Patent GB-191121259-A (GB)
Title: Improvements in Switching Apparatus for Interconnecting the Lines of an Automatic Telephone System.
Filed: 1911-09-26
Granted: 1912-10-28
Abstract: 21,259. Western Electric Co., [Telephon Apparat Fabrik E. Zwietusch & Co.]. Sept. 26. Automatic exchange systems; coin freed systems; metering systems.-Relates to improvements in the register-controller system described in Specification 26,079/10 in which the selecting-impulses transmitted from the sub stations are received by an easily operated switching-mechanism which afterwards serves to control the operations of the group selectors and connector in establishing the required connexion. The Specification describes and claims numerous features, among which are (1) the use of such register-controllers for translation purposes, impulses received on the decimal system serving to control the operation of 200- point selectors and connectors ; (2) the direct connexion of the register-controllers to the calling line, by means of relays ; (3) the control of the register-controllers by means of sequence-switches ; (4) an arrangement by which, while the registercontroller is receiving and storing up the selecting- impulses, a pre-selected idle call-finder hunts for the calling line and extends connexion to a selector trunk. Construction of selectors, call-finders, and sequence switches. The group selectors and connectors comprise ten sets of brushes, one of which may be tripped for use as fully described in Specification 16,867/11, the construction of the connectors being identical with that described in the prior Specification, except that they are designed to serve two hundred lines, there being ten rows of fixed terminals, each having twenty sets of contacts. The group selectors are also two hundred point switches, and differ structurally from the connectors only as regards the make- and-break interrupter arranged at the top of the switch. The call-finder shown in Fig. 2 is a onecoordinate hunting - switch comprising a set of four brushes 101<a> &c., mounted on a rotatable carriage, which is set in motion by a clutch magnet 106 and stopped by a holding-magnet 110. The call-finder has no normal position but remains in the position in which it was last in service. The sequence switches used to control the call-finder and group selector, the connector, and the register controller are identical with that described in Specification 20,840/09, the clutch magnets of these switches being indicated by the reference nnmerals 105, Fig. 2, 505, Fig. 3, and 205, Fig. 4 respectively. The positions of the switches, in which the various contacts (except the contacts 111, 211, 511) are closed, are indicated by the numerals adjacent to the contacts. The contacts 111, 211, 511, which directly control the sequence switch motor magnets, are closed in all positions except those indicated by the adjacent numerals, which therefore indicate the positions in which the switch is capable of coming to rest. Construction of register - controller. Each register-controller consists of a number of ratchetdisks corresponding to the number of digits in the subscribers' numbers. Figs. 5, 6, 7, 8 show respectively the thousands, hundreds, tens, and units disks, which are fed forwards by the magnets r<1000> &c., responsive to the impulses sent by the subscribers, and are returned to normal or sub-normal positions by the magnets s<1000> &c. responsive to impulses sent back from the selector and connector. The pins U, U', U<2>, U4 close the contacts 189, 86, 153, 190 in their normal positions, and in addition the hundreds and units disks K1, K4 have additional contacts 85, 159, which are closed by the pins in their so-called sub-normal positions, these being necessary because the register-controller receives impulses on the decimal system but repeats them in modified number so as to control twohundred-point selectors and connectors. For this reason, the resetting-teeth m, m<1> of the thousands and hundreds disks have twice the pitch of the setting-teeth p, p<1>. The circuits of a registercontroller and its associated sequence switch are shown in Fig. 4. General operation of the system. When a subscriber calls, he is connected by a relay device to an idle register-controller, and a distributing- switch, associated with tbis, sets in action an idle call-finder which hunts for the calling line, while the register-controller is receiving the selecting- impulses. When these operations are completed, selection takes place in the group selector under the control.of the thousands and hundreds disks of the register-controller, and then in the connector under the control of the tens disk, which controls the brush chooser, and subsequently under the control of the hundreds and units disks. This joint control of the connector brush carriage is necessary because of the special wiring of the connector, in which the first ten terminals of each level correspond to the even hundreds of the particular 200-line group, while the second ten terminals