line switches.



  Each level of each of the primary switches connects to a vertical group of contacts in another of ten different secondary switches. The horizontal levels of the switches of the secondary lines are connected to the junctions or circuits going to the different circuits of junctors. In terminating calls, the secondary horizontal levels are connected to the vertical levels of a group of tertiary crossbar switches whose horizontal levels are even connected at the ends

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 opposite of circuits @ of junctors.

   A group of cross-bar switches are also employed to connect the recorder circuits to the calling line to receive the call notification as will be described below.



   When a subscriber 550, for example, wants to make a call, he must first dispose of his calling device according to the number or designation of the station called, then he must remove the handset from its cradle or lift the receiver. switch hook which closes a DC circuit on subscriber line 565, which connects the start earth to the upper terminal of resistor 638 and thus applies voltage conditions to control the tube gap & 13 , which causes a discharge to begin through this gap, then the discharge passes to the main gap but the current is limited in the holding magnet 512 by the resistor 627 so that the aid maintain mant 612 is not working at this time.

   However, the discharge current flowing through the tube, or starting 613 changes the voltages applied to the starting tube / 618, so that a discharge is initiated through this tube, after which a circuit is closed for actuation of relay 619. Relay 619 while operating applies the correct voltage to the left or cathode elements of tubes 621 and 622, so that these tubes will be partially enabled to allow the ignition to be triggered. 'a discharge through them.



   The relay 619, when it is activated, also closes by its right-hand contacts a circuit for the activation of the energizing relay 1010 of the release and preference circuit. The relay 1010 in operation applies a positive voltage from the resistive voltage divider 1020 mounted at the terminals of the batteries 1014 and 1024, to the conductor 1011 which extends through the normal contacts or conductor.

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 tacts for breaking the relays of the two recorder circuits 1150 and 1151 'If either of these director or recorder circuits is free or a similar circuit provided at the central office, is free, the voltage is extended by the breaking contacts of certain relays in normal position, that is to say of relay 1152 of recorder 1151 or of relay 1153 of recorder 1150.

   This circuit then extends through the conductor 1170 through the breaking contacts of the normal relays 715, 716, 815 and 816 of the free trunk circuits and through the breaking contacts of the relays similar to the relays 715, 716, 815 and 816. other jumper circuits. From these break contacts the circuit extends through at least two other conductors 827 and 727 and through the break contacts of relay 661 to the break contacts of holding magnets such as 645 and 646 to control anode of the tubes 620 and 621 which are free and which consequently
De are available for use. In this way all possible switching paths from all free trunks to calling party lines are marked, so that they are available for use by extending the subscriber line to recorder circuit.



   Tubes 620,621 and similar tubes of control circuits 630, 636 and 637 associated with other primary crossbar switches are mounted in a blocking circuit employing blocking resistor 626, common blocking choke 625 and battery 624 Consequently, only one of the tubes such as 620 or 621 will be the site of a complete discharge and transferred to the main circuit through the tube. For illustration, assume that a discharge is initiated by tube 621 and fully transferred to the main gap of that tube.

   Due to the blocking effect of the circuits, initiation and transfer of a similar discharge is prevented through any

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 other tubes similar to this other tube will connect to the primary crossbar switches.



   After initiating a discharge through tube 621, a circuit is closed to actuate the associated horizontal or selector magnet 623 in series with a restart / 720 which is common to some of the horizontal magnets or selection of primary switches.



   Selector magnet 623 is somewhat slow to operate but relay 720 operates very fast and applies the discharge start condition or voltage from the lower break contacts of relay 1012 to the interval control anodes of tubes 710,711 and Similar tubes of other junction circuits. These tubes are mounted in the blocking circuit comprising the blocking resistor 712, the choke 713 and the battery a 714. Therefore / only of these tubes will be the seat of a discharge and transferred completely to the main discharge path in the tube. For this description it will be assumed that the discharge is initiated through tube 710 and completely transferred to the main path of discharge through this tube.

   After a discharge has been established through the main discharge gap of tube 710, a circuit is closed to actuate the selection magnet 643 of the secondary crossbar switch 640. Other selection magnets can be used. also be actuated due to the discharge through the main path of tube 710 but the operation of these other magnets is irrelevant under the conditions allowed here; if other assumptions were made, the functioning of other people would be important in establishing communication.



   The selector magnet 643 is somewhat faster in operation than the selector magnet 523,

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 as a result, the selection magnet 643 operates at about the same time as or before the operation of the selection magnet 623.



   Operation of selector magnet 623 bypasses resistor 627 and thereby increases the current flowing through tube 613 and holding magnet 612, thereby causing this magnet to operate. The operation of the holding magnet 612 together with the operation of the selection magnet 623 closes the crossbar contacts at the cross points in the usual manner and in turn completes a circuit to hold the hold magnet. 612 actuated under the control of the selection magnet 623 regardless of the discharge through the tube 613.



   Further, operation of the selection magnet 623 of the primary switch closes an operating circuit for the holding magnet 646. The operation of the holding magnet 646 concurrently with the previously described operation of the magnet Switch 643 causes the secondary switch contacts at the cross points to close and extends the subscriber station communication circuit 550 through conductor 655 to the jumper circuit 730.



