US2238235A - Automatic telephone system - Google Patents

Automatic telephone system Download PDF

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Publication number
US2238235A
US2238235A US218370A US21837038A US2238235A US 2238235 A US2238235 A US 2238235A US 218370 A US218370 A US 218370A US 21837038 A US21837038 A US 21837038A US 2238235 A US2238235 A US 2238235A
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United States
Prior art keywords
relay
contact
over
selector
line
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Expired - Lifetime
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US218370A
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English (en)
Inventor
Tatzl Hans
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Siemens and Halske AG
Siemens Corp
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Siemens Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/58—Arrangements for transferring received calls from one subscriber to another; Arrangements affording interim conversations between either the calling or the called party and a third party

Definitions

  • the present invention concerns a special wiper" for stopping the selector in free selection on a characterised set and avoiding disturbances by the passage of the lines of a subscriber over an engaged connection which is attained according to the invention in that for the set on which the selector is to set itself in free hunting a ow of current is produced over the speaking leads bywhich the direction of the feeding current of an engaged set is reversed and in this way a relay situated between the speaking leads in the exchange which relay only energises in this definite direction, is excited on obtaining the set characterised by the current reversal and carries out the stopping of the selector.
  • Figs. l and 2 an embodiment of the invention is shown, illustrating an oice system with call-lnder and line selector for making internal connections on the exchange selector for making incoming and outgoing selections.
  • the call finder, line selector and the exchange selector are considered as up-and-around selectors.
  • a group selector is also shown which is connected between the intermediate call finder and line selector in Fig. 1 ⁇ when a larger office system is concerned. If group selectors are present and if the number of neighbouring set subscribers which are authorised for exchange connections is greater than the capacity of an exchange selector a second exchange selector is connected parallel to the previous one.
  • the relay R is energised over: negative, winding I of relay R, contact It, loop of the set T'nl, contact 2t, positive.
  • the relay R operates its contacts over contact 31'.
  • the calling subscriber is characterised at the wiper c of the call finder AS.
  • Over contact 4r the contact-row of the call iinder AS is characterised in which the calling set is included.
  • Over contact 5r the following circuit is made: positive, resistance WI, contacts 51', Bt, lc, principal contact Bic, of the call iinder AS, relay RI, connecting point 5/6 contacts 911
  • relay RI4 the vertical magnet H of the call nder AS receives current over: positive, contact l3c, Ilitl, I5l, IEu, shaft contact Ilw of the call nder AS, vertical magnet H, negative.
  • the vertical magnet H lifts the call finder AS by one step.
  • the contact I8. is also closed and with it relay TI over: positive, contacts
  • the relay TI opens the contact Ilitl so that the circuit of the vertical magnet H is interrupted again.
  • the vertical magnet H opens the contact lith.
  • Relay Tl releases and over contact Idil the circuit for the vertical magnet H and relay TI continues until the following circuit is closed again.
  • the interplay between vertical magnet H and relay TI continues until the following circuit is over the contact level HS of the call finder AS: positive, contacts igt, 4r, topmost contact HS, contact 20H, winding II of relay U, negative.
  • the relay U energises, opens the contact lBu and stops the call nder AS thereby on the contact row reached.
  • ⁇ rotary magnet D is energised and turns the call finder AS by one step in the contact bank which has been reached.
  • the contact 23d is closed so the relay TI is energised over: positive, contacts 13o, 23d, winding I of relay Tl, negative.
  • Relay TI opens at contact Illtl the circuit for the rotary magnet D.
  • the rotary magnet D and the relay Tl act now as reciprocal interrupters until the following test circuit is made over the wiper c of the call finder AS: positive, contact 24M, winding I of relay C, winding I of relay U, wiper c of call iinder AS, contacts 31, winding II of relay R, contact 251' and 26t, relay T, negative.
  • relay R holds, furthermore the relays C and T are energised and through the opposite winding I of relays U the relay U is brought to release.
