Patent GB-191107611-A (GB)
Title: Improvements in and relating to Telephone Exchange Systems.
Inventor: CLEMENT EDWARD EDMUND
Filed: 1911-03-27
Granted: 1912-03-27
Abstract: 7611. Clement, E. E. March 27. Automatic and semiautomatic exchange systems.-The side switches usually associated with the selectors and connectors are dispensed with, the operations in the selector trunk circuits being controlled by master-relays, which are energized and cut off in succession in the order of operation of the successive switches. The invention is described in connexion with a semiautomatic system, and includes features which relate only to such systems. Other improvements of more general interest relate to the use of call-finders of two coordinate motion type, for connecting an idle firstselector trunk to a calling line; to the use of similar switches for connecting an idle operator's set to the appropriated first-selector trunk; and to partyline ringing- arrangements. The calling lines are divided into groups of 100, each group having a distributing-switch S, Fig. 2, which starts and controls the movement of an idle call-finder S<4>, Fig. 3, to connect a calling line to a first selector S<5>. There are ten firstselector trunks as shown in Fig. 3, alloted to each group of calling lines. A second distributing- switch S<2>, Fig. 2, simultaneously starts and partly controls the movement of a trunk-finding switch S<8>, Fig. 5, which connects an idle operator's key-set, Fig. 6, to the appropriated first-selector trunk, Fig. 3. A kick-off switch S', Fig. 2, prevents the calling line from being tied up by the failure of a defective finder-switch or trunk. The operator sends impulses to control the selector S<5>, which finds an idle second selector if the exchange is a very large one, or may fasten directly on the terminals of an idle connector, Fig. 4, serving the group of subscribers to which the wanted subscriber belongs. Further impulses are then forwarded to the connector trunk to select, by means of a switch S<7>, a ringing-generator corresponding to the position of the wanted subscriber on his party line, Fig. 7, and then to set the connector itself on the terminals of that line. The successive operations of the operator's key-set are controlled by a distributing-switch S<3>, Fig. 5. A fuller description of the operations is given in the following paragraphs. Seizure of idle first-selector trunk and operation of its call-finding switch S', Fig. 3. When subscriber A, Fig. 2, takes down his receiver, relays R', R<3> are energized in series and ground the test terminals c<25>, c<26> multipled in the banks of the callfinding switches. The relays R<3> and terminals c<26> belong to a group of ten lines, and control the first or rotary motion of the call-finder to bring its wipers opposite the vertical row of bank terminals corresponding to these ten lines. The relay R' and terminals c<25> are individual to the calling line and control the second or vertical motion of the callfinder. The relay R<3> energizes an indicating-lamp L and a starting-relay R<4>, which connects an interrupter I to the stepping-magnet M of a distributing switch S until the switch arm ws finds battery potential on the test-circuit 38 of an idle first-selector trunk, Fig. 3. A circuit is now closed through the relay R<5> (which locks up and cuts out the magnet M) and a master-relay R<13>, Fig. 3, which locks up and connects an interrupter I to the relay R<18> controlling the rotary magnet M<5>. The call-finder switch S<4> is rotated until the wiper w<26> comes into the grounded row-test contact c<26>, energizing the relay R<12>, which locks up and puts the interrupter I on to the relay R<19> controlling the vertical magnet M<6>. The switch S<4> is now stepped vertically until the wiper w<25> comes on to the grounded individual test contact c<25>, whereupon the relay R<15> is energized and cuts out relays R<12>, R<18>, R<19>. The de - energization of the relay R<12> completes a holding-circuit through the relay R<15>, wiper w<4>, trunk 4, and relay R<2>, Fig. 2. The relay R<2> connects the trunks 3, 4 to the calling line 1, 2, which is now supplied with current over the relays R<15>, R<14>, which remain alive until the release of the connexions. The battery-potential thus established on the multiple terminals c<4>, Fig. 2, guards the line from interference. Seizure of idle operator's trunk and connexion thereof to the appropriated first-selector trunk by the trunk-finding switch S<8>, Fig. 5. These operations proceed concurrently with the seizure of an idle first selector. When the relay R<5> is energized as described above, it energizes the relay R<11>, which connects an interrupter I to the stepping-magnet M<2> of a three-armed distributing-switch S<2>. When the switch arm ws<200> comes on to the test circuit 79 of an idle operator's set, Figs. 5 and 6, it receives battery-potential and completes a circuit in series through a relay R<10> (which energizes the relay R<9>, which locks up and cuts out the