US1569006A - Telephone system - Google Patents

Description

Jan. 12 1926. 1,569,006

G. DEAKIN TELEPHONE SYSTEM Filed Sept. 13, 1924 //7 venfori Gem/d Dew/fin Patented Jan. 12, 1926.

1,569,006. UNITED STATES PATENT OFFICE.

GERALD DEAKIN, OF ANIl/VERI, BELGIUM, ASSIGNOR T WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEEV YORK, N. 'Y., A CORPORATION OF YOR'K.

TELEPHONE SYSTEM.

Application filed September 13, 1924. Serial Ito. 737,478.

To all w/zomit may concern:

Be it known that I, GERALD DEAKIN, a citizen of the United States of America, residing at Antwerp, Belgium, have 111- 5 vented certain new and useful Improvements in. Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to such systems as are provided for dealing with the traffic of private branch exchanges. The system described in the present specification has been designed particularly for dealing with the traffic between subscribers of private branch exchanges and a main exchange.

in accordance with one feature. of the invention, the telephone system comprises an automatic switch adapted to be selectively operated to establish both outgoing calls from and incoming calls to a line.

Preferably such an automatic switch may consist of a line finder which, in addition to selecting a calling line, may be set, under the control of an operator, upon the terminals of a desired line.

The line finder switch is preferably controlled in its operation to extend an incoming call to a desired line by means of an opcrators equipment in which the desired line and the line with which said finder switch is associated are represented each by means of a key, the operation of both keys causing the line finder to establish an incoming connection to the desired line.

In accordance with a further feature of the invention, the operation of the key, associated with the desired line, in the operators equipment causes a signal device to operate, should the desired line be busy upon the operation of the key.

in accordance with a further feature of the invention, the line finder switch comprises a pair of test brushes, one normally connected to control the switch in its hunting operation over a calling line, the other connected by means controlled by the operator to adapt the switch to extend an incoming connection to the desired line.

In accordance with another feature of the invention, a signal device is arranged to be operated when the line finder is set upon the terminals of the called line.

The invention will be more fully under-.

. exchange apparatus and the other connected with his line on the terminals of the linefind'er switches. In either case, the subscriberis prov.1 ded with two bells or an annunclator arranged to distinguish between calls from the local exchange and from the main exchange. The apparatus for establishing local calls may be of any usual well known type and forms no part of the present invention.

The line finder switch 9 is one of a group of line finder switches having access to the calling line. This group of line finders is set in action by a starting circuit apparatus indicated below the horizontal dotted line in the lower left hand corner of the drawing and consists of the starting relays 6 and 8 and the connections leading therefrom. Upon the initiation of a call, a group of line finders is set in operation in the usual manner in search of the calling line. Each line finder is operated by the self-interrupting stepping magnet Hand is controlled in its operation by a test relay 19 which energizcs when the calling line is seized to disconnect the stepping magnet 14.

A link circuit leading to the main exchange'is indicated at 32 and 33. Normally this link is disconnected from the line brushes of the line finder switch by means of the relay 23 and connected through the back contacts of this relay to the attendants apparatus indicated above the horizontal dotted line in the upper, part of the drawing.

When a call has been completed over the link circuit, the relay 23 energizes and completes the through connection from the brushes (4 and b of the line finder over the conductors of the-link circuit to the mam exchange. The attendants apparatus indicated in the upper portion of the drawing idicated in dotted lines.

consists of the usual head-set and dial switch and a number of keys 25, 26, 27 34 and 40, the purpose of which will be'more fully explained in the description of the operation of the system.

At .the left hand side of the drawing and above the starting circuit apparatus, as

hereinbefore mentioned, is indicated an apparatus for giving a signal to the calling subscriber in case all the link circuits leading to the main exchange are busy. This signal apparatus consists of a vibrating relay 35 which interrupts its own circuit to produce a tone in the secondary winding located upon its core and this winding is connected to the ring conductor of the called line through the line relay 3.