  • relay C By means of relay C the Contact l3c is opened and the circuit of the rotary magnet D and the relay Tl opens. The call nder AS is stopped. Through relay C there follows the switching through at the Contact 2'Ic and 28e.
  • Relay C interrupts the circuit for the relay Rl at the contact 'Ic. Relay Rl releases.
  • relay C2 For the relay C2 the following holding circuit is made: positive, winding II of relay Tl, connecting points 'I/8, winding II of relay C, contact 30o, connecting points 5/6, relay C2, contacts I l0c2, I I I x and I l2f, resistance W2, negative. In the previous circuit the relay Tl is not energised.
  • relay V releases so relay U2 is energised over: positive, contacts dlp, p, principal contact SIIC, of the line selector LW, contact 52c2, winding I of relay U2, shift contact 45111, contact 41m, 47p, vertical magnet H, negative.
  • the vertical magnet H is not operated- Through relay U2 the contacts 44122 is opened and the contact 53u2 closed.
  • the subscriber now sends out the second impulse series for setting the line selector LW on a denite contact on the row of contacts that has been reached.
  • the impulses are again undertaken by the relay Al and now transferred through the contact 43al on to the rotatry magnet D of the line selector LW.
  • the circuit for the rotary magnet D is as follows: positive, contact dlp, winding I of relay V, contacts 4202, 43al, 53u2, rotary magnet D, negative.
  • the contact 45u is opened and so the circuit over the winding I of relay U2 is interrupted,
  • the relay U2 holds over: positive, contact SM2, 55o, winding II of relay U2 negative.
  • the relay V rst releases and puts back Through the impulse its contacts to their rest position.
  • the contact 55o is opened, the relay U2 holds for a short time as a result of its release delay and the following circuit is thereby made: positive, contact E61/.2, 51e, windings I and II of relay P, contact 5802, relay PI, wiper c of line selector LW, conductor 59, contact llal, winding I of relay F connecting points l0/Il, top contact Blrk, relay HSA, negative.
  • Line 59 is not multipled, Over the line 59 a relay F arranged on the line selector LW alone is energised.
  • the subscriber of the calling set 'I'nl selects digits for setting the line selector LW
  • the arrangement can also be so constituted that after lifting the line selector LW to a deiinite row of contacts the contact, on which the line selector 59 is connected, is automatically selected.
  • the relays Pl, F and HSII are energised.
  • the relay PI closes the contact GZpl so Ithat the circuit over wiper c of the line selector LW is maintained independent of ⁇ the contacts 56u2, 51o and 58c2,
  • the relay U2 restores.
  • the relay PI opens 'the contacts 63pl, 64pl, 36pl, 3510I and closes the contacts Gpl, Spl.
  • the relay is also energised so that now the following circuit is made: positive, contact 29ml, winding II of relays AI, line Ii'I, contact 63, wiper b of line selector LW, contacts 691, pl, S'Itl, 21e, wiper a of the call nder AS, winding I of relay X, subscribers loop of subscribers line Tnl, winding II of relay X, wiper b of the call nder AS, contacts 38H, 66pl, 10f, Wiper a, of
  • the relay Anl is, therefore, energised by sending out of the exchange characterising digit.
  • the vertical magnet HI causes the lifting of the selector AW on to the first contact row-
  • the contact 92M is closed so that the relay V2 is energised: positive, contact 92M, windings II and I of relay V2, contact 89s, resistance W4, negative.
  • Relay V2 opens the Contact 82112 and interrupts thereby the circuit for the Vertical magnet HL
  • the Vertical magnet HI sets back the contact 9271A into its rest position again so that the circuit for the relay V2 is interrupted.
  • the relay V2 closes the contact 82112 so that the circuit for the vertical magnet HI is made again.
  • the interplay between the vertical magnet HI and the relay V2 acting as, mutual interrupters continues until over the Contact level 93hs of the exchange selector AW the contact characterised by contact 9417134 of ⁇ the relay HS4 is energised and the relay Ul is operated.
