Patent GB-191001422-A (GB)
Title: Improvements in or relating to Telephone Systems.
Inventor: FALES EDWARD DANIEL
Filed: 1910-01-19
Granted: 1911-04-19
Abstract: 1422. Fales, E. D. Jan. 19.. Automatic and semi-automatic exchange systems. -Relates to exchange systems in which combined automatic and manual working is employed, particularly applicable to systems in which the automatic switches are controlled over complete metallic circuits, no grounds being used at the substations. The invention comprises (1) arrangements of cord-circuits for extending calls between automatic and manual subscribers, (2) arrangements of private branch exchanges and district offices in connexion with both automatic and manual exchanges, (3) combined automatic and manual exchanges, and (4) the insertion of a twowire repeater in a trunk leading from an automatic exchange to a district office. The invention is described in connexion with the hypothetical system shown in Figs: 1, 2, and 3, in which Fig. 1 represents the automatic section of an exchange, Fig. 2 the manual section of the same exchange, and Fig. 3 a distant manual exchange, numerous types of subscribers and of district offices and of private branch exchanges being shown. Connexion of subscribers whose lines terminate directly in the automatic section of the main exchange. A complete system for the interconnexion of these lines is fully described in the Specification, the action of the line switches and master switch being identical with that described in Specification 1419/10, while the first and second selectors and the connector operate in the same way as the corresponding instruments in the preceding abridgment 1421/10. District office arrangements. In the district office of which the station A<2>, Fig. 1, is a member, the subscribers' lines are (1) multipled to the contacts of one or more connectors F' connected through a repeater I to second selectors at the main exchange, and (2) connected to individual line switches C<5>, controlled by a master switch, whereby connexion is obtained with an idle trunk leading to a first selector D<1> at the main exchange. Fig. 6 shows the arrangement of the repeater associated with a trunk leading to the district office. When the wipers of the second selector engage the trunks 179, 181, the line relay 182 is energized, and (1) energizes a slowrelease relay 187 which earths the lead 180, thus maintaining the circuit of the release relays of the first and second selectors, and (2) bridges the coil y across the trunks 190, 191, thus completing the circuit of the line relay of the connector. The last two sets of selecting-impulses are thus repeated by the relay 182] over a metallic circuit to the line relay of the connector at the district office. In the district office of which the subscriber A<3>, Fig. 1, is a member, two groups of connectors F<2>, F<7> are provided, the connectors F<2> serving for calls through the main exchange, while the connector F<7> serves for local calls. The subscribers' lines terminate in line-switches C<6> through which connexion is extended either to the local connector F' or through the secondary switch C<7> to a selector at the main exchange. This arrangement is shown in further detail in Figs. 7 and 8. Assuming first that a connexion is desired through the main exchange, the removal of the subscribers' receiver causes his line switch C<6> to extend connexion to the trunk 528, 529 of the special connector F<7>, and the secondary switch C<7>. The operation of the switch C<6> causes the master switch H<2> to move on one step, and also completes the circuit of the line relay 516, Fig. 8, which (1) by closing a contact 520-521 bridges a relay 522 across the conductors 523, 524 leading to the secondary switch C<7>, so as to provide a holding-circuit for the line relay of the first selector with which the switch C<7>establishes connexion, (2) completes a circuit for the slow-release relay 527, extending from earth G", Fig. 7, wire 513, contact 517-519, relay 527, contacts 530-531,534-535 to the battery lead 21. The relay 527 in turn (1) earths the wire 515, establishing a circuit through the hold-on winding 514 of the line, switch C<6>, and (2) completes a circuit through a contact 543-544 for the operating-magnet 539 of the secondary switch C'. The magnet 539 establishes connexion with the trunks 525, 526, and at the same time opens the contact 543-544 in its energizing circuit. The relay 522 then energizes in series with the line relay of the distant selector, and closes a fresh circuit for the magnet 539 through the upper winding of a relay 532 which closes a locking-circuit through its lower winding, and also shifts the battery connexion to the relay 527 so that the latter is unaffected by a movement of the master switch H<3>. The opening of the contact 543-545 prevents the excitation of a relay 547, controlling the vertical magnet 548 of the connector F<7>, thus preventing the actuation of this connector until the secondary switch C<7> has been