correspond to the odd hundreds. Subscriber No. 1149, for example, would be connected to the nineteenth contact in the fourth level of the group of connectors serving the subscribers 1000- 1200. The operations, described in greater detail, are as follows. Connexion of calling line to idle registercontroller. Two or more register-controllers are provided for a number of subscribers' lines, each line having a number of relays such as 54, 55, Fig. 1, whereby it can be connected to the corresponding register-controller. If the first registercontroller, shown in Fig. 4, is idle, the excitation of the subscriber's line relay 53, Fig. 1, closes a circuit over its bottom contact through the coupling-relay 54, and sequence switch contact 57, Fig. 4. The relay 54 locks up over a circuit including the lower winding of a cut-off relay 52, contact 59, and a resistance 60, which prevents the excitation of the relay 52 at this stage. The relay 54 also completes a circuit through the meter magnet 63 and a second cut-off relay 51, which cuts off the line relay 53 and marks the test lead as busy. The meter 63 is not operated by this current. If the first register-controller had been busy, the circuit of the relay 54 would have been open at the contact 57, which in all positions of the sequence switch, except the first, prepares the circuit for the coupling-relay 55 of the second register-controller, so that the relay 55 would have been energized and would have locked up through the upper winding of the relay 52. Operation of register-controller by impulses sent by calling subscriber. The relay 54 also completes a circuit from the battery through the relay 68, Fig. 4, contact 67, wire 61, sub-station apparatus, wire 62, and through the relays 65, 66 to earth. The relay 65 moves the sequence switch into its second position, in which the magnet r<1000> of the thousands disk is connected to the front contact of the relay 66. The subscriber's impulsetransmitter intermittently grounds the b-line, thus short-circuiting the relays 65, 66, of which the relay 66 responds quickly and repeats the first set of impulses to the magnet r<1000>. After each set of impulses, the b-line is earthed for a sufficiently long period to allow the armature of the slowrelease relay 65 to move the sequence switch into its third position, and then, when the relay is again energized, into its fourth position, in which the hundreds magnet r<100> is connected to the relay 66. In the same way, the magnets r<10>, r<1> are actuated in the sixth and eighth positions. The long impulse after the last set of impulses moves the switch into its tenth position, and in passing through its ninth position, the resistance 60 is short-circuited, thus energizing the cut-off relay 52, which disconnects the subscribers' line until the selecting-operations have been completed. Selection of idle call-finder. As the registercontroller sequence switch moved into its second position, the contact 70 momentarily earthed the clutch magnet 305 of a distributing-switch, structurally resembling a sequence switch, which has pre-selected an idle call-finder. Assuming that the distributing switch was in its first position, it moves forward into its second position, and in doing so momentarily earths the lead 600, thus energizing the clutch magnet 105, Fig. 2, of the pre-selected finder sequence switch, and starting the hunting operation. The leads 600 of busy call-finders are earthed at the contact 74 so that the clutch magnet of the distributing-switch remains energized until the switch reaches the terminal of an idle callfinder, when the switch is arrested. Call-finder. The fourth terminals 104, Fig. 2, of non-calling and through-connected lines are earthed through their meters 63, so that when the finder sequence switch moves into its third position, the test relay 75 is energized, and completes the circuit of the motor magnet 106 which rotates the wipers 101<a> &c. until the test wiper 104<a> finds the calling line, whereupon the relay 75 de-energizes, disconnecting the motor magnet 106 and energizing the holding-magnet 110. The relay 75 also closes a fresh circuit for the clutch magnet 105, so that the sequence switch moves into its fifth position, in which the completion of the operation of the register-controller is awaited. Pending the disconnexion of the register - controller and the de-energizing of the relay 54, Fig. 1, the fourth terminal 104 is earthed over a contact 76 so as to prevent the calling line from being seized by another finder. During the time that the finder brushes are passing between the contacts, the testrelay 75 is kept energized over the finder interrupter 109. As the finder sequence switch moves into its fourth position, a contact 96 closes a fresh circuit for the cut-off relay 51, Fig. 1, so as to make this relay independent of the coupling-relay 54. Group selector. In the fifth position of the finder sequence switch, the relay 80, Fig. 2, is energized over contacts 81, 101, line a, sub-station apparatus, wire 62, and rela