US1688451A - Telephone signaling system - Google Patents

Description

Oct. 23, 1928.

C. S. DEMAREST El' AL TELEPHONE SIGNALINQ sYsTsu Filed may 19. 192s 3.2. Sgm

A TTORNE Y Asignals over the telephone circuits.

Patented Octo 23, 1928.

...taire STATES PAT E Nfr or F11-CE..

CHARLESL s. nnlvreniiszr; or, ninefnwoon, vNava.inrisriv., Aim; owen romans c; p

BnooKLYn, NEW. YQRKS assienoas'ro inwinneni;v TELEPHQHE NQ TELEGRPH ooivrrANY, A ooRroRATioii on NEW YORK. Y

TELEPHONE seNALrNs s'ifs'rnivi.

Application led May 19,

This invention relates to telephone signaling systems, andV more particularly to arrangements r'or transmitting supervisory signals between central oiiice stations.

ln, the` operation of' a group o'l telephone circuits by improved traflic method@ anumber oi supervisory signals are required.` Facilities for the transmission offtliese supe-rvisory signals are sometimes not available, as inthe case of radio speechchannels; anch-in the case. or ivire circuits, they cannot always be obtained unless there are sacriiiced facilities i'or the transmission of lrorse telegraph Furthermore7 with the present standard facilities for signaling over voice circuits, certain precautions must be taken in order to guard against interference with the signals bythe voice currents and' in order to reduce the -i-nterference Jfrom other voice circuits and the interference caused 'in= other voice circuits.

It is the object ofapplicants7 invention'to transmit supervisory `signals in cases in Which the facilities 'cannot loe obtained by Wire means, as in the' case 'of radio speech channels; and, in the case of Wire cir-cuits; to transmit such signalfsjivithout-any sacrilice oi" Morsetelegraph facilities andi Without any of the types of interference mentioned above.

Applicants accomplish this fobject by trans-l mitting all the supervisory signals for-Ia.

group of voice circuits over a common radio channel between the central oliice stations.

rflic arrangement described below and illustrated diagrainmatically in thel accompanying' drawing is one suitable for transmitting by applicants means the signals'employed inthe so-called fring down77 method otoperation, in which the central oiiice operators plug into and ring over thecircuits also used for the subscribers" conversation. l

lNith reference to the accompanying drawing, station A is a teleplione central o?" ce station connected with a distantcentral oiice station B by a plurality of'v-oice channels, Which-may be ordinary Wire circuits, carrier circuits7 or radio channels. yhesystem is shown equipped for operation in citherdirect-ion,y that for the initiation of a call at either station and the proper signaling` and supervision at both stations. The apparatus at each station consists essentially of radio transmittini7 means7 radio receiving 1926. [serial No. 110,249.

*means and the following in association with each` oi the voice channels; means for lpro-r ducingradio signaling Acurrentl for tjansmission7 nicans'ior suitablytuning the rcceivin-gv means; the usual annunciator, and meansfor associating the signaling current producerand the annunciator'with the rad-ioy transmitting and receiving apparatus7V respect'ively.A VFor-.each voice channel served and the receiver atv the otherv station beingl v correspondinglytuned by the circuit associated with that channel. Itl is to be understood that only the apparatus associatedavith one voice channel is shown in full, the apparatus peculiarly associated `withl 'the other channels being merely indicated and; its con-` nection to the radio transmitting andreceiving apparatus shown. y i

rlhe details off the-'signaling' system ivillbe clearly understood? .from the following description of` the operation thereof'. s

If a subscriber directly vconnected With the cent1-al o iice station'A Wishes to communicate WithY a, subscriber connected' With the distant central-office station Bytlie operatorv atV stati/'011A plfu'gs theftol-l cordinto jack J. Battery from the' sleeve of the toll cord operates relay Cj The operator then' rings,

.the ringing current beingrrrapplied over the leads T land R' to relay D, which operates. The relay D, upon operation, in` turn operates relay E. Theoperation of relay E connects 'the oscillator' Of, Whichl'produces high frequency si-gnalingfcurrena through the'tunedcircuit Fassociated with the voice channel under consideration 'and through the common ampliiier G tothe radio transmitting antenna .of station A. At the distantst'atiou B a-.ra'dio signal is received in the receivingV antenna, is changed"r in fre-f quenc'y (an oscillatorv` being associated vWith the PF-reque'ncy changer), *andy 1s passedlooks through its `lovver Winding.V The locking circuitof the relay includes the lamp LQ whichr is" associatedY With the jack JA.

