Patent GB-209079-A (GB)
Abstract: 209,079. Allmõnna Telefonaktiebolaget L. M. Ericsson, (Assignees of Palmgren, N. G.). Dec. 28, 1922, [Convention date]. Automatic exchange systems; selectors. - In systems in which numerical selectors are controlled by the setting of a register-controller, control impulses are sent out alternately from the register-controller to the selector and from the selector to the register-controller, the circuit arrangements being such that the selector cannot be moved out of any position until the registercontroller has been moved into a corresponding position. Both the selectors and register switches employed are of the kind in which the wipers are moved forward one step at each energization of the control magnet and a further step at the succeeding de-energization. Only each second position, however, is given a numerical designation, the intermediate positions being used for sending out control impulses. The invention is also stated to be applicable to systems using relay sets as selectors and registers. In the system shown, a calling line is connected non-numerically to an idle trunk FL1, Fig. 3, with which is associated a hunting switch RSG which selects an idle register-controller, Fig. 4. The registerccntroller comprises five register switches RE1 - - RE5, two controlling switches PRO, SRO which are mechanically of the same construction as the register switches, and a clutch-driven sequence switch MR. Also associated with the trunk FL1 is a first group selector RV1 and a controlling sequence switch SOG1. The group selector is of the non-hunting type and operates in response to one digit to select a particular group of trunk-finders S3, Fig. 5, which then hunt for the trunk FL1. The connection is extended through a second group selector RV2 of similar type, a second trunk finder and a third group selector (not shown), and a third trunk-finder S5, Fig. 6, to a connector trunk FL4. A finder switch LVS then associates an idle marking set LV, Fig. 7, with the trunk FL4, the marking set comprising tens and units marking switches LV1, LV2, which are of the same construction as the group selectors and register switches and are operated under the control of the register-controller to mark the wanted line, the talking connection being completed over a hunting switch S6. The register-controller and marking set are released as soon as their operations are completed, but the group selectors remain in their operated positions throughout the conversation and serve to hold the connection over the finders S3 - - S5. Construction of switches. The switch shaft VA, Fig. 2, is driven by a spring KF and is released to advance the wipers SK one step at each energization and a further step at each deenergization of the control magnet R, by means of a double pawl VH controlled by the armature MA. The wipers are restored to normal at the end of a connection, by means of a lever (not shown) acting on the projection AV, and, in the system described, this is performed by an arm carried by an associated sequence switch during the movement of the latter into its normal position. In Figs. 3 - - 7, the switches of the above type and also the sequence switches are represented by double rows of contacts, the various positions of the wipers being indicated by dotted lines. Non-numerical switching arrangements. The Specification as open to inspection under Sect. 91 (3) (a) comprises an arrangement in which linefinders and preliminary selectors of the clutchdriven and no-normal types are employed. If, when a subscriber calls, no preliminary selector is resting on an idle trunk, all the accessible preliminary selectors are started up and when one finds an idle trunk FL1, Fig. 3, it is stopped thereon and marks the trunk busy to all other similar switches. At the same time, a call-finder corresponding to this preliminary selector is started, and any other call finders associated, through preliminary selectors, with idle trunks are also started. When a finder reaches the calling line a relay operates in series with the subscriber's cut-off relay to stop all the finders and preliminary selectors. This subject-matter does not appear in the Specification as accepted. Connection to idle register-controller. Relay RS1, Fig. 3, operating in series with the calling line energizes release relay RS2, and completes circuit 8 to drive sequence switch SOG1 into its 2nd position in which clutch magnet KM4 energizes over circuit 9 and starts up hunting-switch RSG. When an idle register-controller REG, Fig. 4, is reached, relay RS6 energizes in circuit 10 to stop the switch and to connect the trunk FL1 to the selected register-controller. Relay RR1, also energizing in circuit 10, closes circuit 13 for driving sequence switch MR into its 2nd position, and circuit 15 for relay RR2 which energizes magnet IM1 to advance the switch PRO one step. Circuit 15 being now broken, relay RR2 de-energizes and the release of magnet IM1 