magnet M<2>) and through the master relay R<32>, Fig. 5, of the operator's circuits. The relay R<32> locks up and connects an interrupter I to the relay R<39> controlling the rotary magnet M<13> of the operator's trunkfinder S<8>, which is rotated until the wipers are opposite the vertical row of contacts belonging to the ten first selectors which serve the group of one hundred lines in which the call originated. The wiper w<82> is now on the contact s<82>, connected to the battery by the arm ws<20> of the distributing- switch s<2>, Fig. 2, and a circuit is closed through the relay R<31>, which locks up and transfers the interrupter I to the relay R<40> controlling the vertical magnet M<14>. The switch S<8> therefore steps up vertically until the wiper w<84> comes on to the contact s<84>, which has been connected to battery by the energization of the master relay R<13> of the switch S<4>, Fig. 3, whereupon a circuit is closed through the relay R<30>, which unlocks the relay R<32> and cuts out the relay R<40>. The operator's circuits are now connected by the switch S<8> with the occupied first-selector trunk, Fig. 3, and thereby with the calling line. As long as the switch S<8> remains in use, the foot switch F<8> lights the offnormal lamp L<7> and cuts off the battery from the test circuit 79, so that the operator tests busy to the distributing-switch S<2>. Release of distributing-switches S, S<2>, Fig. 2. The engagement of the wiper w<83>, Fig. 5, with the contact s<83> energizes in series the relays R<34>, Fig. 5, and R<42>, Fig. 3. This leads to the de-energization of relays R<5>, R<8>, R<9>, R<10>, R<11>, Fig. 2, and of the master-relay R", Fig. 3, and leaves the distributing- switches S, S<2> free to deal with the other calls on the group of lines with which they are associated. The energization of the relay R<42> also has the effect of cutting-off the calling line from the subsequent selecting-impulses. Automatic disengagement from defective operator's or selector trunks. A " kicking off " switch S', Fig. 2, slowly advanced by a stepping- magnet M<1>, has every fourth contact in its two contact-arcs multipled respectively to relays R<6>, R<7>, the remaining contacts being dead. The live contacts in one arc are one in advance of those in the other arc. After the relays R<8>, R<9> have been energized, the arm ws<10> coming on to a live contact energizes the relay R<7>, which locks up and closes a preparatory contact in the circuit of the relay R<6>. The switch S' must then take at least three steps before the arm ws<1> comes on to a live contact. This interval is sufficient for the complete operation of the first selector's and operator's finding- switches S<4>, S<8> and for the subsequent release of relays R<9> &c. as described above ; but if, owing to defective action of these switches &c., the relay R<9> is still energized when the arm ws<1> comes on to a live contact, a circuit is closed through the relay R<6>, which energizes the release magnets of the switches S<4>, S<8> and steps forward the switch S to find another first-selector trunk. Operator's signalling-arrangements and key-set. The relay R<34>, energized as described above, supplies current to the right alarm bell N and service meter E, Fig. 5, and to the guard lamp L<2> and line lamp L<3>, Fig. 6. The operator, perceiving the signal, presses her listening - key LK, Fig. 6, energizing the listening-relay R<33>, Fig. 5, which locks up, open - circuiting the relay R<34> (which extinguishes lamp L<3>) and relay R<42>, and connecting her telephone OR over the lines 130, 135 with the trunks 9, 10, Fig. 3. The lamp L<4>, Fig. 6, is energized in parallel with the relay R<33>. If the calling subscriber should have hung up his receiver, the relay R<14>, Fig. 3, will have been deenergized, and the actuation of the relay R<33> completes a circuit from the battery, Fig. 3, over the contacts of the relays R<15>, R", resistance r, trunks 7, 9, line 130, Figs. 3 and 5, wiper w<80>, trunk 131, contact of relay R<33>, through relay R<38>. to earth. Relay R<38> connects the tone-test Tt to the telephone OR, notifying the operator, who restores the circuits and switches in a manner described. Otherwise, the operator ascertains the number wanted and sets it up on her key-set, Fig. 6, depressing those keys in the rows K<1>, K<2>, K<3>, which correspond to the figures of the first, second, and third digits, and that key in the row K' which corresponds to the position of the subscriber wanted on his party line. For sending the appropriate number of impulses, the keys are multipled as shown in Fig. 6 to the contacts d<1>, d<2>, d<3>, &c. of a sending-machine, these contacts being closed periodically by rotary cams D<1>, D<2>, D<3> &c. during one, two, three, &c. contact closures of an interrupter I. By means of a distributing-switch S<3>, Fig. 5, the sets of impulses representing the different digits are successively forwarded to the selective switches over wires 130, 135. First selector S<5>, Fig. 3. Having se