   After initiation of the discharge through tube 621, besides closing an actuation circuit for selector magnet 623 and relay 720 as described above, a circuit is also closed for actuating relay 1013. at the same time. This circuit extends from the positive voltage of the voltage divider 1020, through the break contacts of the relay 1017, the winding of the relay 1013, the main discharge path of the tube 621, the windings of the magnet. selection 623 and relay 72J, at the negative pole of the battery.

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     The operation of relay 1013 applies positive voltage to the control gap anodes of tubes 1155 and 1157 and other similar tubes of other recorder circuits. These tubes are similarly arranged in the blocking circuit comprising the blocking resistor 1158, the blocking choke 1159 and the battery 1160, with the consequence that a declaration is sent through and transferred to the battery. the main interval of only one of these tubes associated with the recorder circuits. For the purposes of the discussion, it will be assumed that a discharge is initiated by tube 1155.

   After initiation and transfer of the discharge to the main control interval of tube 1153, a circuit is closed to actuate the selector magnet 910 of the resistance connector crossbar switch 911, of Figure 9. .



  The selection magnet 910 operates at substantially the same time as the selection magnet 643 or at least before the operation of the holding magnet 646. After the operation of the holding magnet 546 and the extension of the signaling path from the subscriber station to the trunk circuit 730, an actuation circuit is also closed for the holding magnet 912, determining thus the functioning of this magnet.



   Operation of the holding yaw 912, together with the previous operation of the selector magnet 910 causes the crossbar contacts of the crossbar switch to operate in the usual manner, extending the signaling path of the station. subscriber to recorder circuit 1151. At this point, the tip and ring conductors extend from the subscriber station to the coil of relay 1154.



   Since there is a direct current path or bridge between the tip and ring conductors of the line

 <Desc / Clms Page number 26>

 from subscriber to the subscriber station by winding pole relay 556, relay 1154 operates and closes a circuit for actuating relay 1152. Relay 1152 connects earth to the socket conductor or conductor 8 and maintains thus the actuated holding magnets 612, 646 and 912, which magnets in turn keep the signaling circuit / through the switches running from the subscriber line to the recorder circuit 1151.



   The operation of relay 1152 further applies a pulse through diode 1161 and pulse forming network 1162 to the release circuit and preferably shown in Figure 10. Briefly, the pulse of diode tube 1161 is applied to an auxiliary gap of tube 1015, initiating a discharge through that gap, which discharge transfers to the main gap of that tube and is maintained through the main gap for a period of time predetermined as the tube 1016 and the attached circuits dig it.



  Initiation of a discharge through the main gap of tube 1015 causes relay 1017 to operate and removes actuation voltages from the main gaps of the above described tubes 621, 710 and 1155, as well as all of the above. associated tubes. In this way the discharges through the tubes listed above are interrupted and the discharges prevented by all other tubes until the relay 1017 drops again.



  The negative pole of battery 1024 is applied to various anodes of the tubes listed above to aid in the deionization of these tubes which greatly reduces the deionization te: nps so that the discharge will not be initiated against the timing through the tubes after: the subsequent release of relay 1017. After releasing of relay 1017, the switching circuits of the

 <Desc / Clms Page number 27>

 central office are ready to establish further. links by crossbar switches.



   The above described operation of relay 1154 connects ground to conductor 1110 extending to the coil of relay 1510 of the receiver circuit. In order to put the receiver circuit in a state to cooperate with the other circuits of the system, the key 1614 and either the key 1612 or the key 1613 will be actuated. Application to the conductor of the earth / to 1110 causes the operation of 1510, which relay, in operation, removes the terminating resistor 1511 from the signaling circuit extending to the subscriber station and establishes a signaling path from the subscriber station. input repeater coil 1310 to band pass filter 1311.

   The operation of relay 1510 also removes the earth from the upper terminal of capacitor 1310 and thus places the limiting circuit shown in figure 13, in a condition to put the bread of amplifier tubes 1314 and) 1315 under control. current or received pulses. Operation of relay 1510 interrupts the actuation and holding circuit of relay 1512, which relay then returns to idle and removes earth through its lower break contacts of conductor 1410 extending to code detector 1411. 1412 circuit en route, thereby making these circuits ready for subsequent reception of pulses from the subscriber's signaling equipment 560.



   Note that the negative pole of the battery is connected to the tip conductor by the upper winding of relay 1154 and that the earth is connected to the ring conductor by the winding of relay 1154. These connections cause current to flow through l 'winding of relay 556 to subscriber station 550 in the direction that causes the armature of relay 556 to move towards or be held on the contact with its right contact, thus connecting or maintaining

 <Desc / Clms Page number 28>

 ning the subscriber's signaling numbering equipment 560 connected to line 565, extending to the central station, and then by the path described above through the switches to the recorder circuit 1151 and finally to the receiver circuit as shown in Figures 13, 14, 15 and 16.