This invention is of such a nature that it will be best understood from the following; description of the operation of the system:

Upon the subscriber at substation 1 desiring connection with the main exchange, he throws the switching key 2 so as to connect his substation circuit to the terminals of the line finder switch 9 thereby disconnecting his line from the local private branch exchange apparatus, the leads to which are in- I He then removes his receiver, thereby completing a link circuit for the line relay 3 associated with his line and W1 'ch may be traced from battery, contact of relay 5, through the winding of relay 3, right back contact of relay .1:, ring conductor thence through the outer left contact of switching key 2, through the sub station 1, back through the outer right contact of key 2, left back contact of relay 4 to ground. The line relay 3 energizes in this circuit and closes a circuit for the relay 6 from battery, inner contact of key 7 through the winding of relay 6 to ground at the left armature of relay 3. Relay 6 is made slow-to-release in the usual well known manner and upon energizing closes the circuit of relay 8 and other similar relays in parallel therewith. At its right'hand contact relay 3 connects the low resistance left.

hand winding of cut-off relay 4: to the test terminal of the calling line. v

The relay 8, upon energizing, closes the circuits of the power magnets. such as 14, of those idle line finder switches 9. which have access to the calling line. The magnet 14; operates to step the brushes (1, 7), c, and (Z over the contacts in the bank of the line finder switch 9 until the teri'ninals of the calling line are reached when the circuit of the test relay l9 is'closed as follows: from ground, resistance 20, outer left front contact of relay 8, right contact of relay 21, make-before-break contact of relay 22 through the winding of relay 19, brush 0 and terminal 9 of the line finder, right contact of relay 3, through the left hand windmg of relay 4 to battery. The test'relay 19' energizes in this circuit. The test relay also connects at its front contact its own Winding directly to ground at the inner right armature of relay 22. The cut-off relay 4 energizes in series with the test relay 19 and disconnects the line relay 3 but maintains its own connection to the test terminal g of the calling line through its right hand winding and outer right armature and contact. The direct connection of ground through the winding of test relay 19 maintains the calling line busy to other line tinder switches. I Should a double test occur, that is, should two test relays 19 of a pair of line finder switches energize owing to the simultaneous engagement of the brushes (1 upon the terminal 57 of the calling line, the increase in resistance due to introduction of the right hand winding of the cut-oif relay stupon the energization of this latter relay, will cause one or both of these test relays to deenei'gize owing to the increase in resistance of the test circuit, whereby the line finder switch or switches move their brushes oil the terminals of the calling line.

Upon the energization of the relay 19 when the brushes (6 to (Z make engagement with the terminals 6 to h respectively of a *alling line. the circuit of the power magnet continues through the winding of the relay 23 and right armature of relay 24 to ground. The relay 23 is of suflicient resistance to prevent further operation of the magnet 14 in series therewith. The relay 2", however, energizes in this circuit and disconnects the key 25 from the main exchange end of the link circuit, and in place thereof connects the link circuit through to the calling line. The relay 23 removes ground from the circuit of relay 2 thereby preventing the attendant from listening to the conversation carried on over the link circuit, by throwing the switch 26. As the relay 24: cannot now be energized, no ringing current can be sent over the link circuit by the throwing of key 2?. Relay 23 disconnect-s ground from the lowermost contact on the key 25, thus making it impossible to energize the relay 28, should key 25 be thrown. The relay 23 finally energizes the relay 22. The connection of the link circuit through to the calling line connection upon the operation of the relay 23 causes the low resistance relay 29 connected in the ring conductor to energize and this relay in turn energizes the slow-torelease relay 30. The relay 30 energizes and connects the winding of the relay 23 to battery, through resistance 31, thus maintaining the relay 23 energized until the calling subscriber hangs up his receiver. The relay 30 being slow-to-release does not release its armature when the quick acting relay 29 responds to the dialing of the impulses. The energization of the relay 22 transfers the ground connection of the resistance 20 maintaining the cut-off relay 4 energized to the outer bottom armature of relay 23. The circuit of the cut-oil relay 4 now extends from battery, both windings of the relay in series, terminal 9, brush 0, through the winding of relay 19, contact and outer right armature of relay 22, outer bottom armature of relay 23 to ground.

