US1603608A - Telephone-exchange system - Google Patents

Description

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w U U r @w I E S w a vi 0 E M M E KERR TELEPHONE EXCHANGE SYSTEM Fiid May 5, 1924 Oct. 19 1926.

n w% \w\ \Q tlhlil i so Mi-111K 1 1E313, O15 ROSEYBANK, NEW' YURI-i, ASSIGNOR T0 WESTERN ELECTRIC GOM- Pfirll'ii, 1N CORPORATED, OF Nlll/J "293.111,

ii, A CORLPOEATIGN 0? NEW YORK.

TELEPHONE-EXCHANGE SYSTEIVE.

Application filed May 5, 1924. Serial No. 711,040.

This invention relates to telephone exchange systems, and more especially to such systems as employ automatic switches in the establishment and completion of talking connections.

In inulti-oflice telephone systems, it is the usual practice to provide two wire trunks extending between the several exchanges. In effect, these interorlice trunks appear in contacts of so-called oliice selector switches at the calling oiiice, and. terminate in contacts of incoming selector switches at called ollices. When one of these trunk, is seized for the purpose of extending a calling line, provision is made for rendering it nonselectablc at the call ng oilice. ll hen connection has been completed over such a ti. ml; to a called line at a distant office, provision is also made for allowing both the calling and called subscribers to control the release of the said trunk. The invention is particularly applicable to such systems wherein the number of interor'lice incoming selector switches is less than the number of final se lector switches and wherein the called subscriber has supervision over the release of the incon'iing trunk.

Accordingly, it is the object of the invention to increase the efficiency of interoilice coninuuiication by allowing the release of an intero'll ice trunk to be controlled by a called subscriber, witi means for automatially and immediately releasing such trunk ilnlependently of the called subscriber, when the trunk is seized for the extension of a second calling line prior to disconnection by the said allcd subscriber.

A feature of the invention relates to the means for rendering an interollice trunk selectable for the purpose of con'ipleting a second conversational connection thercover before the complete release of a preceding first conversational connection.

linotlnsr feature relates to an interoliice incoming selector trunk which has an automatic timed release feature combined with an imn'iediate release feature, the latter being effective when the said incoming selector is seized for the purpose of extending a second calling line prior to disconnection by the previously called line.

Other inherent features and advantages may be ascertained after a consideration of the following detailed description of the operation of a particular application of the invention.

ll hile for the purpose of description it has been chosen to illustrate the invention as applied to an automatic telephone system wherein switches of the coordinate type are used, such as shown in the patent to C. L. Goodruln and J. N. Reynolds, No. 1,515,735 granted Nov. 18, 192%, it is understood that the invention in its broad aspects is not to be limited thereby. The invention may be as well applied to so called power drive systems and, in general, to any automatic telephone systen'i employing markers and wherein the selectable condition of an interoi'lice trunk is dependent upon disconnection by a called party.

The invention is described in connection with a telephone system such as disclosed in the copending application of Warren W. Carpenter, Serial No. 703,362, filed April 1, 1924.

Detailed desert 2050a.

Let it be assumed that the subscriber at station 101, whose telephone line is located. in oliice 100, has initiated a call for the purpose oi conversing with the subscriber at station 121, whose line is located in a distant otlice. In the manner described in detail in the patent to B. l i illiams and. E. Gibson, No. 1,543,967 granted June 30, 1925, the calling line 102 is extended by means of automatic switches in oliice 100 to an idle interofl ce trunk such as 108, the latter being innnediately rendered non-selectable at the oliice selector switch to other calling lines. The seizure of trunk 108 causes the operation of slow release relay 111 in through its left winding, upper armature and back contact of relay 128, upper left winding of repeating coil 121, tip conduc tor of the trunk, through apparatus in office 100, returning over the ringside of the trunk, through the left lower winding of repeating coil 121, lower inner armature and back contact of relay 128 to ground through the right winding of relay 111. Relay 111 extends ground through the upper inner armature and back cont-act of relay 103, left armature and contact of relay 111, left normal contacts of relay 123, sender selector start wire 122 to battery through the winda circuit traceable from battery.