   When the bracket or hook contacts are switch 567 closed and the relay 556 in the position shown, power is supplied to the drive motor 561 of the numbering equipment 560, from source 564, l The dialing equipment 560 will be operated continuously to rapidly send pulses representing the extension designation of the called subscriber. The pulse transmission equipment comprises a rotating part 561 carrying several magnets and one or more pick-up pick-up reels represented by coil 563, Figure 5.

   Any suitable type of calling equipment may be employed which is capable of continuously repeating pulses representing the full designation of the called subscriber station. Briefly, the calling equipment 560 is arranged to transmit two pulses representing each digit position of the designation of the subscriber station. The size of the digit in each digit position or the character of the alphabet for any other symbol in such a position is represented by the time elapsing between the transmission of the two pulses. Pulse starts are often referred to as a d @@@ part pulse and a stop pulse.

   In an exemplary embodiment of the invention, these pulses are of short duration and have a fundamental frequency within the voice frequency domain of the signaling path extending to the central office. These pulses are arranged to be transmitted by such signaling paths and thus preferably have no direct current component. As stated, in the modes of -28-

 <Desc / Clms Page number 29>

 Preferred embodiment, the pulses have a waveform which approaches very nearly a single cycle of a 1000 cycle wave. This fundamental frequency is reasonably close to the mid-band frequency of the filter network 1311 and also the mid-band frequency of many voice communication channels.



   In addition to sending two pulses for each of the two digits or signs of a complete subscriber designation, the signaling or calling equipment 560 also separates each group of pulses representing a complete subscriber designation. subscriber, by a blank pose or interval which is significantly longer than the longest interval which can occur between two pulses representing the called station designation and which, in the embodiment given here by way of example of the intention, is approximately equal to the time assigned to the transmission of two characters or digits.



   As long as the pole relay 556 remains in its right-hand position as shown in Figure 5, the signaling equipment 560 continues ± transmitting pulses as described above, representing the designated calling subscriber station, each series of pulses being separated by a blank interval having a longer duration than occurs between any two other pulses representing the subscriber station designation. These pulses are transmitted over the subscriber line 565 to the central station and by the transmission path formed by the crossbar switches, as described above, to the recorder circuit 1151 and to the transmission path. receiver circuit shown in figures 13, 14, 15 or 16.



   The pulses, as received by the receiver circuit, first cause the gain of the limiter shown in Figure 13 to be set to the correct level. In addition these

 <Desc / Clms Page number 30>

 pulses having been repeated by the limiter circuit are transmitted to code detector 1411, which detector is provided with a timer circuit which recognizes the gap or blank between the series of pulses representing a complete designation. The other circuits are rendered ineffective and are blocked until a blank ce interval has been received.

   At this point, the code detector 1411 as well as other parts of the start circuit 1412 respond to the blank interval and cause the various other circuits to be sharpened to then receive the pulses. These circuits then respond to the sucessive pulses received from the subscriber station and cause the magnitudes represented by the various pulses to be stored in binary counters 1413, 1414 and 1415 as shown in Figure 14. It will be understood, of course, that any suitable number of such counters can be provided, one counter being provided for each digit of the called subscriber designation which will be used to control the switching equipment at the switching center.



   When pulses of short duration of the type described above are transmitted over voice-frequency communication paths and by the various types of associated path equipment such as repeater coils, amplifiers, capacitors, filters and the like, the pulses are that transient currents effectively prolong the pulses as received.

   Further, it may be desirable to operate the motor such as 561 of the subscriber station by means of power received from the subscriber line, in which case it is desirable to separate the power streams intended to operate the subscriber. motor, signaling currents generated by the inrush equipment 560. Due to the above factors and also to reduce the effects of noise and external currents, a pass filter

 <Desc / Clms Page number 31>

 1311 tape is planned. This filter also tends to be the site of transient currents due to the application to this filter of signal pulses.

   As a result, a signaling pulse which is about a thousandth of a second in duration is extended or prolonged to about 3 or 3 1/2 thousandths of a second by the effects described above. Therefore, the pulses should be separated from each other by more than this interval. This minimum time interval, together with the length of the pulses and the information to be transmitted by the pulses, requires about 12 1/2 milliseconds to transmit each digit in an exemplary system such as here described.



  In order to more clearly describe the operation of the system it has been assumed that each interval has been assigned to a digit position, has been divided into 25 increments, each increment being slightly less than half a millisecond. Thus, each received pulse lasts for about 7 increments, not including the one in which the pulse begins or is transmitted. In order to recognize the pulses more accurately and to distinguish them from noise and also to make the system less prone to disturbing noise, it is planned to block the receiving equipment for about 7 increments of time following the reception of each pulse.



   As said above, the pulses are received and amplified by the amplifier circuit of figure 13.



  The gain of this amplifier circuit is automatically adjusted so that the amplitude of the pulses of this amplifier is substantially independent of the amplitude of the pulses received. The pulses are then further amplified by amplifier 1428 and then supplied to code detector 1411 and digit detector 1429. As described above, the code detector, together with the interval timer in blen c 1425, recognizes the inter-

 <Desc / Clms Page number 32>

   Valleys in white between a complete series of pulses representing the entire designation of the subscriber station. Digit detector 1429 is normally disabled.



