US1629007A - Telephone-exchange system - Google Patents

Description

E. R. SMITH 'TELEPHONE ExcHANGE SYSTEM ,way 17,1927. y 1,629,007

Filed A111411 9, 1925 roms y Affy.

- ent invention, the originating operator goes Patented lllay 17, 1.927.

UNITED STATES PATENT OFFICE.

ERMY R. SMITH, OF MAPLEWOOD, N JERSEY, ASSIGNOR, .'BY'MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application lecl April 9, 1925., Serial No. 21,782.

y This invention relates to telephone systems and more particularly to improvements in trunk circuits therefor used in the establishment of connections between' manual exchanges.

llhe invention is'adapted for use in sys-- tems in which calls `received at one exchange by a so-called A operator areextended by means of a trunk circuit to an operator of a dist-ant exchange commonly called a B operator who thereupon completes the call to the desired subscriber. In such systems,V it is now usual for the A operator upon receiving` a call from a calling subscriber and ascertainingthe number desired, to employ a call wire leading to the desired exchange to communicate with the B operator. The B operator in responding, and after ascertaining the number desired. and the exchange at which the A operator is located, will assign a trunk to the A operator. The A operator then connects the calling subscriber tosaid trunk, and the B operator extends the trunk to the called subscribed. rEhis is known as the callwire system. Y

The present invention is designed to provide a ymeans. for connecting switching trunks to an operatorstelephone set, such as that of a B operator, so that traliic can be handled by the so-called straight-forward method of operation7V wherein no call-wire is employed and the circuit from calling` subscriber to called subscriber is progressively established without the necessity of one operator asking another which trunk she shall use. According to the presstraight forward and chooses a trunk herself so that when the call is placed in the hands of the terminating or"B operator the connection has already been established that far.

It is an object of the invention to provide a means whereby upon the selection of an idie trunk leading to a distant exchange b v an A operator. the B operator may manually connect such trunk to her set and at the sa if time automatically notify the A operator that she, the B7 operator, is ready to receive the designation of the called line. After receiving the number of the desired subscriber from the A operator, the B operator Will thereupon complete the call in the usual manner.

A feature ofthe invention comprises a means whereby 'a momentary tone is transmitted over the switching-trunk to the A operator when the B'operator connects such trunk to her set.

Another vfeature of the circuit arrangement is the provision of means to enable the B operator to completea connection to the subscribers line byreinoving a plug from a lirst jack to which a call hadbeen extended and inserting it into a second jack.

A further feature resides in an arrangementV for employing this invention in systems using the call circular method of operation so that a position using this straightforward method of trunking can also handle tratlic of adjacent positions arranged for call circuit operation. Vhen the operators set of a position employing the present invention is arranged for connection to a -oall circuit position, provision is made for transmitting a signal to an operator at 'the' outward end of the call circuit in case Another feature of the present inventionVV is the provision of a plurailty of jacks lead- .ing tothe operators headset and the provision of means associated therewith to render effective one of said jacks at a time. By means of this feature the operator may insert a second incoming trunk into one of' these jacks while she is still communicating withan operator over a first trunk Aso that when she removes the plug of the first to complete a connection to a called line the second Will immediately become effective. By the provision of this meansV the service may be quiclened and delays due to the mechanical handling olf the apparatus reduced to a minimum.

One embodiment of the invention is illustrated in the acroinpairying drawing Which illustrates one form of the invention. In Fig. l, A shows a trunlf; leading from an outgoing exchange `which desires a connes. tion with an operator at the local exchange.

Only the portion of the 'l'riinl termin: yingat the local exchange is shown. l", illustrates a listening circuitto nhich the trunk circuit may be connected. l-Tig. 2 represents a subscribers line jack. )nly those portions' of the circuit arrangement necessary to a proper understanding of the invention are shown.

A detailed description of the invention Will now be given. Assuming that an A operator at an outgoing exchange desires to be connected to a subscriber at the exchange `wherein circuit B is located; she will therefore connect to the calling subscriber in the usual manner and extend the connection by seizing a trunk leading to the desired e2;- change, in this instance, the exchange at Which circuit B is situated. Assuming that the jack into which the A operator plugs is that associated with trunk A, a signa Will be forwarded at the incoming exchang to light lamp l. The operation of lamp l effected as follows: grounded battery of relay 2, left-hand winding of relay 2, normal make-before-break contact of relay 3, lower right-hand Winding of repeating coil Ll, through the loop at the calling, A operators end, back through the upper righthand Winding of repeating coil 1land the outer normal contacts of relay 8' to ground througl'i the right-hand winding of relay Relay 2 Will thereupon pull up its armature and cause the actuation of lamp l. in a circuit from grounded battery, filament of lamp l, normal right-hand contacts of relay 5, left-hand Winding of relay 3 to ground through the armature and alternate contacts of relay 2. The operator at this exchange Will thus be apprise-:l that vthere is a call over trunk A associated With lamp l that awaits connection to a subscriber at this eX- change.