The calling subscriber is now connected through the contacts of relay 23 to the link circuit 32 and 33 leading to the main ex change. and if this exchange is equipped with automatic apparatus the calling subscriber waits for the usual dialing tone transmitted from the exchange before dialing the number of the desiredsubscriber or if the exchange is equipped with manual apparatus, waits forthe answering of the A operator. It will be noted that the line circuit is free from all shunts. The sole impedance remaining in series with the circuit is that of the relay 29 of low resistance. The connection is secret and may not be disturbed by the attendant even if the keys 2", 26, 27 before referred to, or the key 34, orthe link trans-fer key 7 are operated. During conversation the relays 4, 19, 22, 29, 30 and 23 are energized.

At the end of the conversation the calling subscriber hangs up his receiver and the relay 29* deenergizes causing the release of relays 30 and 23. The relay upon deenergizing opens the circuits of relays 22, 4 and 19, the relay 22 being slow-to-release does not make its back contact before the relay 19 releases.

hen all the link circuits are busy the sip; nal circuit is closed at the contacts of the relays 22 of' the-link circuits through the winding of relay 5. This relay upon energizing disconnects direct battery from the line relays 3 of the calling lines and in place thereof connects these relays to battery through an inductive winding of a vibratory buzzer and the high resistance of relay 36. Now. when a calling subscriber attempts to establish a call during the time all the link circuits are busy the line relay 3 does not operate, owing to the high resistance of relax 36. The relay 36, however, does operate and closes at its front contact the circuit of the operating winding of the buzzer 35, thereby inducing a tone in the secondary winding connecting in series with the line relay 3 of the calling line, and as this relay is connected to the calling line, the tone will be heard in the receiver in the usual manner.

. Upon a call incoming over the link cirouit from the main exchange, ringing current from the main exchange operates the relay 37 which is bridged across the line through the back contacts of the relay 23, the relay 37 energizes and locks up through its right hand Winding, the circuit being traceable? from battery, right hand winding of relay 37, lower normally closed contact of key 25, outer bottom armature of relay 23 to ground. The relay 37 also closes a circuit through the winding of relay 2.1, and lights the link circuit lamp 38. The relay 21. upon energizing opens the circuit of the magnet 14 of the line finder switch 9 and thecircuit of the test relay 19 thereby holding the link circuit busy against selection by a private branch exchange subscriber for an outgoing call.

The attendant upon observing thesignal lamp 38 throws the key 25 which energizes the holding relay 28 from battery, through the winding of relay 28, contacts of key 25 to ground through the outer bottom armature of relay 23. The throwing of the key 25 also closes the circuit of the guard lamp 39 and opens at its lower contacts the look ing circuit through the right hand winding of the link circuit relay 37 so that this relay deenergizes and opens the circuit of the link circuit lamp 38. The key 25 also connects the operators telephone set across the main exchange end of the link circuit.

The relay 28, upon energizing,- connects a shunt across the link conductors 32 and 33 for supervisory purposes, maintaining relay 21 energized by connecting ground to this circuit at the left armature of relay 28 and closes a locking circuit for itself from battery, through the Winding of relay 28, upper contacts of release key 34, innerright armature of relay 28 to ground at the inner left armature of relay 22. The lamp 39 is connected in parallel to the winding of relay 28 in this circuit and accordingly continues to glow throughout the connection until the release key 34 is thrown. The circuit remains in this condition and the attendant communicates with the calling party, requests the number of the desired line and then restores the key 25 to normal position. The relay 28 remains energized over the lOOklIlgCIICUllZ before traced, and the guard lamp 39 continues to glow. The link circuit is held busy by the continued energization of the relay 21.

The attendant now ascertains whether the line of the Wanted party is busy. To effect this the attendant depresses the correct line transfer key 40. Should the line be busy, the relay 41' energizes by the closure of the circuit from battery, through the Winding of relay 41, left contacts of key 40, front contact and left armature of cut-off relay 4 of the desired line, to ground. 3 The relay 41 upon energizing closes the circuit of the pilot lamp 42, thereupon indicating to the attendant that the desired line is busy. The

attendant now throws the key 25 and informs the calling party that the wanted line is busy and if the calling party decides to call again, he hangs-up his receiver and releases the connection at the central office after which the attendant restores the key 25 and releases the link circuit at the private branch exchange by momentarily depressing the release key 34 which opens the locking circuit of the relay 28 which deenergizes and causes the relay 21 to deenergize.