ing of relay 11 The operation of relay 11 causes the actuation of sender selector switch to selectively ass ciate an idle incoming" sender as with the interolfice trunk. For the manner in which relay 112 causes the operation of switch 110, reference may be had to the patent to S. B. Williams and E. S. Gibson No. 1,543,967 granted June 30, 1025, and herein before referred to. As soon as an idle senoer has been connected, relay 103 operates, opening the circuit of relay 111 which releases. The tip and ring conductors of the incoming trunk are new extended to the receiving mechanism in the sender 12 and the sender at oiiiCe 100 transmits series of characteristic impulses to cause the called line designation to be re-' corded on the registers of sender 1 0. Vi hen relay 103 operated, ground was re moved from the start wire 122, and an obvious circuit was closed for the holding relay 123. The operation of clay 123 opens the sender selector starting circuit at a second point to prevent subsequent i'eoperation o relay 103, after completion of connection through switches 170 and 180. Relay 123 also connects ground through its right armature and contact, right normal contacts or" relay 132 to the sleeve conductor'ot trunk 10-1. l i hen the designation of the called line has been recorded in sender 120, connee-tor is actuated to connect the controlling marker to the sender. The marker 140 now functions to control the selective operation of incoming switch and final switch so to connect trunk 10-1 with the called line 190. For a detailed description of the manner in which these latter operations are eh ected, reference may be had to the application of ll arren W. Carpenter, Serial No. 703,362, filed April 1, 1924-.

When the foregoing connection of trunk 10% and line has been completed the sender selector switch 110, sender 120, connector 130, inarker 140, and the various connectors 150, 160, cte, are released and revert to common use. The release of the sender selector switch 110 causes the release of relay 103, thus completing; connection of the interol'lice trunk 1053 with the left windings of repeatingcoil 121., causing reoperation of relay 111. Relay 123 being slow to release does not retract its arinatures during: the interval between the release of relay 103 and the operation of relay 111. As soon as relay 111 reoperates, it provides a locking circuit for relay 123. This circuit may be traced from battery through the winding of relay 123, lower inner arn'iature and contact of relay 103, left outer armature and contact of relay 129, left armature and front contact of relay 123, left armature and contact of relay 111 "to ground at the upper inner armature and contact of relay 103. The reopv 10. w A. I aeiay rat, loner ()llti c.iniatuie and cow eration of relay 111 also extends this grounu over conductor 1%, conductor 1 armature and contact of relay 120, lower inner armature and contact of relay 125 to be tery through the winding oi ringing control relay 12 1. This ground is also erlcndcd by 1116:1118 of conductor 15 throi i the windi oi? relay which does not ope 'ate at this time since its vinding is shunted. 'llhe operation of relay 12lconiiects current from he ringing; source 153 through the winding ot relay 120, right arn'iature and contact ol" :tll of relay 125, ring conductor of trunk 104-, contacts oi switch 1T0, condactor of trunk 105, contacts or switch 180 through 1 me 1": 'nig apparatus at tne caller-i sub- SCIllJQlI'. station and return. thence through contacts or switch 180, tip conductor oi trunk 105, contacts of switch 170, tip cononctor of trunk 104-, upper outer armature and contact or' relay 1.25, to A ground at the left armature of rela ll hen the subscriber at station 121 removes the receiver from the sw'tchhoolr the resii-i ance of the above tra ed circuit throragn of relay 126 is reduced, and this relay operates. Relay 126 at arn'iarn 'e and contact removes the shunt from the winding of relay 125 which now operates to h grounded conductor 154;, thus extending the tip and ring coi'iduetors of tr right windings oi repeating CO1 crating sup visory relay 12. -4 closes an bvious operatingg' circuit to 128 which reverses the current in dnctors at t When the conversation to; the calling subscriber replaccs receiver upon the enritchhook, clay 111 release: The release of relay 111 renioves ground from the conductor 15-1, but it the called subscriber has not ll'iQEtIlWliilG replaced the receiver, relay 125 reinains operated in a circuit traceable from battery through its inding, conductor 15%, windin of rela y 120, left normal contacts of relay r82 to ground at the lower armature and contact of relay 2S. Relay 120 operates in this circuit and at its right inner armature and contact maintains a busy potential on the sleeve conductor of trunk 10 1-. hen interrupter 161 clos lower contact, ground is connected through the right outer arn'iature and contact of re lay 129, left normal contacts of relay 131 to battery tl'irougrh the winding 01 the same. Relay 131 looks through its winding and loclr'ng contact to ground at the right inner arn'iature of relay 129. Should the called. subscriber n'iaintain the receiver oil the switchhoolr indefinitely, the circuits are so arranged that alter a predetermined inter al cg'ulated by the time of closure of the upper and LALU