  • the circuit for the relay UI extends over: positive contact 94hs4, contact 95, bank contact 93hs, contact 96r2, windings I and II of relay UI, negative.
  • the relay UI sh0rtl AW negative.
  • the contact lldl is closed so that the relay V2 is energised over: positive, contact 88dl, winding II and I of relay V2, contact 89s, resistance W4, negative
  • the relay V2 energises and opens at the contact 82122 the circuit of the rotary magnet Dl.
  • the rotary magnet Dl sets back the contact Blldl to its rest position.
  • the relay V2 restores and there is closed again over contact 82122 the u circuit for the rotary magnet Dl.
  • the relay C4 of the lexchange selector energises in the previous circuit 5 ⁇ as a result of the current reversal after the carrying out of the digit selection for outgoing exchange connections.
  • the exchange selector AW is not stopped on an existing connection since at the existing connection an oppositely directed current flows over the speaking lead by which the relay C4 cannot be energised through the rectifier GR. No potential is situated on the moving wiper of the exchange selector AW so that a disturbing noise due to ruiming over an A,
  • the relay C4 lof the exchange selector AW energises and opens the contact 8604 and closes contact
  • the relay Al restores so that relay C2 is short-circuited over contact 90H.
  • the relay C2 sets back its Contact into its rest position.
  • the rotary magnet D of Athe call find-er AS receives current over: positive, contacts l3c, l4tl, ll3rl, raised contact 221C, rotary magnet D, negative.
  • the contact 23d is closed and thereupon relay Tl energises.
  • Relay Tl opens at contact
  • the rotary magnet D causes the release of the relay Tl by opening the contact 23d.
  • the interplay between relay T and rotary magnet D continues until the principal contact 22k is opened in .the rest position of the call finder AS.
  • the relay C3 of the selector AW energizes before the release of the relay C4 over positive, contact ll4c4, winding II of relay C3, contact llum, 266t1', Wiper cl of the exchange selector AW, line l I6, winding II of the relay R, Contact 251', relay Relay C3 holds the 4previous circuit independently of contact
  • the following feeding circuit for the calling station Tnl now exists over: negative, winding I of rel-ay S, winding I of relay X2, contacts le, ll8c3, wiper al of the exchange selector AW, line 99, loop of the set Tcl, line
  • the relay S is energized.
  • the relay X2 is considered as differential relay, By means of relay S the switching through of the exchange line over contact
  • the relay VI is energized over: positive, contact
  • the calling subscriber can now operate his dial for the purpose of setting the selectors which are reached over the exchange line AL and in this way causes the feeding bridge relay S to release impulsively.
  • the impulses are transferred through contact
  • the circuit for the relay V2 is prepared.
  • the impulses are sent out, by the first release of the relay S the short-circuit for the relay V2 is removed over contact l23s and the relay V2 is energized.
  • the relay V2 remains energized during the impulse series and short-circuits the windings III and IV of the transformer Ue over contact I3Ic2.
  • a group selector GW is inserted between the call finder and the line selector LW in Fig. 1 according to Fig. 3.
  • the connections result in that the connecting point I in Fig. 1 is connected to the connecting point l in Fig. 3, the connecting point 2 in Fig. l to connecting point 2 in Fig. 3, the connecting point 3 in Fig. 1 to connecting point 3 in Fig. 3, the connecting point 4 in Fig. 1 to connecting point 4 in Fig. 3, the connecting point 5 in Fig. 1 to connecting point 5 in Fig. 3, the connecting point 6 in Fig. 1 to connecting point 6 in Fig. 3, the connecting point 'l in Fig. 1 to connecting point 'I in Fig. 3, the connecting point Il in Fig. 1 to connecting point ll in Fig. 3.
  • the connection between l0 and Il in Fig. 1 is interrupted.
  • the relay Anl which is connected to the line selector LW is connected to the group selector GW in Fig. 3.