` through thecommon amplifier H, the .tuned i Therefore, when the locking circuit of the relay is closed, this lamp lights. In response to the operation of the lamp L, the operator at station B plugs the toll cord into the j ack J. Battery fromV the sleeve of the toll cord operates relay C. Upon the operation of this relay the locking circuit ofv relay N is broken, relay N is released, and lamp L is extinguished.

If'the operator at station A rei-ings, the ringing current over leads 'l and R reoperates relay D, and a second radio signalv is transmitted to station B in the mannei described above. Relay N at station B again responds, but, since relay C remains operated, the lame L Will not light again, but relay P Will lie operated, the circuit to this relay beingV through the malte Contact` of relaypC. The operation of relay P connects to the leads T and R the current sourceand ground indicated in the drawing, and consequently ringing current is trans# mitted over these leads to the toll cord previously inserted in the jack J. As is Well understood in the art this ringing current operates an alternating current relay, which,

in turn, lights the supervisory lamp in the.

toll cord.` n

Only vso much of the toll cord circuitcateach station is shown as appears to be necessary to a full understanding ofr appli- ,cants invention.

' theleads T and R to relay D", which oper ates. rIfhe operation of this relay operates, in turn, relay E.' The operation of relay E connects the oscillator O, which produces high frequency signaling current, through the tuned circuit 15; and the common amplilier G to the radio transmitting antenna of station B. At the distant station A, the radio signal is received in the receiving antenna, is changed in frequency and is passed through a common amplifier H, the tuned circuit K, and the rectifier M to the relay,V N. Relay N` operates and locks through its upper Winding. The locking circuit includes the lamp L. associated `with the jack J. Accordingly, when the locking circuit is completed,v this lamp lights, giving the signal to the operator at station A, Who responds by plugging the toll cord 'int-o jaclrJ. Battery from the sleeve of the tollfcord operates relay C, its operation breaking the locking circuit `of relay N and extinguishing the lamp L. if

the operator at station B rerings, ringing current is again transmitted over the leads T. and R, and relay D is again operated.

rlhe re-operation of relay D results in the transmission of a second radio signal to sta-` tion A, and relay N again responds. Since relay C remains operated, lampr L Will vnot relight, but relay P vvill be operated, the

circuit to this relay being completed at thev make contart ofrelay C. The operation of relay l) connects to the lea-ds T and R the current source and ground indicated in the drawing, and ringing current is transmitted over these leads to the toll cord previously r inserted lin the jack J. c Nhileapplicants invention has been described in one specific embodiment which is deemed desirable, it is to be understood that it is capableof embodiment in many other and different` forms Without a departure from the scope of the invention as defined in the appended claims.

TWhat is claimed is: l. In a telephone system,

connecting said stations, means at each station for transmitting radiosignals,means at each station for receiving radio signals, and at each station in association Witheacli voice channel Ithe following :signal announcing means, means for producing signaling current peculiar in frequency to that station station, and automatic means for operating lie'si'gnal announcing means at that station in response to radio signals the other station.

2. In a telephonevsystem including ttvo tivo central otiice stations, a plurality of voice channels received fromA central oiice stations anda voizechannelV connecting said stations, means at each sta.- tion for generating and transn'ntting radio signals, means at each station for receiving the radio signals transmitted from the yother station, an annunciator at each station, lautomatic means at each station, responsive t0- ringing cu 1rent introduced into thevoiceV channel at that station, for operating the signal generating and. transmitting vmeans at that station, automatic means ateach station for operatingthe annunciator at that station in response Vto an initial radio sigllt) nal received from the other station, and automatic-means at each station for producp ing ringing Vcurrent at thatstation in re spense to a subseqent radio signal received frein the other station.

In, a telephone system includingV tivo ycentral ofiice ystations and a voice channel connecting said stations, means at each station for generating andrtransmitting radiov signals,means at each station for receivingV the radio signals transmitted from the other station, an annunciator at each station, automati'c means at each station, responsive to ringing current introduced into the voice channelat that station, for operating the signal generating; andftransmitting means at that station, automatic means lat each station for operating the annunciator at that.

station in response to an initial radio signal received froin'the other station, automatic means at each station for producing ringing subsequent radio signal received from the' other station. Y n n e'. lu 'a telephone system including two central otice stations and' aplurality oflvoice channels connecting said stations, means at each station for transmittingV radio signals, means at each station for receiving radio signals, and ateach station in association with each voice channel the following: means for fixing the frequency of the radio signals transmittedfrom that station at a value peculiar tothat station and to that voice channel,A means for tuning theV signal receiving means at that station to the peculiar frequency Y of the radio signals transmitted from the other station and corresponding to that voice channel, an annunciator, automatic means, responsive to ringing current introduced'into that voice channel at that station, for operating the signal transmitting means at that station, automatic means for operatingvthe annunciator at that station in response to an initial radio signal, of the predetermined frequency, received from the otherstation, and automatic means for producing ringing Cur-Y rent at that station inresponse to a suhsequent radio signal, of the predetermined frequency, received from the other station.