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contact of interrupter 161, the trunk 104, switches 170, 180 and associated apparatus are automatically released. lVhen therefore interrupter 161 closes its upper contac assuming that the called subscriber still ha the receiver off the switchhook, ground is connected through the right armature and contact of relay 131 to battery through the winding of release relay 132. Relay 132 locks through its winding, left armature and front contact to ground at the lower armature and contact of relay 128. Relay 132 at its left normal contacts opens the circuit for relays 129 and 125. These latter relays new release. Relay 125 severs the tip .and ring conductors of the incoming selector trunk, and relay 129 removes holding ground from the sleeve conductor. In the manner described in the above mentioned application of Warren Carpenter, Serial No. 708,362, filed April 1, 1924, removal of ground from the sleeve conductor of trunk 10 1 causes the release of the connection through switches 170 and 180. This severance of the connection causes the release of relay 127 which in turn causes the release of relay 128. The connection has thus been completely restored to normal following the closure of the upper contact of interrupter 161. From the foregoing description, it will be seen that provision is made for automatically releas ing, after a definite interval an interotlice incoming selector when the called party fails to disconnect following the termination of conversation.

Assume that a connection has been completed by means of trunk 108 to called line 190, and after the termination of conversation, the party at station 121 fails to replace the receiver upon the switchhook within the predetermined time. Under these conditions, should the trunk 198 be again seized by a selector switch in the ollice 100 during the ii'iterval between disconnection of a previous calling party and the closure of the upper contact of interrupter 161.the incoming sclector will be immediately disconnected from the previous called line and rendered available in extension of the second calling line.

In this case, relays 1.11, 125, 127, 128. and 129 are operated. hen therefore trunk 198 is seized by an office selector at this time, relay 111 will operate as hereinbefore described. The operation of relay 111 closes a circuit for release relay 132 which may be traced from battery through the winding thereof, left inner armature and contact of relay 129, left armature and contact of relay 111 to ground at the upper inner armature and contact of relay 103. The operation of relay 132 brings about the successive release of relays 125, 129, 127, 128 and switches 170, as before described. Thus, the incoming selector is immediately rendered selectable by a second calling line, even though the previous called party has failed to replace the receiver within the specified time.

What is claimed is:

1. In a telephone exchange system, a calling oliice, a called oilice, lines in said calling oliice, lines in said called OlllCG, a two-wire trunk for completing connections between lines in said calling office and lines in said called oltice, means at said called ollicc for maintaining said trunk in engagement with a called line after said trunk has been disengaged from the calling line. and means under control of said calling oliice for disengaging said trunk from said called line after said trunk has been disengaged from said calling line.

2. In a telephone exchange system, a calling office, a called office, lines in said calling otlice, lines in said called. oflice, a two-wire trunk for completing connections between lines in said calling otlice and lines in said called office, means at said called office for maintaining said trunk in engagement with '1 called line after said trunk has been disengaged from the calling line, and means located in said called ofiice under control of said calling oliice for disengaging said trunk from said called line after said trunk has been dis-engaged from said calling line.

3. In a telephone exchange system, calling lines, called lines, a two-wire trunk extend ing between said calling and said called lines, means for completing a connection from one of said calling lines over said trunk to a particular one of said called lines, means under control of said called line for naintaining said called line in engagement with said trunk, and means responsive to the extension of a second calling line to said trunk prior to disconnection ofsaid called line therefrom to cause a forced disconnection of said called line to immediately allow said trunk to be used in completing the connec tion of said second calling line to another or the same particular called line.