  However, in response to operation of the blank interval timer which in turn actuates the code start circuit 1426, the digit detector 429 is made active so that it will respond to successive pulses received from the device. d @ call 560 from subscriber station 550. The next first outgoing pulse is received by digit detector 1429, which pulse is used to control the square wave generator or and switching device 1431 / on its own. lap to start a timing circuit such as a 1431 multivibrator.

   The switching circuit 1431 also causes the directing scaling circuit and 1433 to conditions the digit directing circuit 1434 such that when pulses are applied to it, as will be described below. - afterwards, they will be sent to the counter and store circuit of the first digit 1413.



   In response to the first start pulse applied to the digit detector, occupant circuit 1430 is actuated, which circuit in turn renders the digit detector unable to respond to any other currents received during the time interval necessary for the transients turn off, or about seven increments of additional time. At the end of this time, the digit detector circuit 1429 is again enabled to operate so as to properly respond to the stop pulse.



  In the meantime, however, the multivibrator or timing circuit 1432 has been arranged to transmit or generate seven cycles or 7 pulses, which pulses or currents are applied to the selective switching circuit 1437. selective switching

 <Desc / Clms Page number 33>

 1437 has been set by the output of the square wave generator 1431 and the switch control circuit 1435 in response to the first start pulse as described above so that the selective switch circuit 1431 drives the first pulses received thereby was transmitted to the counter circuit 1436.

   The counter circuit 1436 counts 7 of these pulses that is to say the pulses received during the time when the transients turn off and the end of the seventh pulse activates the switching command of 1435 so that the switch 1437 is moved to its position or condition where it causes the remaining pulses received from a source 1432 to be transmitted by, the digit directing circuit 1434 instead of the counter circuit 1436. Each successive pulse or cycle from the source 1432 is then transmitted by the digit directing circuit 1434 to the binary counter circuit 1413, which circuit then counts each of the successive oscillations or pulses coming from the timer circuit 1432.



   If the first digit is the magnitude of one, the timer multi-vibrator 1432 will have time to transmit only one pulse to the counter and director circuit 1431 before the stop pulse is received. If the magnitude of the first digit is 5, for example, then 5 pulses will have been transmitted to circuit 14B1. before the stop pulse has been received. Thus, the time of reception of the stop pulse relative to the start pulse is used to designate the size of the digits or character of the designation of the called station code. Receipt of the stop pulse activates digit detector 1429 and square wave generator 1431 to stop operation of circuit 1432.

   The stop pulse likewise causes the detection

 <Desc / Clms Page number 34>

 cipher timer 1429 to be made unavailable for 7 increases in te @ ps during which the associated transients of the stop pulse can be extinguished.



   The next start pulse will then cause the circuits to operate in a manner similar to that described above with reference to the first start scaling pulse except that the @@@@@@@@@@ 1433 circuit will advance. the digit director circuit 1434 and will cause subsequent pulses beyond and above the first 7 of the source 1432 to be transmitted and recorded by the count circuit 1414. Similarly, the magnitude of each of the successive digits is recorded by successive counters 1413,1414, 1415, etc. There will be as many counter circuits provided at each switching station as are necessary to properly control the switches at these stations.

   The pulses representing the magnitude of the respective different digits are selectively stepped through the @@@@@@@@@ and directing circuits 1433 and 1434 and passed to the corresponding digit storage circuits. It will also be understood that in the case where it is necessary to determine the magnitude of all the digits, for example eight in the embodiment described here by way of example, eight counter circuits similar to 1413, 1434 and 1415 will be provided together with suitable control and steering circuits.



   As shown in the drawing, the three count circuits 1413, 1414 and 1415 are employed to record the size of the digits in the first three digit positions of a complete subscriber designation. It is obvious that only one of these counters will be necessary for each quantity of figure which it is necessary to determine. Thus, if it is necessary to determine the size of the first four digits, an additional counter

 <Desc / Clms Page number 35>

 leave employee and connected to the director ciro @ it.



   When it is necessary to determine the magnitude of only a part of the final digits of the subscriber designation, then the counters connected to the first stages of the direction circuits can be omitted and counters provided for and connected to the part. of the master circuit associated with the final digits of the complete subscriber designation.



  In the event that it is desired to determine the size of certain intermediate digits of the subscriber number: counters will be associated with the tubes or director circuit relays made active at the moment when the pulses representing these intermediate digits are / received. . In this case the counters associated with the first stages can likewise be o is and the counting and director stages associated with the final digits can also be omitted.



   Verifiers are also provided to verify the operation of the circuits to ensure that the proper number of pulses have been received. As noted above, two pulses are required to represent each digit. If the full subscriber designation consists of 8 digits, then 16 pulses will be included in each series of pulses between the blank intervals. The output of digit detector 1429 is applied to a 16 pulse counter circuit 1418.



  If more or less than 16 pulses are received by count circuit 1418 between two blank intervals, the circuits are arranged to erase all records and restart in response to the next series of pulses.