Relay 3 due to the energization of its lefthand Winding, Will attract its armature to break the normally closed contacts thereat and supply a ground for relay 2. vrEhe lefthand Winding of relay 2 will now oe-maintained energized by this ground. it is seen therefore thatthe actuation of rel ay 8 causes the circuit leading to the A operator to be broken.

rlhe operator at this end Will immediately take plug 6 of trunk A associated with lamp l and insert it into a listening jack such as 7 or 8. .frssuming'that she plugs into jack S, a circuit will be closed from grounded battery through supervisory relay 9 of the trunk, lower left-hand Winding of repeating coil f-l through the ring ofthe `plug and jack, inner ieft-hand normal contacts of relay l() in the listening circuit, lower lefthand Winding of repeating coil ll, through the Winding of relay l@ lo ground. Supervisory relay 9 operates in this circuit and closes a circuit for the operation of relay as follows: Grounded battery, right-hand winding of relay 3 operated contacts and armature of relay 9, left-hand winding of relay 3 to ground through the operated contacts and armature of relay 2. Relay 3 therefore is controlled to maintain its armatures in a position that keeps open the circuit leading to the A7 operator.. The reasons therefor ivill be hereinafter set forth. Relay l2 operates and provides a ground for sleeve relay 5 in the trunk, which operates and causes the extinguishment of lamp l. The circuit therefore extends from grounded battery, Winding of relayA 5, sleeve of the plug and jack respectively, Winding of relay 13, normally closed armature and conta cts of relay l0 to ground through the righthand armature and contacts of relay l2 to ground. Relay l2, by pulling up its lefthand armature ivill also close a circuit for relay la, through the normal make-beforebrealr contacts of relay l5.

it is of note therefore that sleeve relay 5 in the trunk circuit does not operate until after supervisory relay 9 has operated. This is for the purpose of keeping relay 3 energized and preventingl the switching trunk from functioning to transmit a false signal to the A operator, upon the insertion of plugl G into jack S. if this feature were not provided, and the signaling circuit to the A operator not broken, the lamp 35 or other means, at the A ope'ratoi"s position ivould be caused to operate upon the insertion of plug 6 into jack 8. rhis false signal would erroneously be construed by the A operator to indicate that the B operator had connected to the called subscriber; and hence the A operator would ring over the line. However, With this means. as above outlined, no such false signal is flashed and hence the A operator Will not ring. rThis prevents a so-called false plugged-up signal to the A operator. Of course, after the B oprator removes the trunk plug fron: jack S, and inserts it into the called subscriber-s jack 18, as Will hereinafter be disclosed, the A operator will then be signaled in the usual manner and will apply ringing current to the line.

It has been seen tha relay i3 operated in the circuit for relay 5. Tais is for the purpose of disconnecting the tip, ring and sleeve conductors from jack T in order to prevent lll Cil

false operation in case the operator plugs anot-her switching trunk into this jack before plug 6 is withdrawn from jack 8. i Relay 14 operated after the operation of relay 12 and by pulling up its inner lefthand armature connects a tone to the line from source 16. Also it supplies ground for the operation of relay 15 through its righthand armature. Relay 15 in operating. will lock up to ground through the left-hand armature and contacts of relay 12 and will remain operated und-er the control of said re.- lay 12. Relay 15 in locking to this relay will obviously cause a deenergization of relay 14. By making relay 14 slow to release and relay 15 slow to operate the duration of the tone transmitted back to the A operator may be accurately timed.

Upon the release of relay 14, relay 17 will operate in a circuit as follows: Grounded battery, winding of relay 17, outer restored lett-hand contacts of relay ,14, armature and right-hand contacts of relay 15 to ground.

Relay 14 in releasing will cut oii the toner from the line and relay 17 which operates immediately thereafter will through the outer armatures thereof now connect the operators telephone set to the line. The operaers jack 18 toxcomplete the connection.

Upon the withdrawal o plug 6 from jack 8, the supervisory relay will lose its holding lground and release. Supervisory yrelay 9 will also release. Thiswill cause relay 3 to release and obviously closevv the circuitfor the operation of the signal 35 at the A operatorsposition. As the plug 6 is inserted into jack 18 a circuit including sleeve relay and cut-oit relay 19 is closed and both these relays operate. As the loop of the called subscriber-s line is open at this time, the relay 9 does not operate and hence lamp 1 remains dark and relay 3 does not operate as before. The A operator will then know that the trunk is plugged-up to the called subscriber and will thereupon ring over the line.