  • the group selector GW can be reached from a dennite group of subscribers and the dividing of the subscribers results in the first place in a group of subscribers which are connected at the wiper cl/bl/cl of the exchange selector AW (Fig. 2) and are reached over the contact series l, 3, 5, etc., of the group selector, while the other groups of subscribers are connected to the wipers a2/b2/c2 of the exchange selector AW and are reached over the directed contact row 2, 4, 6, etc., of the group selector.
  • the calling subcriber receives feeding current over: rest contact l33102,
  • the relay A2 opens the short-circuit for relay C2 at the contact If36a2.
  • the exchange characterizing is done by means of the relay A2 and transferred to the vertical magnet of the group selector GW which is not shown.
  • relay C in Fig. 1 and relay Cl in Fig. 3 are energized over contact lilcl.
  • the group selector GW rotates in known manner.
  • Relay Anl actually has the contact I35anl opened and thus disconnects the winding I of the relay Bl, the relay BI holds over: positive, winding 1I of relay BI, contact lllabl, wiper a of the group selector GW, contact M6122, connecting point I in Figs. 3 and 1, contact 3'Itl, 21o, wiper a of the call finder AS, winding I of relay X, loop of the set Tril, winding I of relay X, Wiper b of call nder AS, contact 28e, 33H, connecting point 3 in Figs. 1 and 3, contact I4'I1D2, wiper b of group selector GW, contact l48abl, resistance W6, negative.
  • relay R2 By means of relay Anl in Fig. 3 the contact Mani in Fig. 2 is closed, thus relay R2 energizes.
  • Relay R2 brings about in the previously described rnanner rst of all the operation of the vertical magnet Hl of the exchange selector (wiper set al to cl).
  • the rotary magnet DI is operated for setting on the contact of the contact row which has been reached.
  • the exchange selector AW reaches the contact of the calling set relay C4 is energized by the current reversal over the speaking leads.
  • the relay BI releases and opens the circuit for the relay P2 at contact l43bl.
  • the relay P2 restores and opens the contact I5Ip2 the holding circuit for the relay C in Fig. 1.
  • Relay C restores and effects the release of the call nder AS and over the Wiper cl of the exchange selector AW the locking circuit becomes effective.
  • the differential relay X2 is energized by the transitory operation of the key Tal.
  • relay Q is energized over: positive, contact IZ'IUS, l55r2, 2h32) winding I of relay Q, thermal relay Thi, negative.
  • Relay Q opens the short-circuit over the winding II of relay Q by means of its winding 1 of relay YI, contact
  • the series of discriminating relays consisting of relays I to IV is also controlled by the first impulse series for setting the group selector GW of the enquiry path.
  • the iirst release of the relay S by the impulse series brings up the relay I over: positive, contacts
  • the relay III is ⁇ energized over: positive, contacts
  • the relay III operates independently of the contacts
  • 991 is closed so that the relay II is energized over: positive, contacts IQZZI,
  • the relay II opens contact
  • the relays I and II hold over: positive, contact ISZzI,
  • ing circuit positive, contacts I92z
  • relay V2 restores, the relay IV is energized over, positive, contacts lvl, 2ll2r2, 203mm 204172, 205111, relay IV, negative.
  • the relay 1V holds over: positive, contacts
  • Relay IV opens the contact
  • a subscriber is concerned who is connected to an odd contact row of the group selector GW, the relays I and I1 are energized and characterized so that the subscriber called in enquiry is connected on the wipers al to CI of the exchange selector AW. ⁇
  • contact 2081 is opened and contact 2091 is closed. Further the Contact 2
  • the energizing of the relay R2 is prepared and thus alsothe setting of the exchange selector AW and the set of Wipers al/bI/.CL If, however, a called subscriber is concerned who is connected in an even contact row, the relays I and II are rested so that over Contact 2081 the energization of the relay R3 and thus the setting of the selector with its wipers a2/b2/c2 is prepared.
  • the relay P By the setting of the line selector LW on the speaking set over the wiper of the line selector LW only the relay P is energized.