   To achieve this, the 16 pulse counter 1419 commands + counter reader 1417. If the counter 1418 has counted anything other than 16 pulses, the counter reader 1417 conditions the recycle circuit 1422 to repeat a pulse from the counter. end of code circuit 1427

 <Desc / Clms Page number 36>

 in response to the next blank interval through circuit 1424 and causes relaia 1513 and 1514 to operate.

   These relays function to record in the recorder 1515 the number of times the system must be recycled and also remove the short circuit bypassing the chokes 1551 and 1552 in the battery supply to the various counting and switching circuits, in so that these circuits are all brought to rest and returned to their initial state, to which they respond again to the successive series of pulses transmitted by the calling device 580.



   If, in the exemplary embodiment described here, a total of 16 pulses are received between the two blank intervals, the counter reader 1417 will condition blocking circuit 1421, instead of recycle circuit 1422. , to repeat a pulse from end-of-code circuit 1427 in response to the next blank interval. Blocking circuit 1421 then operates through circuit 1423 to actuate relay 1516, thereby indicating that the correct number of pulses have been received. Operation of relay 1516 interrupts the actuation circuit of relay 1513, thereby allowing relay 1510 to drop. Releasing relay 1510 reconnects terminating resistor 1511 to the incoming line from repeater coil 131j.

   Releasing relay 1510 again grounds the upper terminal of 1319 thereby returning the gain of the regulated amplifier, shown in Figure 13, to its maximum value. Releasing relay 1510 also closes a circuit to actuate relay 1512, which in turn operates and connects earth to conductor 1410, which in turn renders code detector 1411 unsuitable to respond to other signal currents.



   The operation of relay 1516 completes a circuit

 <Desc / Clms Page number 37>

 obvious for actuation of relay 1518. Relay 1518, when actuated, removes the short circuit bypassing inductor 1551 q @ i returns the square wave generator or switching circuit 1431 and the 16 pulse counter 1418 at their initial or normal conditions.



   The operation of relay 1516 also connects the positive pole of the battery to the anodes of tubes 1520, 1521,1522, 1523, 1624 and 1025. The two sections of these tubes function, as cathode followers and transfer the rolling of the binary counters. 1413, 1414 and 1415 to relays 1531 to 1538 and 1630 to 1633 inclusive. Tubes 1520 and 1521 transfer the condition of counter 1413 to relays 1531 to 1534, similarly tubes 522 1523 cause relays 1535 to 1538 to operate according to the condition of count circuit 1414. Similarly tubes 1624 and 1625 bring relays 1630 to 1633 to operate under the condition or replace control of counter 1415.

   If the call in question is a test call, it is possible to arrange the corresponding switches 1541 to 1548 and 1641 to 1644 according to the code of the test call. Then the lamps controlled by the keys, as well as the lamps controlled by the relays identified above will be on or not depending on the case if the code is correctly received. If the call is not a test call, it is not There is no means provided for checking the operation of the receiving equipment other than the 16 pulse counter described above.



   The operation of relays 1516, furthermore, connects earth through conductor 1111 and left breaking contacts of relay 1167 to the battery, passing through the winding of relay 1169. Relay 1169, actuated, forms a circuit for actuated relays 1012 and

 <Desc / Clms Page number 38>

 661, provided 1013 is released. The relay 1013 will be released unless the commando equipment is in the process of establishing a connection by the switching equipment as described above, between a subscriber line and a free trunk and recorder circuit. If relay 1013 is actuated at this time, the circuits described above will remain in the written state until relay 1013 drops out after the completion of communication establishment, then done by switches.



  After that the relays 1012 and 661 will operate and the relay 1012 will close a circuit to maintain itself and to keep the relay 601 actuated under the control of the relay 1169. The relay 1012 actuated, initiates the operation of the circuits. de / and conditions the control circuits for establishing a transmission path from a trunk circuit to a called line under the control of a register circuit as will now be described. Relay 1012, actuated, first causes the release circuit of Figure 10 to operate and interrupts any discharges through the control circuit tubes which may have been initiated during operation of relay 1012.

   The operation of relay 1012 also prevents the control circuits from responding to any incoming calls until a circuit has been established to the called line, as will be described.



   Operation of relay 1169, together with operation of relay 1012, applies a positive voltage to voltage divider 1020 to drive the gap anode of tube 1163. Tube 1163, in conjunction with tube 1164 and the like in other recorders not shown are all mounted in a blocking circuit comprising resistor 1173 and choke

 <Desc / Clms Page number 39>

 1174, of aorta that a discharge can fire initiated and fully transferred to the main discharge path within only one of these tubes. It will be illustrative that the discharge is initiated and transferred to the main discharge path of 1163 at this time.



   After transfer of the discharge to the main discharge path through tube 1162, relay 1165 operates and connects earth to conductor 1115, it connects the conductors of the recorder circuit to the number group circuit shown in figure. figure 12; It closes a circuit to keep relay 1169 energized and closes a circuit for actuation of relay 1167.



   When earth is applied to contact 1115 which extends through the recorder connector switch to trunk circuit 730, a circuit is closed for actuation of relays 718, 722 and 917 and the selector magnet. tertiary 915. Relay 718 while operating transfers the tip and ring conductors of the recorder circuit to the windings of relay 719, thereby causing relay 719 to operate, and relay 719 while operating connects earth to conductor S and keeps the holding magnets 612 and 646 in action. Relay 718, when operating, closes a circuit through both windings of relay 717, but since current flowing through these windings produces opposite magnetic effects on the relay, the relay is not operating at this time.