advances switch PRO a second step, and dialling tone from circuit 17 is transmitted to the calling subscriber. Relay RS6 also completes circuit 12 to drive switch SOG1 into its 3rd position and thence, through the operation of relay RS3 over circuit 18, into its 4th position. Setting of register switches. In response to the first impulse repeated by relay RS1 over circuit 20, relay RR2, magnet IM1 and magnet RE1 all energize, and register RE1 and switch PRO are advanced one step. At the end of the impulse, the register RE1 advances a second step but relay RR2 is slow-acting and maintains magnet IM1 energized throughout the digit. The register switch RE1 is thus advanced two steps for each impulse, whilst at the end of the digit, magnet IM1 de-energizes and switch PRO moves a further step to connect up the second register RE2 which is set in a similar manner. Control of first group selector. The movement of switch PRO at the end of the first digit completes circuit 22 to drive switch MR into its 3rd position, in which circuit 23 is closed. Magnet R1 of the first group selector RV1 energizes in this circuit and moves the selector one step, thereby completing circuit 24 for relay RR3. This relay closes circuit 25 to move register RE1 forward one step, and opens circuit 23 to deenergize magnet R1 and move the selector RV1 a second step. Circuit 24 being now broken, relay RR3 de-energizes, register RE1 moves a second step and circuit 23 is re-established. The operation thus continues, the selector and the register-controller alternately controlling one another's circuits until the register switch RE1 moves out of the position corresponding to the numeral O and closes circuit 26 to maintain magnet R1 operated, the selector being stopped in an intermediate position between two numerical settings. Magnet IM2 operates in circuit 27 to advance switch SRO one step. Slow-release relay RS3, which remained operated throughout the movement of selector RV1, now releases and causes switch SOG1 to move into its 5th position in which circuit 24 is broken, relay RR3 falls back, circuit 27 is broken, and switch SRO moves a second step. Magnet IM2 energizes over circuit 29 and moves switch SRO a third step, and if the second digit has been completely registered, as denoted by the opening of circuit 30, magnet IM2 de-energizes again and switch SRO moves a fourth step into position for the control of the second group selector. When the switch SOG1 moved into its 5th position, magnet R1 was deenergized and the group selector moved a further step into, say, the position marked 8. Trunk finder S3, Fig. 5. The clutch magnets KM6 of all idle finders S3 belonging to the group selected by the switch RV1 are energized in circuit 31, and when one reaches the trunk FL1, it completes circuit 32 in which relay RS3 operates to drive switch SOG1 into its 6th position whilst relay RG1 stops the finder and marks the trunk busy. Second and third group selectors. Relay RG1 also closes the circuit 35 to drive sequence switch SOG2 into its 2nd position in which relay RG2 energizes over circuit 36 and switch SOG2 moves to its 3rd position. The second group selecting operation now takes place with the selector RV2 and the register RE2 controlling one another's circuits in the same manner as described above for selector RV1 and register RE1, the control circuits 38, 39 corresponding respectively to circuits 23, 24. When the selector is brought to rest in an intermediate position, relav RG2 falls back and drives switch SOG2 into its 4th position. Finders (not shown), similar fo finders S3, are then started and when the trunk FL2 is reached, relay RG2 energizes over circuit 44 to move switch SOG2 into its 5th position. The control of the third group selector (not shown) takes place in a similar manner, and finders S5, Fig. 6, individual to the wanted hundreds group of the exchange, are then started. When the calling trunk is found, relay RV11 operates to drive sequence switch SOV into its 2nd position. Final selection. Clutch magnets KM9, Fig. 7, of finder-switches LVS are energized over circuit 48, and when the trunk FL4 is found, relay RV1 operates over circuit 49, stops the finder and closes circuit 54 to drive sequence switch MRV into its 2nd position. Relay RV2 closes circuit 52 to drive switch SOV into its 3rd position, in which it is stopped due to the opening of circuit 52 by a relay RV14 which operates over a circuit 53 extending back to the register-controller. Relay RV2 also closes circuit 55 for slow-release relay RV3 which locks up relay RV4 and closes circuit 59 for the control magnet VI of the tensmarking selector LV1. This selector moves forward one step and closes circuit 59 for relay RR3 which advances register switch RE4 one step over circuit 60 and opens circuit 53. Magnet V1 is thus de-energized to advance the selector a second step, which opens circuit 59 and causes the register switch RE4 to move a second step. This mutual