If the wanted line is free, the attendant causes the line finder switch 9 to move its brushes into engagement with the terminals of the line of the wanted party by simultaneously depressing the key 40 of the line of the wanted party and the key 7 of the link circuit over which the call has been extended from the main exchange. This operation causes the power magnet 14 to move the brushes a, b, c and (Z into engagement with the terminals 6, f, g and 7b, respectively, of the wanted line. When the brushes engage the terminals of the wanted line, outoff relay 4 energizes as before explained, closing the circuit of the relay 41 which in turn closes the circuit of the pilot lamp 42, when. the attendant releases the keys 7 and 40. The setting of the line finder upon the terminals of the wanted line is effected in the'following manner: The depression of the keys 40 and 7 causes the. circuit of the power magnet 14 on the line finder 9 to be closed in a circuit from ground, at the inner ri 'ht armature of relay 22, back contact of re ay 19, outer armature of relay 43, through the winding of power magnet 14, left armature and front contact of relay 21, outer left contacts of key 7, back contact and left armature of rela 41 to battery. The test cir cuit of the nder switch is closed from ground, at the right armature of relay 41, right contacts of key 7, inner right armature and back contact of relay 43, through the low resistance right hand winding of relay 43 to brush 0? of the line finder 9. The depression of key 7 opens the circuit of the relay 6 so that the operation of no other finder switch is initiated, thereby preventing the search for and selection of the desired line so long as the key 7 is depressed. When the wanted line is reached, the circuit of the relay 43 is completed as before traced, to the brush d and then through the terminal h, right contacts of key 40, through the left hand winding of relay 4, to battery. The relay 43 energizes and opens at its outer armature the circuit of the stepping magnet 14 of the line finder 9 thus bringing the brushes a, b, 0 and d of this line finder switch to rest upon the terminals of the wanted line as designated by the depression of key 40. Simultaneously, the relay 43closes the circuit of the test relay 19 over its inner right armature and front contact. This relay energizes and locks up in the manner before described directly to ground at the innerright armature of relay 22. f

It will be noticed that the circuit of th 7 power magnet 14, before traced, extends to battery through the back contact and left armature of relay 41, thus if the desired line is busy, the relay 41 will be energized upon the depression of key 40, and Wlll prevent the closure of the circuit of the magnet 14 before traced. Thus, an operator is prevented from extending a communication to a busy line.

When the relay 43 energizes, it opens at its inner armature the circuit of its low resis ance right hand winding, but the relay remains energized over its high resistance left hand winding. This operation prevents the energization of the relay 43 from efiecting the operation of the relay 19. l/Vhen the cut-off relay 4 energizes, the pilot relay 41 is energized from battery, through the winding of relay 41, left contacts of key 40 to ground at the left armature of relay 4. The relay 41 closes the circuit of the pilot lamp so that the pilot lamp 42 glows and the attendant now releases the non-locking keys 7 and 40 and the relay 43 deenergizes.

When the keys 40 and 7 are released, the test relay 19 and the cut-off relay 4 deenergize. A locking circuit is closed for the relays 4 and 19 from ground, at the inner right armature of relay 22, armature and front contact of relay 19 and through the winding of this relay, brush 0 and terminal 9 on the calling line, to both windings of relay 4 in series to battery. The relays 21 and 28 remain energized and the relay 21 opens the locking circuit of the stepping magnet 14 of the line finder switch 9 so that the relay 23 cannot become energized when the test relay 43, connected to the brush d of the line finder switch, is released, should the starting relay 8 be energized owing to some other operator having initiated a call.

The attendant may now ring the wanted party by first throwing the key 26 and then key 27. When the key 26 is closed, relay 24 and relay 50 are energized in this circuit, from battery, through the winding of relay 50, lowermost contact of key 26, through the winding of relay 24 to ground at the outer bottom contact of relay 23. Relay 24 upon energizing connects the ringing key 27 to the link circuits 32 and 33, and ringing current is applied through the. contacts of the ringing key 27 to the link circuit in the usual well known manner.