   When the tip and ring conductors are transferred from the recorder circuit to the windings of relay 719, the voltage polarity and current direction in the calling subscriber line are reversed. The station pole relay 556 subscriber responds to this reversal and disconnects motor 561 from the power source

 <Desc / Clms Page number 40>

   564, disconnects call device 560 from the line
565 and connects the conversation equipment to the line for the transmission and reception of conversation currents.



   When the tip and ring conductors are transferred from the recording circuit to the windings
719, the actuation circuit of relay 1154 of the 1150 recorder circuit is interrupted, thus allowing this relay to return to idle. Relay 1154, on de-energizing, causes relay 1152 to de-energize and also removes ground from conductor 1110. Releasing redo 1152 removes ground from conductor S of the recorder circuit. Thus, releasing the relays 1154 and 1152 partially restores the circuits to their normal free state.



   Relay 917 operates in series with selector magnets such as 915 and 916 and the other selector magnets of tertiary switch 930. After operating selector helper 915 as described above and operating relay 917, a positive voltage from voltage divider 1020 is applied through resistor 918 and the actuated contacts of relay 917 to the receiver contacts of all holding magnets of tertiary crossbar switch 917 to mark all free paths leading to this cross bar switch. The circuits thus marked by this voltage extend through the normal contacts of the unactuated holding magnets which close circuits extending through the SEL conductors to the selector magnets of the associated secondary cross-bar switches.

   For example, a circuit extends through the break contacts of the holding magnet 930 and through the first selection ants of switches 647 and 670

 <Desc / Clms Page number 41>

 and other like magnets of like switches not shown in the drawing. Likewise, a circuit extends to the breaking contacts of the holding magnet 919. when this magnet is released, through the selection aant 641 and the corresponding selection magnet associated with a group of selection magnets. 680 and other selection ainants associated with other switches not shown, and then by the actuated contacts of relay 651 and then by the breaking contacts of the free holding magnets of the corresponding secondary crossbar switches.



  From these contacts a circuit then extends through the primary selection levels associated to cor.nander the anodes, tubes 620, 621 and. the corresponding cubes of the other primary switches associated with free paths which can be used to establish a link from the called subscriber line to the trunk circuit 730.



   After connecting the input conductors to the name grouping circuit by the operation of relay 1165, the first four relays 1531 to 1534 which have been put in position by counter 1413, in response to the magnitude of the 'one of the digits assumed to be the first digit of the called subscriber number, apply positive voltage from battery 1112, through conductor 1113 and the break contacts of relay 1167, conductor 1114, upper contacts of relays 1531 to 1534 , to one of the thousands conductors designated A in Figures 15 and 11. Similarly, the second set of four relays 1535 to 1538 connect a positive voltage from the same battery to one of the hundreds conductors designated by B in Figures 11 and 15.

   The shimmers 1630 to 1633 which are controlled by the ones digit similarly connect the positive voltage of the same battery to one of the tens conductors designated by c.

 <Desc / Clms Page number 42>

 



   The positive blade of the battery being connected to one of the conductors of the thousands, of the hundreds and to one of the conductors of the one of the units; The left terminals of the group of numbers circuit will have a positive voltage substantially equal to the positive voltage of the battery 1112 connected to it. All other terminals will have applied much lower voltages to them. The voltage of this single conductor, which is assumed to be conductor 211, extending to tube 616, is: the magnitude sufficient to initiate a discharge through the auxiliary gap of tube 616 if the called line is free .



  If the called line is busy, the main cathode of tube 616 will be at earth potential instead of negative voltage, with the result that the voltage applied to conductor 211 is insufficient to initiate a discharge across the gap. auxiliary. therefore, the circuits remain in the above condition until the control circuits are returned to quiescent by the release circuits operating the release circuits. During this time and until read the calling subscriber hangs up a tone or busy signals are transmitted to the calling subscriber and by his receiving device 552.



   Assume now that the line called 525 is free and that a discharge is initiated through the tube 516, which discharge is immediately transferred to the main discharge path through the tube, and in turn causes a discharge to be initiated through. the tube 618. The tube 618 by becoming conductive, causes the relay 619 to come into action. Relay 619 in turn applies
 EMI42.1
 'lU (' a negative voltage at the control cathodes of inter- '#; #. ":. v; cl .bes j20, 621 and similar tubes associated with ..: .... 1 \' :::; s .the vertical 5-ilcction of the co ^ n: utate, .r with crossed bars.

 <Desc / Clms Page number 43>

 Sées primary 610, thus preparing these tubes for the initiation of a discharge through them since a sufficient positive voltage is applied to their control anodes dan3 the circuits described above.