  • the relay M Over the 5-second switch 5sac, contacts llu,
  • the calling circuit extends from the calling current source R., contact
  • the set T1L2 receives the feeding current circuit over contact I'I2nI.
  • the relay UM is energized by means of relay Q: positive, contacts 2
  • the relay UM operates and closes the contacts 261mm.
  • the following circuit is made: negative, resistance W8, contact 26mm, line
  • the relay F energizes.
  • the relay I-ISII is energized and characterizes the called set which is connected in the fourth contact row of the line selector LW and also in the fourth contact row of the exchange selector AW.
  • the relay AB closes the contact 2I1ab so that the winding I of the relay F is short-circuited, in this way a current reversal is prevented from occurring in a line selector after the characterizing digit; selection so that the controlled exchange selector AW can in no case be set on another subscriber than the one the characterizing digit has selected for the outgoing exchange connections.
  • the contact 2mal is opened by the relay AB in Figl 3 and the contact 2
  • the relay Anl is operated. Over contact 2I9ab and 226mm, however, the relay ABI is energized and in this way the contacts
  • the reversing exchange selector AW in Fig. 2 can in no case switch this on a calling subscriber who has selected the characterizing digit for outgoing exchange selections.
  • relay VI By the release of the relay S after the coming into effect of reversing impulses relay VI is shortcircuited over Contact
  • the rotary magnet DI of the exchange selector AW receives current over: positive, off-normal contact 223lcI, contacts 82122, 2321s, 8
  • the rotary magnet DI operates, steps the arms AI/b-I/cI of the exchange selector one step forward and closes contact dl. In this way relay V2 is energized.
  • Relay V2 opens the Contact 881.22 so that the circuit of the rotary magnet DI is interrupted.
  • the interplay between rotary magnet DI and relay V2 which interrupt each other follows until the exchange selector AW has reached its rest position in which the principal contacts 223m and 8'IkI are opened. If the selector is with its wiper aI /bI /cI in their rest position then the shaft contacts are also set back to their rest position.
  • the subscriber calling in enquiry is a subscriber who is reached over an odd Contact row of the group selector GW.
  • the circuit for relay R2 is prepared over contact 2891. Vv'hen, however, the exchange selector AW has reached the rest position the following circuit for the relay R2 is made: positive, contacts
  • the relay R2 is energized.
  • the following circuit for the vertical magnet HI is now made: positive, contact 8012, 82112, 830s, T912 88M, Contact 9910, SUwI. contact BITS, vertical magnet HI, negative.
  • the vertical magnet I-II works together with relay V2 (over contact 92M) as an interrupter until the following circuit is made by contact characterizing the relay HSII associated with the bank contact of the relay UI positive, contact 94h54, bank contact 93m, contact 9612, windings I and II of relay UI, negative.
  • Relay UI closes contact 9'IuI so that the relay UI has a delayed release.
  • the circuit of the rotary magnet HI is interrupted.
  • the relay C4 operates, so that by the opening of the contact 8604 the rotary magnet DI is stopped.
  • the relay CII effects repeatedly the transitory earthing of the lead 224 vso that the relay Y in the line selector is short-circuited and released.
  • Relay Y interrupts the circuit over winding I of the relay Z by opening the contact
  • Relay Z still holds over winding II.
  • Relay C2 restores and brings about in the described manner the release of the line selector LW of the group selector GW and of the call finder AS which has set itself on the enquiring line.
  • the locking circuit over wiper CI of the exchange selector LW is made, in which the relay C3 is energized.
  • the relay C3 causes the switching through of the exchange lead at the contacts I I 8c3 and
  • the relay S is energized again and over contact
  • the selector called in enquiry is connected by the reversal of the exchange selector AW with the exchange lead AL.
  • the series of leads I, II, III and IV is also used to characterize the exchange selector over which the subscriber desired by the exchange is obtained by incoming exchange connections.
  • B-y incoming exchange calls the relay AR is energized over the rest contact 228111. Over positive, resistance W9, contact 229m" winding I of relay H3, negative, the relay H3 is energized.