Upon restoration of the ringing key 27, the attendant remains connected to the called line over the contacts of the key 26. Upon the response of the wanted party the circuit is established by relay 50, from ground at the inner right armature of relay 50, through the left hand winding of retard coil 51, inner top contacts of key 25, outer top contacts of key 26, inner top contacts of key 27, the outer left armature of relay 24, brush a, terminal e, through the local subscribers-substation and backto terminal f,

mam

ate, and this relay closes the circuit of the slow-to-release relay 30. The relay 23, however, does not operate when the slow-torelease relay 30 attracts its armature owing to its circuit being opened at the back con tact, of the relay 24, which is'energized at this time. The link circuit, therefore, re-

mains open, so that the attendant may con verse with thewanted partyunheard by the callingparty at the main exchange, or the attendant may converse with the calling party at the main exchange unheard by the called party by throwing key 25 without re: storing the key 26.. When the desired party informs the operator that he will take the connection the attendantrestores key'26' .to normal position, and this operation releases th relay 2d. The relay 2%, upon deenergizk ing, closes at its back contact the circuit of the relay 23, which now energizes, closesthe link circuit through to the wanted party, and closes the circuit of relay 22 inthe manner before explained. The relay 22, upon energizing, opens the locking circuit of the relay 28 at its inner left armature. The relay ,38 deenergizes and opens the circuit of the relay 21 and of the guard lamp 39. The calling and the called parties are now connected for conversation over the conductors 32 and 33 of the link circuit, and it is impossible for the attendant to disturb or hear th conversation, no matter which key is thrown, the conversation being entirely secret. At the end of the conversation when the called party hangs up the connection is released in exactly the same way as on an outgoing connection as hereinbefore described.

It will be observed that the guard lamp 339 will glow upon the receipt of an incoming call and will continue glowing until the call is answered by the desired party removing his receiver. In this way the tying-up of a link for an unnecessarily long time interval is guarded against. -If the call remains unanswered the operator, in order to release the link, must depress release key 34: which releases the local connection, removes the shunt across the conductors 32 and 33 and places the dial of the operators set in an operative condition for the control of an automatic apparatus if provided.

Should the attendant desire to establish an outgoing link call and then transfer it to a line of the local exchange, she proceeds in the following manner :The keys 25.and 34 of any link circuit are thrown. If the link circuit is idle, the guard lamp 39 associated therewith-light immed t y- -I-t it 'i l y."

i'islamp does 1i tg1ow.-. e'sth w got thek'ey- 2:1 afree lin-kcircuit closesthe circuit. for relay, 28 from ground, oute'r'jbot .tom. arniature relay 2? lowermost off; normalcontact of key 25, through the winding; at: rel y 28.; I 1 batte y e. el y: 2,8

energizes; and} closes the circuit of the; guard lamp 39 and of the relay 21in themanner hereinhe-fore explained. ,Tl1je;.guar d lamp,- 39 lights and the rel y. 2 ope s the circu t of the powerinjagnet l t and of the test ,re lay-19 so that theiline,findelifii zm lntaihqd busyfto all outgoing callsestablishedhy subscribersa thrown. When the attendant has obtained the, desired party, the key 34 is restored,,if it had been tln own,thus causing the relay.

The. throwing, of the key Bhremoves re tardation coil 10 from across theili nk-circuit, conductors 32iand; .335; so that the attendantisset isnow, placed, directly acros s these con? ductors'i topthe main exchange, and if the 1 tte1=...i full auto atic, h t endan qm y; dial from hertelephone'set in the usual way, in order to establish the desiredconnectiom If the ma anges Q 't c m o bat: tery type, the releasing key-34 need I10 e 28 t0 lo k-lip th ough s-inner r g t a -.1 I

tureand shunt to be'placed across the link circuit all as prevlously described for an incoming call. The attendant now transfers the call to any line of the local exchange in exactly the same way as if the call had been an incoming call, as fully hereinbefore explained.

For night service certain subscribers may be connected to links to the main exchange in the usual way by throwing the night service key (not shown) which disconnects the line of a ubstation from the local apparatus and connects this line to the outgoing end of a link to the main exchange.