   The 1167 relay when operating interrupts the circuit
 EMI43.1
 original action of relay l16fj, closes a circuit to keep itself actuated under the control of relay 1516, and interrupts the battery source through the contacts of relays 1531 to 1538 and 1630 and 1633 to the circuit of group of numbers in Figure 12. Tubes 620, 621, and other tubes specific to other primary selection magnets are mounted in an arrangement, the blocking circuits as described above such that only one of these tubes at a time. may have a discharge initiating therein which is fully transferred to the main discharge path through the tube. For explanation, assume that tube 620 is the tube in which the discharge is initiated at this point.

   After the initiation of a discharge through the main discharge path as in tube 620, a circuit will be formed: to operate selector switch 622, relay 820 and relay 1013 .



   The operation of relay 820 at this time connects earth to a group of secondary switch selector magnets comprising the selector magnet inside rectangle 647, thereby actuating the magnet within that corresponding rectangle. to selector magnet 641 and switch 640. Selector magnet 622 operates somewhat slowly and does not operate until relay 840 and the corresponding selector magnet 641 of group 647 have operated. , Then after the operation of the selection magnet 622, the

 <Desc / Clms Page number 44>

 resistor 627 is shorted out and the holding magnet inside the actuated rectangle 614. which closes the corresponding cross points between subscriber line 525 and circuit path 652.

   Closing these crossbar contacts causes the holding magnet corresponding to the holding magnet 646, but associated with the contacts 649 to close and '' extend the switching path 652 to the path 657 because the first magnet of group selection 647 was previously operated as described above.



  After closing these cross-bar contacts and extending the subscriber line circuit to the conductors 657, a circuit is likewise completed for the operation of the holding magnet 930. The holding magnet 930 functions. At this time, with the selector magnet 915 actuated as described above, closes the corresponding crossbar contacts and extends the subscriber line 525 to the tip and right ring conductors of the trunk circuit 730 .

   The closing of the crossbar contacts due to the operation of the selection magnet 915 and the holding magnet 930 closes the circuit for actuating the relay 724 if the called line is free and also applies a voltage to the network 725 pulse generator, which pulse is transmitted by diode 726 to the release circuit at the gas tube 1015, tube which operates the release circuit by actuating relay 1017, which relay in turn removes the positive anode voltages from all control tubes and in turn releases the various selector magnets that have been previously actuated.



  After the discharges in these tubes have been extinguished and the various magnets have been released, timing circuit 2, employing tube 1016, operates and returns the release circuit to its initial state in which the circuits are ready to control. establishment of another communication.

 <Desc / Clms Page number 45>

 



   After the release circuit has operated as described above, the discharge through tube 1163 is terminated and relay 1165 is released. Releasing relay 1165 disconnects the conductors of relays 1531 through 1538 and 1630 through 1633 from the group number circuit shown in Figure 12. Releasing relay 1165 also releases relay 1169.



   Releasing relay 1165 removes earth from conductor 1115 extending to the trunk circuit and then to the lower winding of relay 717 through the actuated inner upper contacts of relay 718. Relay 717 then operates due to the relay. current flows through its upper winding and removes the earth of the conductor S extending to and through the logger connector, thus releasing the actuated holding magnet 912, which in turn releases the contacts of cross-bar switch between the jumper and recorder circuits.



   Releasing relay 1165 at this moment, with relay 1167 blocked in action under control of relay 151o, closes a circuit for actuating relay 1517, from earth, passing through the break contacts of relay 116.5, actuated contacts of relay 1167 and by conductor 1116 which extends to the receiver circuit shown in Figures 15 and 16 and then by actuated contacts of key 1614 and the coil of relay 1517 to the battery. It should be emphasized that the key 1614 is actuated to prevent interference from recorders 1610 and 1611 in the event that such recorders are provided.



  In addition, either key 1612 or 1613 will also be activated to prevent inappropriate operation of relay 1510. Redoing 1517 while operating closes a circuit passing through key 1541, keeping it in action.

 <Desc / Clms Page number 46>

 under the control of relay 1516,
L. relay 1517 while operating also closes an obvious circuit for actuating relays 1519. Relay 1519 operates and removes the shorted bypassing choke coil 1552, which returns to idle @@@@@@@@@@ @@@@@ binary counters 1413,1414 and 1415 and other similar counters as there may be, a blocking circuit 1421, the replication circuit 1422, and the counter reader circuit 1417.



   When blocking circuit 1421 is returned to its initial or available state, it cuts off the current flowing through relay 1516 and thereby allows relay 1516 to drop. Releasing relay 1516 removes the anode battery. The cathode follower tubes 1520, 1521,1522, 1523, 1624 and 1625. The removal of this battery together with the resetting of the counter circuits 1413, 1414 and 1415 causes storage relays 1531 to 1538 and 1630 to 1633 to be returned to their initial free condition. Releasing relay 1516 also interrupts the circuit of relay 1518 thus allowing this relay to drop.



   Releasing relay 1516 thus interrupts the blocking circuit of relay 1167 from earth through the lower contacts actuated from relay 1516 and by conductor 1111 to the battery through the winding and the previous / left contacts of relay 1167. Releasing relay 1167 restores the normal and free state of recorder circuit 1151.