  • Relay H3 holds over: positive, contacts
  • the calling lamp ALI is lit up over: positive, contacts 236m, 23H1, lamp ALI, negative.
  • the operator takes up the receiver and operates the exchange key connected with the calling exchange line.
  • the relay AS is energized.
  • the relay AS holds over contact 233cm.
  • the apparatus BA is connected over contacts 238113 and 239113 to the calling exchange line.
  • the operator can discover the desired local subscriber from the calling subscriber.
  • the operator operates the connecting key ZIIIIVT.
  • the relay VS is energized over contact 24hrs.
  • Relay VS holds independently of the key VT over contact 242115'.
  • Relay VS opens contact 238115' and 2350s and closes the contacts 243118 and 21mm.
  • the apparatus BA is connected to the connection side of the exchange line and energizes the relay S.
  • the relay S brings about the energizing of the relay VI by closing contact
  • the holding circuit of the relay H3 is interrupted and the relay B is energized.
  • Relay B holds over contact I29l1.
  • the operator now sends the rst impulse series for the desired subscriber.
  • the first impulse series is taken up by the relay S and transferred to the series of relays I, II, III, IV and the relay I is energized by the first interruption over positive, contacts 241118,
  • Relay I closes the contact
  • the next impulseseries is now transferred by an odd rst impulse series over: positive, contacts 241215,
  • the wipers cI/hI/cI of the exchange selector AW are lifted to a definite contact row. If at the end of the second impulse series the relay V2 restores, the relay UI is energized over: positive, off-normal contact 223m, contacts 82111, 248118, shaft contact 2501112, 25
  • the contact Etui is opened and the contact 98u
  • the next impulse series is transferred to the rotary magnet DI.
  • the relay UI is maintained energized, however, over: positive, principal contacts 223Vcl, 252112, 255ml, Winding III of relay UI, negative, during the last impulse series.
  • the relay V2 first releases and relay E is energized over: positive, principal contact 223lcI, Contact 82112, 248115, 286111I, 259m, winding I of relay E, negative.
  • Parallel to' relay El the relay H3 is energized. The relays E and H3 hold independently of the contact 259m over contact 258e.
  • relay C3 of the exchange selector AW By means of relay C3 of the exchange selector AW the call circuit is closed over the calling current source, winding II of the relay E1, contact 255e, H803, Wiper al of the exchange selector AW, line 99, bell of the set Tnl, line
  • the subscriber replies the reverse winding II of relay E ⁇ becomes eifectivein the calling circuit.
  • Relay E restores.
  • the hold circuit for the winding I of the relay E is interrupted, since the relay UI is already released after the release of the relay V2 and the holding circuit is opened at the contact 25Std.
  • the circuit for the relay R3 is closed by even impulse series over: positive, contacts 282115, 28H, 2BIIIV, winding I of relay R3, negative, when at the end of the first the relay V 2 has released and relay IV has been energized.
  • the contact 9Ir3 is opened and the contact 2%13 is closed.
  • the next impulse series is transferred to the vertical magnet H2 and thus lifts the wipers a2/b2/c2 of the exchange selector AW to a definite contact row.
  • Ofi-normal contacts 285lc2 is closed so that the next impulse series effects the rotary magnet D2.
  • the selectors which have been used are thus set back in their rest positions.
  • a relay in a switching system, a relay, a plurality of lines each having two conductors, means for connecting a potential across the conductors of any one of said lines, a switch operative responsive to the connection of said potential across said one line to connect said relay across the conductors of said lines successively, said potential effete to operate said relay responsive to the connection of the relay across the conductors of said one line, and means including said relay for terminating the operation of said switch responsive to said operation of the relay.
  • a switching system a plurality of lines each having two conductors, means for connecting diierent potentials across the conductors of different ones of said lines, a switch, a testing device in said switch, means for operating said switch to connect said device across the conductors of said lines successively, said device responsive to only a predetermined one of said diierent potentials, and means controlled by said device for halting operation of said switch responsive to the operation of the device.