5. ln a telephone systemrincluding two central office stations and a plurality of voice channels connecting said stations, means at each station for transmitting radio signals, means at each station for receiving radio signals, and ateach station in association with each voice channel the following:

means for fixing the frequency of the radio signals transmitted from that station at a value peculiar to that station and to that voice channel, meansA for tuning the signal receiving vmeans aty thatv station to the peculiar frequency of ythe Vradio signals ltransmitted from the other station and corresponding to that voice channel, an annunciator, automatic means, responsive to ringing current introduced into that voice channel at that station,'for operating the signal transmitting means at that station7 automatic means for operating the annunciator at:- that sta-tion in response to an'finitia-ll radio signal, of the predetermined frequency, received from the other station,

automatic means for producing ringing cur-` rent at that station in responsev to a 'suhseque-I'it-radioI signal', of the predetermined frequency, received from the other station, and' automatic means for preventing the reopera-tion of the ann-unciator: at'that sta-tion in response to said subsequent radio signal received from the other station. f

In a telephone system ineIud-ingtWO- centraloilice stations and a plurality of voicechannels connecting'said stations, means at' ea'ch.. station'for transmitting rad-io signals,

moan-s ateach station for receiving radio' an annuncia-tor, automatic means, responsiveA to ringing current introduced into that voicer` channel atr that station, for connecting saidl current producingmeans'to the radio signal transmitting means Vat that station, auton matic means for operating the annunciator at that station in response to an initial radio signal, of the predetermined frequency, re ceived from the other station, and automatic means for producing ringing currentat that station in response to a subsequent radio signal, of the predetermined frequency, received from the other station. f Y

7. In a telephone system including two central oflice stations and a pluralityl of voice channels connecting said stations, means at `each station for transmitting radio signals,

means at each station for. receiving radio signals, and atk each station in .association with each voice channel the following: means for` producing signaling current kof a frequency peculiar to. that station and/to'that voice channel, means for tuning the'signal receivingmeans at that station to the peculiar frequency produced at the other station'and corresponding to that voice chan nel, an annunciator, automatic means, responsive to ringingv current introduced into that voice channel at that station, for connecting said current producing'means to the radio signal transmitting means atthat station, automatic means for operating/the annunciator atthat station in response to an initial radio signal, of the'predetermined frequency, received from the other station,`

automatic means for producing ringing curquent radio signal, of thev predetermined frequency, received from the other station, and` automatic means for preventing the re-operation of the annunciator at the station in rerent at that station in response, to a subsesponse to said subsequent radio signal received from the other station. y

t 8. In a. telephone system, a sending station, a receiving station, a voice channel connecting said stations and including a. line circuit and a cord circuit, adapted to be interconnected, at each station and a transmitting medium, a signal annunciator and` a line source of ringing current at the receiving stas tion, means at the sending station for generating and transmittingI radio signals, means at the receiving station for receiving radio signals meansV at the sending station for operating the singnal generating and transmitting means in response to ringing current from the cord circuit, means at the receiving station for operating the signal annunciator in response to radiosignals only When the line and cord circuits at said station are disconnected, andmeans at said station for operating the line source of ringing current in response to radio signals only When said circuits are interconnected.

9. In a telephone system, including tvvo central oiiice stations and a. plurality of voice channels connecting said stations7 each of said voice channels including a line circuit and a cord circuit, ladapted to be interconnected, at each station and a transmitting medium, means at eacli station for transmitting radio signals, means at eachstation lforV annunciator, a line 'source of ringing` cur-4,

rent, means responsive to'iinging current from the cord circuit for operating thefsigfl nal transmitting ineansat that station,ineans for operating the signal-annunicator atltli'at station in response to radio signals only when the line and cord circuits at that station are disconnected, and ineansfor operatingtlie line source of ringing current at that station Y y in response to radio signals only When said circuits are interconnected In testimony whereof, We have signed our names to this specification this 18th day of May, '1926. i V

CHARLES S. DEMAREST. OVEN H. LQYNES. c Y t

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