   Releasing relay 1167 in turn interrupts the @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@, so that relay 1517 drops out and in turn releases the relay. relay 1519, thus returning to their free condition
 EMI46.1
 ::gold. have the reception circuits and, ieranaasinement my- # -: # ',, ¯ :. '1 "',. ¯ ¯ .. 13, 14, 15 and 16.

 <Desc / Clms Page number 47>

 



   Under the assumed conditions where the subscriber line is free, the establishment of the communication path to the subscriber line 525 extending to the subscriber line 510 applies the current (ringing, through the contacts. - born from relays 722 and 724, to the subscriber line and activates the subscriber's ringtone 515. When the subscriber answers @ by removing his handset and his port, the tip and the ring are connected together by a path of low impedance passing through the primary winding of the choke 511, the transmitter 513 and the rectifiers 517.

   Sufficient current flows through line 525 and la. path above and through the bell trigger relay
723 to actuate this rflais and release relay 722, after which the windings of relay 71 are connected to the called subscriber line. Note that the earth is connected to the peak conductor by the upper winding of relay 721 and that the negative battery pole is connected by the lower winding of relay 721 to the baue conductor extending to this node. to the line of the called subscriber.

   These voltages have a meaning such that rectifiers 518 oppose the flow of current through them and the winding of relay 516, thus preventing operation of relay 515. Instead current flows at through rectifiers 517 and then through transmitter 513 giving the talk battery to the subscriber's slow transmission team. Thus the voltage applied to the line in such a way that the conversation equipment remains connected to the line and the subscriber's call equipment 525 remains disconnected from the line.



   The relays 721 and 718 then operate and remain activated during the remainder of the communication between the two subscriber stations. These two relays, while remaining actuated, connect the earth to the socket conductor or conductor.

 <Desc / Clms Page number 48>

   turn $ and hold the magnets. of maintenance in action.



   At the end of the communication, when the two subscribers hang up, the two relays drop off and allow the release of the various holding magnets which establish the circuits in their initial or free condition, in which they are ready to go. use to establish other communications between the same subscriber stations or others.



   From the foregoing description of an exemplary system embodying the invention, it is evident that the subscribers :, are provided with anpel devices which, after having been first arranged by the calling subscriber of after the number of the subscriber called, then put into operation by the passing of a communication, repeatedly transmit the number of the station called to the central office.



   Central office switching equipment is arranged to respond to one or more of the complete sets of pulses or currents representing the called subscriber station or station designations. Means are also provided under the control of the central office for connecting the calling device to the line extending to the switchgear of the central office after a call has passed and disconnecting it from the line and connecting the switchgear. usual telephone transmission and supervisory equipment connected to the line shortly after the called line or called line route has finally been chosen.

   The calling device is also disconnected and kept disconnected from the line and the telephone transmission and supervision equipment is connected to the line under central office control when the subscriber answers a call arriving at his station. or to his device.


    

Claims (1)

CLAIMS 1. Telephone switching system comprising a subscriber station (110,120, 510, 550) having a calling device EMI49.1 (520, 560) with a means of cO: 1r. \ UtatL) ll associated (514.554), a switching station (Fīa.7-15), a walnut tree. de cor:, nande r \ .0) con; nutation (Fig. 6, 1010) and a path or circuit portion extending from said subscriber station to the switching station (565, EMI49.2 612, o27, 619, the J1J), caractt: The calling device includes a sinalisaLion \ O'E'r1 (561,53) to repeatedly repeat a called station designation, thereby exerting control over the switching process throughout. the appeal process. EMI49.3 2. CO system "1uut.aLi0n t: ': 1.;,> Ho;: l va2 according to claim 1, characterized in that the doyen .le commutation (51t, 554) of the subscriber station is controlled by currents transmitted from the copulation station, the connutation means connecting and disconnecting thereby the signaling means associated with the calling device (520.5oO). EMI49.4 3. COC system: Jut.;. T: .. ::>: 1 telephone according to claims 1 and 2, characterized in that the means of signaling comprises an electric notor (521,561) to generate a code call pulses. 4. Telephone switching system according to claim 3, characterized in that the calling subscriber can switch off the motor by opening associated horn switch contacts (567). 5. Telephone switching system according to claim 3, characterized in that the motor can be disabled after closing the circuit to the called subscriber. by a reversal resulting from the current flowing through a pole relay (555), said relay disconnecting the motor from its power source (564). <Desc / Clms Page number 50> EMI50.1 o. : 5YStt! 'Ll' telephone switching followed) 1 .. claims 1 and J, cnrp.ct "ris4 on what the transmitted pulses are used for and;"): 1; -, l) r the switching station tation and for Ótendrn. a circuit from the mi subscriber, Alsnt to the subscriber calls. 7. System do cO "\ llut;:., Io'1 ::.,) L. ':) honÜ: 1Jf' according to claims 1 and; 3, charac ',: ri. ^ In that the path ruis - sant the station you; and the; 1: '3'.:. ':::' 1 ('. the switching is a communication path t ,,; ll ;; 1h :: mic voice-frequency , the pulses being sent pnr c tra: v., before the establishment of a circuit cor'l: -1el mit: '- "1 1' calling subscriber and subscriber a;; -. ei:.