Relay 14 is purposely made slow in releasing and relay is made slow in operating, in order that the release of rthese relays will malte the circuit- Afunction to transmit the momentary tone. described', over theswitching trunk to the A operator. This tone indicates to the A operator that the switching trunk operator is being connected to the trunk andready to receive the call. As has been seen, after she receives details of the call, she withdraws Aplug 6 from the jack, releasing circuit will'b'e connected to tone 16.

all the relays in the switching trunk; makes the usual busy test and completes the call.

When the called subscriber answers, supervisory relay 9 operates, whereupon relay 3 becomes operated. This operation cuts off battery and ground from the distant Al operator and causes the extinguishment or'. lamp as a signal that the subscriber has answered. Relay 3 also locks in relay 2 and hence the lamp 1 remains dark until the called subscriber hangs up. Vhen this happens relay 9 returns to normal and releases relay 3, whereupon relay 2 is again connected to the distant A operator and lamp 35 is lighted as a signalthat the conversation has ended. The A operator then opens the loop at her end of the trunk and relay 2 releases, whereupon lamp 1 becomes lighted in a circuit including the back contact of relay 2 and the front contact of relay 5. This is va signal to the B operator to remove plug 6 trated in the drawing, the leads of the-call circuitsvshown are normally connected to an operators telephone set, through the -contacts of relay'17. lIt is evident therefore that if the operatoris busy answering a call with the listening jack circuit, relay 17 .will be operated and the operators set disconnected from the call circuit leads. Instead, the clall T iis tone notities the operator at the outward end of the called circuit that the inwardoperator'is'not'y yet free-to answer the call. VObviously, after relay 17 restores, the call circuit leads will` again be 'connected toI the opera tors set and disconnected from the tone.

The call circuit operator will theny passv the call inthe usual manner. It is evident that any number of call circuits and any number of listening jack circuits may bemultipled together, but for purposes of this invention, only one set of call circuit leads and two listening acks are shown.

If jack 7 were used instead of jack 8, in the operation set. forth, relay 10 would function in a similar manner does relay 13 and in place thereof. Thus, if jack 7v were seized and a second switching trunk associated therewith, before a irst trunk in jack S was removed, relay 13 would prevent the connection of the tip, ring', andsleeve conductors to jack 7, and hence assure the seizure of the listening circuit by only .one trunk at a time. Upon the removal of' the first trunk from jack Y8, the second trunk, in jack 7, would, as has been described, be connected to the listening circuit, and relay l()y operate to prevent false operation upon the possible seizure ot the other jack, and so on.

lt should turther he noted that relays 1'() and 13 are slow to release, so that il there a plug irrboth jacks 7 and and the one in jack 8 is ellective, 'relay lf3 willihe operated 'and when the plug in jack tu is removed, relay 13 being" slow to release its armatures will give rel-ay 12 time to become:deenergized. Thereupon relay l5 will return to normal, so that upon the/complete release ol relay l?) and the sul-)sequent cnercization olf relay '12, the tone current from source 1G will he momentarily applied tothe 'truuk now connectedthrough jack 7.

It is seen, theretore,that only one oli the jacks is etlfective at a time. even though a second ack is seized while a lirst is stillihusy. l" he operator may, as a result, handle the apparatus toits ful-l capacity, luy answering' and completing calls practically contemporaneously due `to a lplurality ot jacks 'being available to her, without- Ytear olr causing," confused or false operation.

Vfhat claimedis: Y

l. ln a telephone system, a trunk circuit, an independent circuit having;` listening means associa-ted therewith and adapted to he connected to said' trunk, a source ottone current, land means responsive to the conneet-ionl ol said trunk circuit yto said'y independent circuit to automatically and'sequentially connect said source ot tonecurrent to said trunk, to disconnectI said source of vtone current from said trunk and to connect said listening apparatus to said truuk.

2. In a telephone system, a first trunk ot a certain character, a second^trunk ot' a dii-ferent character', an operators'headset normally connected to said first trunk, means for 'connecting said headset to said 'second' trunk, a source ot tone current, and means tor connecting said source of 4tone current to said iirst ltrunkupon the disconnection therefrom` of sa-id headset and the connection ot' said headset to the other trunk.

ln a telephone system, a trunk ot a certain character, an operators telephone set normally connected to said trunk,trunks ot other character, means for connecting said headset to said other trunks, a source of tone current, and means for connectingY said source of tone current to said trunk of a certain character, upon the disconnect-ion ot' said telephone set therefrom. v