released, as explained later. The first set of selecting-impulses is repeated by the line relay 516, which opens the contact 520-521 in the circuit bridging the relay 522 across the trunk circuit. The relay 522 thus acts in synchronism with the line relay of the first selector, and in so doing intermittently closes the circuit of a slow-release relay 562, which disconnects the condensers 565, 566 from the trunk circuit, and short-circuits the lower winding of the relay 522, thus reducing the resistance in the trunk circuit to the main exchange. The additional sets of selecting-impulses are repeated similarly, and act in known manner on the second selector and connector. The method by which subscriber A<3> calls another subscriber A<24>, Fig. 1, in the same local group will now be explained. The subscribers in this group must have two numbers, one number by which they are known to all subscribers not in the particular group, and a different number by which they are known within the group. Although the number of subscribers in the group is less than one hundred, their local numbers have three digits ; for example, they may be numbered from 500 to 599, in which case the fifth row of contacts in the first selectors serving this group at the main exchange is dead, and when the first selector is raised and rotated into this level in the manner just explained, it, as well as the secondary switch C<7>, is released as follows. When the first selector has been raised to the fifth level, the side-switch passes into its second position, thus starting the rotary movement of the selector, but as all the contacts in this row are dead, the rotary movement is arrested at the first contact and the side-switch moves into its third position, the trunks 525, 526 being thus disconnected from the line relay of the first selector and connected to its dead wipers. The line and release relays of the first selector are thus both de-energized, and' bring about the release of the selector, while at the same time the relay 522 Fig. 8, also de-energizes, thus opening the contact 559-561 in the circuit of the magnet 539 so that the secondary switch C<7> is released. The relay 547 is energized by the closing of contact 543-545, with the result that the second set of selecting- impulses sent by the calling subscriber is repeated by the relay 516 over a circuit which passes from earth G<22>, Fig. 7, wire 513, contact 517, contact 575-576 of the relay 547, slow-release privatemagnet relay 577, vertical magnet 548, and sideswitch arm 578 to the battery lead. The connector is thus raised to the desired level, and after the last impulse, the private-magnet relay 577 opens the circuit of the private. magnet 581, thus moving the side-switch into its second position. The final set of selecting-impulses is then repeated by the relay 516 through the rotary magnet 582 and the private - magnet. relay 577, thus bringing the connector wipers on to the contacts of the desired line. If this line is disengaged the side-switch passes to the third position, the circuit of the ringing-relay 583 being closed over the side-switch arm 578, relay 583, contacts of relay 589, and an interrupter. The generator 585 is thus intermittently connected to line until the subscriber replies, when the back-bridge relay 586 is energized, and opens a short-circuit round the relay 589, which breaks the circuit of the ringing-relay 583. If the required subscriber is engaged, the side-switch is locked in its second position, the private magnet 581 being energized over a circuit including the side-switch arm 705 and a relay, which connects the busy generator Q to the calling line. When the calling subscriber replaces his receiver, the line relay 516 opens the circuit of the relay 527, thus restoring the line switch, and closes the circuit of the release-magnet 810 of the selector. In the district office L<8>, Fig. 3, of which the subscriber A<17> is a member, the subscribers' lines terminate in line switches at the district office, by which connexion is made in known manner with trunks which terminate in jacks in the answering- section of the manual board L<6>. The subscribers' lines are also multipled to the contacts of connectors F<9> by which incoming calls are received, the connectors being set by an operator at the branch exchange L<7> to which calls are extended from the boards L<4>, L<6>, as described later. Private branch exchanges connected to automatic section of main exchange. In the private branch exchange L, Fig. 1, of which the subscribers A', A<5>, A<6> are members, the trunks from the main exchange end in jacks, and the stations are connected to the main exchange or among themselves by means of cord circuits. Some of the stations may be provided with impulse-senders, and can then operate the selectors &c. at the main exchange, while other stations are purely manual, and connexion with subscribers on the main exchange must be effected by the local operator, who is provided with an impulse sender for this purpose. The out-