  • a switching system a plurality of lines each having two conductors, means for connecting a potential of predetermined polarity across the conductors of diierent ones of said lines at diiferent times, a plurality of switches, means for operating a switch to hunt for and extend a connection to each of said lines when said potential is connected thereacross, a polarized relay in each switch connected across the conductors of said lines successively during the hunting of that switch for a line having said potential connected thereacross, said relay operated responsive to the connection of same across the conductors of the line having the potential connected thereacross and effective to halt the operation of said switch, and means including said relay for then disconnecting said potential from the line and connecting thereto a potential of the opposite polarity, thereby to prevent subsequently operated ones of said switches from being halted on that line.
  • a switching system a plurality of lines each having two conductors, a potential of predetermined polarity connected across each of said lines, means operated to disconnect said potential from any one of said lines and to connect thereacross potential of the opposite polarity, a switch then operative to hunt for said one line, a polarized device connected across the conductors of each of said lines in turn during the hunting of said switch, said device responsive only to said potential of the oppositepolarity and effective to cause said switch to seize said one line.
  • a switching system as claimed in claim 4, wherein said device comprises a bridge containing a relay and a rectifier connected in series.
  • a relay a plurality of lines each having two conductors, a potential of predetermined polarity normally connected across each of said lines, means operated to disconnect said potential from any one of said lines and to connect thereacross a potential of the opposite polarity, a switch operative responsive to said operation of said last means to connect said relay across the conductors of said lines successively, said potential of the opposite polarity effectve to operate said relay responsive to the connection thereof across the conductors of said one line, and means including said relay for halting the operation of said switch responsive to said operation of the relay.
  • a relay in a switching system, a relay, a plurality of lines each having two conductors, a potential of predetermined polarity normally connected across each of said lines, means operated to disconnect said potential from any one of said lines and to connect thereacross a potential of the opposite polarity, a switch operative responsive to said operation of said last means to connect said relay across the conductors of said lines successively, said potential of the opposite polarity effective to operate said relay responsive to the connection thereof across the conductors of said one line, and means including said relay for restoring the potential across said one line to normal responsive to said operation of the relay.
  • a primary speech path a plurality of secondary speech paths, means for impressing a potential upon any one of said secondary speech paths, a switch terminating said primary speech path thereafter operative to search for said one secondary speech path and to connect thereto said primary speech path, a discriminating device in said switch connected to each secondary speech path in turn during said hunting of said switch, said potential eiective to operate said device responsive to the connection of said device to said one speech path, and means controlled by said device for halting the operation of said switch responsive to said operation of the device.
  • a telephone system a plurality of speech paths, a potential of predetermined polarity impressed on each one of said speech paths engaged in a call, means operated to initiate a call over any other one of said speech paths, a potential of the opposite polarity impressed upon said last speech path responsive to said operation of said means, a switch operative to search for said last speech path to extend a connection therefrom, a discriminating device in said switch connected to said plurality of speech paths successively during said search and responsive only to said potential of the opposite polarity to cause said switch to seize said last speech path.
  • a primary speech path a plurality of secondary speech paths, a potential of predetermined polarity normally impressed upon each of said secondary paths, means operated to remove said potential from any one of said secondary paths and to impress thereupon a potential of the opposite polarity, a switch terminating said primary path thereafter operative to search for said one secondary path and to connect thereto said primary path, a relay in said switch connected to said secondary paths successively during said hunting of the switch, said potential of the opposite polarity only effective to operate said relay responsive to the connection of said relay to said one secondary path, and means including said relay for terminating the operation of said switch responsive to said operation of the relay.
  • a primary speech path a plurality of secondary speech paths, a potential of predetermined polarity normally impressed upon each of said secondary paths, means operated to remove said potential from any one of said secondary paths and to impress thereupon a potential of the opposite polarity, a switch terminating said primary path thereafter operative to search for said one secondary path and to connect thereto said primary path, a relay in said switch connected to said secondary paths successively during said hunting ⁇ of the switch, said potential of the opposite polarity only effective to operate said relay responsive to the connection of said relay to said one secondary path, and means including said relay for terminating the operation of said switch and for restoring the potential across said one line to normal responsive to said operation of the relay.