4. In a. telephone system, a plurality of trunk circuits, an independent-circuit having listening means associated therewith and adapted to be cminectedto any ot said trunks, means for associatingv more than one of said trunks with said independent circuit at one time, means for rendering` etfective only one such connection at a time, means for automatically'rendering effective another such connection upon the breaking of a previously effective connection, a source of tone current, and means responsive to the eil'ectivc connection of one ot said trunk circuits with said independent circuit' lor automatically and sequentially connecting said source ot tone current to said trunk, disconnectingj said source et tone current from said trunk and lconnecting` said listening, apparat-us to said trunk.

ln a telephone system, a plurality oil" lrun c circuits terniinating in plugs, a plurality ot jacks, a telephone headset associated with said jacks, means for successively associatingsaid trunks with said jacks, means responsive thereto for successively associatingsaid telephone set to said trunks, said set being automatically connect-- ed to only one of said trunks at one time in the order o' their connection to said jacks, a source of tone current, and means responsive to said' second mentioned means tor momentarily connecting,` said source ot tone current lto said trunks.

(i. ln al telephone system, a call wire circuit. a trunk circuit, an independent circuit having listening vapparat-us associated therewith, means operative responsive to the interconnection of' said trunk circuit with said independent circuit to connect the listening apparatus thereto, a source of tone current, and 'means responsive to said interconnect-ion tor connecting` said source ot tone current to the said call Wire circuit. v

` T. In a telephone system, a. irst trunk, a second trunk, an independent circuit adapted to he connected to said trunks and havingi listening apparatus associated therewith, a characteristic signaling' means, means responsive to the connection of said circuitwith one Ot said trunks'to momentarily associate said signaling means therewith, means operative responsive thereto 'lor connecting said listening apparatus to saidV trunk and transferringthe connection ot said signaling means to the other of said trunks. A

8. In a telephone system, a plurality of telephone exchanges, an exchange X, trunk lines of a certain character leading from some ot' said telephone exchanges to e3:- changes X, trunk lines ot a dilterent character leading` from other ot' said exchanges to exchange X, listening apparatus at said exchange X, said listening apparatus being normally connected to trunks of a certain character and means responsive t-o the connection of said telephone equipment to trunks -ot another character for disconnecting,` said listening apparatus from the trunks normally connected thereto.

'9. In-'a telephone system, a trunk terminating in a plug, listening apparatus associated with a jack, a subscribers line terminating in another jack, a signal, means responsive to the connection of said trunk with ter relay in said independent circuit, a vsecthe first ot said jacks for connecting said listening` apparatus to said trunk and maintaining said signal in a certain condition, and means responsive to the connection of said trunlr With the ot-her of said acks for changing the condition of said signal.

10. In a telephone system, a trunk lin terminating in a plug, listening apparatus associated with a jack, a subscribers line terminating in another jack, aA signal, means responsive to the connection ot said trunk with t-he first of said aclrs for connecting said listening apparatus to said trunk, and means responsive to the connection of said trunk with the other of said jacks for disconnecting said listening apparatus from said trunk and for actuating said signal.

11. In a telephone system, a trunk circuit terminating in aY plug, a relay in said trunkv circuit for controlling a signal therein, another circuit terminating in a jack, a master relay in said other circuit, a subscribers line terminating in a jack, a means responsive to the connection of said trunk with said other circuit, under the control of said 1nasterre lay, for operating said relay in the trunk circuit and maintaining the signal therein in a desired condition, and means responsive to the disconnection of said trunk from said other circuit and its connection to said subscribers line for causing the restoration of said relays and a change in the condition of said sional.

12. n a telephone trunking system, a trunk terminating in a plug, tele-phone listening apparatus associated With an independent circuit terminating in a jack, a masond relay under the control of said master relay and a third relay, means operative responsive to the interconnection of said trunk and independent circuit for causing said master relay to operate and effect the actuation of said second relay, means responsive to the actuation of said second relay to cause the operation of said third relay and the release of said second relay, a fourth relay, and means under the control of said second and third relays for causing a momentary tone to be connected to said trunk and for causing the immediate connection of said listening apparatus to the interconnected circuits under control of said fourth relay, said tone being disconnected from the trunk upon the connection of the listening apparatus thereto. 13. In a telephone system, a plurality of trunk circuits terminating in plugs, an independent circuit having a plurality of acks associated therewith, listening apparatus associated with said independent circuit, means responsive to the interconnection of a plurality of trunks with said circuit by the respective connection of the plugs thereof with said jacks for connecting said listening apparat-us With one of said trunks, and for connecting said listening apparatus to a second of said trunks upon the removal of the plug of the first trunk from a jack of said circuit, a source of tone current, and'means responsive to said first mentioned means for momentarily connecting` said source of tone current to said trunks. l

` In Witness whereof, I hereunto subscribe my name this 8 day of April A. D., 1925.

ERMY R. SMITH.

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