4-. In a telephone exchange system, calling lines, called lines, a selector trunk for extending one of said calling lines to a particular one of said called lines, means for preventing said selector trunk from completing other talking connections while either said calling or said called line is connected thereto, and means effective upon disconnection of said one of the calling lines and responsive to the extension of another of said calling lines prior to disconnection of said called line for causing a forced disconncction of said called line to thereby allow said trunk to extend said other calling line.

5; In a telephone exchange system, calling lines, called lines, a selector trunk for extending one of said calling lines to a particular one of said called lines, means for preventing said selector trunk from completing other talking connections while either said calling or said called line is connected thereto, means for forcing a release of said selector trunk when said calling line disconnects prior to disconnection by said called line, a timing ar nngementfor timing the actuation or said forcing means, and means ellective upon a second seizure of said selector trunk prior to disconnection by said called lin-e tor rendering; said timing arrangement ineffective and for causing an immediate torced release of said selector trunk.

(3. In a telephone exchange system, calling lines, called lines, a selector switch for extending; one of said calling lines to a particular one oi said called lines, means for preventing said selector switch "from releasing while either said calling or said called line is connected thereto, means for forcing; a release of said selector switch when said calling line disconnects prior to disconnection by said called line, a timing arrangement for timing the actuation of said forcinn; means, and means ell'ective upon a second seizure of said selector switch prior to disconnection by said called line for rendering;- s timing arrangement ineffective and for causing an immediate forced release of said selector switch.

'4". In a telephone exchange system, calling lines, called lines, a two-wire trunk for extending one of said calling lines to a particular one of said called lines, means for preventing}; said trunk from con'ipleting other talking); connections while either said calling or said called line is connected thereto, means for forcing a release of said trunk when said. calling line disconnects prior to disconnection by said called line, a a tin'iine; arrangement for timing the acluation of said forcing means, and means ellective upon a second seizure of said trunk prior to disconnection by said called line for rendering said timing arrangement ineli'ective and for causing an immediate. forced release of said trunk.

S. in a telephone exchange system, a calling line, a called line, a selector trunk for extending said calling line to said called line, a timing arrangement associable with said trunk, means responsive to disconnection by said calling line prior to disconnectien by said called line for rendering said timing arrangen'ient etlective to cause a'forced disconnection oi said called line from said selector trunk, and means ell'ecti-ve upon a second seizure of said selector trunk prior to disconnection by said called line for causing an in'nnediate iorced disconnection of said valled line from said selector trunk.

9. In a telephone exchange system, a calling line, a called lic, a selectorswitch for extending said callingline to said called line, a timing arrangement associable with said switch, means responsive to disconnection by said calling line prior to disconnection by said called line for rendering said timing arrangement eiiective to cause a forced disconnection of called line from said selector switch, and means cfl'ective upon a second seizure of said selector switch prior to disconnection by said called line for causing an immediate forced disconnection of said called line from said selector switch.

10.111 a telephone exchange system, a calling line, a c lled line, a selector trunk for completing connections between said calling; line and said called lines, a timing arrangement associable with said selector trunk, means responsive to disconnection by said calling line prior to disconnection by said called line for rendering said timing arrangement elli'ective to cause a forced release of said selector trunk, and means effective when said selector trunl'; is seized second time prior to disconnection by said called line for causing an immediate release of said selector trunk.

ll. In a telephone exchange system, a calling line, a called line, a two-wire trunk for conmleting connections between said calling line and said called lines, a timing arrangen'ient associated with said two-wire trunk, means responsive to disconnection by said calling line prior to isconnection by said called line for rendering said timingarrangement etl'ective to cause a forced release of said two-wire trunk, and means of tective when said two-wire trunk is seized a second time prior to disconnection by said called line for causing an immediate release of said twowire trunk.

In witness whereof, I hereunto subscribe my name this 29th day of April, A. D. 19%.

MARK B. KERR.

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