  • subscribers lines In a telephone exchange, subscribers lines, switching apparatus, means for seizing said apparatus over any of said lines to extend either a local or an outgoing call, means in said apparatus for normally feeding talking current over the calling line in a particular direction, and means operated over the calling line only if said apparatus is seized to extend an outgoing call to cause said current to be fed over the calling line in the opposite direction.
  • subscribers lines In a telephone exchange, subscribers lines, a special line, an automatic switch having access to said lines, means for seizing said switch over any of said subscribers lines and for operating same either to extend ⁇ a call to any other one of said subscribers lines or to connect with said special line, a battery feed bridge in said switch supplying current in a particular direction to the calling line if the call is extended to another of said subscribers lines, means for rendering said bridge ineffective if said special line is connected with, and a battery feed bridge in said special line effective if said special line is connected with to supply current in the opposite direction to said calling line.
  • an exchange subscribers lines terminating in the exchange, a potential of predetermined polarity connected across each of said lines when that line is engaged in a call, a trunk outgoing from the exchange, means operated by a subscriber over any o-ne of said lines' to initiate an outgoing call, means for connecting a potential of the opposite polarity across said one line responsive to said operation of said last means, a switch terminating said trunk line operative to hunt for said one line and to connect thereto said trunk line, a discriminating device in said switch connected across each of said lines in turn during said hunting of the switch, said potential of the opposite polarity effective to operate said device responsive to the connection of said device to said one line, and means controlled by said device for terminating the operation of said switch responsive to said operation of said device.
  • a local switch train including a local switch, means responsive to a call from said line for extending a connection therefrom to s-aid switch, another switch having access to said line, means for operating said local switch over said line in response to the transmission of La particular digit, means responsive to said operation of said switch to change the potential across said calling line and cause said other switch to hunt for said line, said other switch responsive to said changed potential to seize said line.
  • a line having a particular potential connected across the line conductors thereof, a local switch, a iinder switch responsive to a call from said line for extending a connection therefrom to said local switch, means for operating said local switch over said line in response to the transmission of a particular digit, another switch having access to said line, means operated over a wiper of said finder switch responsive to said operation of said local switch and eiective both to change the potential across said calling line and to cause said other switch to hunt for said line, said other switch responsive to said changed potential to seize said line.
  • a plurality of lines a plurality of local switch trains common to said lines and each including a local switch, another switch having access to said lines, means responsive to a call from any one of said lines for extending a connection therefrom to one oi said local switches, a particular potential connected across the line conductors of the calling line, means for operating said one switch over the calling line in response to a particular digit, means individual to said one switch and operated over a wiper thereof responsive to said operation of said switch to change the potential across said calling line and cause said other switch to hunt for said line, said other switch responsive to said changed potential to seize the calling line.
  • a local switch train including a local switch, means responsive to a call from one of said lines for extending a connection therefrom to said local switch, a particular potential connected across the line conductors of the calling line, means for operating said local switch over said calling line in response to the transmission of a particular digit, means responsive to said operation of said local switch to change the potential across said calling line and cause that one of said plurality of switches having access to said calling line to hunt for said calling line, said one switch responsive to said changed potential to seize said calling line.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
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US218370A 1937-07-14 1938-07-09 Automatic telephone system Expired - Lifetime US2238235A (en)

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DE972989C (de) * 1954-05-05 1959-11-26 Kabelindustrie Ag Personensucheinrichtung
DE969905C (de) * 1955-05-24 1958-08-07 Telefonbau & Normalzeit Gmbh Schaltungsanordnung fuer Fernsprechnebenstellenanlagen mit in zwei Einstellbewegungen fortschaltbaren Amtswaehlern

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DE695154C (en)) 1940-07-18

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