It will be seen that the line finder switch 9 operates with a hunting motion to extend both outgoing and incoming calls thereby providing an exceedingly eflicient telephone system.

What is claimed is:

1. In a telephone system, subscribers lines, a finder switch in which said lines terminate, a trunk, means responsive to a call on one of said lines for operating said finder to extend such line to said trunk, an individual key for each line, a key for said trunk, and means responsive to the actuation of one of said line keys and said trunk key for causing the operation of the finder to extend said trunk to the corresponding line as a called line.

2. In a telephone system, subscribers lines, a finder switch in which said lines terminate, a trunk terminating in the brushes of said finder switch, means responsive to a call on one of said lines for operating said finder to extend such line to the trunk, an operators position, individual keys at said position one for each of said lines, a key for said trunk at the operators position, and means responsive to the joint actuation by the operator of one of said line keys and said trunk key for causing the operation of the finder switch to extend said trunk to the corresponding line as a called line.

3. In a telephone system, subscribers lines, a finder switch in which said lines terminate, a trunk serving for incoming and outgoing calls, means responsive to a call on one of said lines for operating the finder switch to extend the calling line over said trunk, an operators position, individual keys for each of saidlines and a key for saidtrunk at said position, a signal at the operators position, means responsive to the actuation of one of said line keys and said trunk key for causing the operation of the finder switch to extend said trunk to the corresponding line, and means responsive to the actuation of the individual line key for actuating said signal it the line is busy.

4. In a telephone system, subscribers lines, a finder switch, a trunk leading to said finder switch, means responsive to a call on one of said lines for operating the finder switch to extend such line to said trunk,

individual keys for each of said. lines, a key for's'aid trunk, a signal, means responsive to the operation of .an individual key and said trunkkey for causing the actuation of the finder switch to extend the trunk to a corresponding called line, means for rendering-said keys ineffective to cause the operation of said finder switch if the called line is busy, and means controlled by said keys when the called line is busy for actuating said signal.

5. In a telephone system, lines, a line finder switch in which said lines terminate,-brushes on said switch, a trunk circuit for completing incoming and outgoing calls, means for operating said switch to connect said trunk to one of said lines, an operators position, keys at said position, and two different test circuits each leading through difierent brushes in said finder switch dependent upon whether a subscribers line is calling or being called, one of said test circuits being under the control of the subscriber and the other under the control'of said keys at the operators position.

In witness whereof, I hereunto subscribe my name this 21 day of August A. D., 199A.

GERALD DEAKIN.

subscribers DISCLAIMER 1,569,006.Gemlcl Deaicin, Antwerp, Belgium. TELEPHONE SYs'rEM. Patent dated January 12, 1926. Disclaimer filed July 12, 1930, by the assignee, Western E loot Pic Company, Incorporated.

Hereby enters this disclaimer to the said claims of said Letters Patent which are in the following Words to wit:

1. In a telephone system, subscribers lines, a finder switch in which said lines terminate, a trunk, means responsive to call on one of said lines for operating said finder to extend such line to said trunk, an individual key for each line, a key for said trunk, and means responsive to the actuation of one of said line keys and said trunk key for causing the operation of the finder to extend said trunk to the corresponding line as a called line.

2. In a telephone system, subscribers lines, a finder switch in which said lines terminate, a trunk terminating in the brushes of said finder switch, means responsive to a call on one of said lines for operating said finder to extend such line to the trunk, an operators position, individual keys at said position one for each of said lines, a key for said trunk at the operators position, and means responsive to the joint actuation by the operator of one of said line keys and said trunk key for causing the operation of the finder switch to extend said trunk to the corresponding line as a called line.

5. In a telephone system, subscribers lines, a line finder switch in which said lines terminate, brushes on said switch, a trunk circuit for completing incoming and outgoing calls, means for operating said switch to connect said trunk to one of said lines, an operators position, keys at said position, and two different test circuits each leading through different brushes in said finder switch dependent upon whether a subscribeii"s line is calling or being called, one of said test circuits being under the control of the subscriber and the other under the control of said keys at the operators position.

[Oyfioz'al Gazette J My 29, 1930.]

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