US1580398A - Service observation arrangement for telephone systems - Google Patents

Description

Amd-13,1926. y 1,580,398 Y w A. BENSON SERVICE OBSERVATION ARRANGEMENT FOR TELEPHONE SYSTEMS I1-mam :1P-

lnllham H Eansun Y w. A. BENSON l 'SERVICE OBSERVATION ARRANGEMENT FOR TELEPHONE SYSTEMS April 13,1926. l 1,580,398 Y Filed t. 18, 1921 2 Sheets-Sheet 2 l l l m l l Il Il )I L &

lnllham E Bsnsnn of the ringing current passes through the bridged relays 3l and 33, but only relay 31, which is tuned to respond to this particular frequency of ringing current responds. Relay 3l, upon energizing, closes a circuit for' relay 32 at armature 48. Relay 32, upon energizing, locks itself up at armature 50 to conductor 87, which is grounded through the resting contact of armature 57 and said armature closes a circuit for relay 37 at armature 47 and closes a circuit for the lamp L at armature 49. The operator is apprised by the lighting of the lamp L of the fact that the subscriber at substation A is being signalled. Relay 37, upon energizing, prepares a locking circuit for itself at armature 97; closes a circuit for cut off relay 30 at armature 96; and at armature 95 places a shunt around armature 55 and its resting contact for a purpose to be explained more fully hereinafter.

' energizing', removes the tuned relays 3l and 33 from in bridge of the line at armatures 44 and 46 'so that they will not interfere with the ringing of the bell at the called substation. lt will be noted that the ringing curi rentl passes through the relays and 39 at this time. Relay 39 does not respond owing` to its marginal adjustment and to the small number of turns in its lower winding. rlhe armature of relay 35 is not appreciably affected by the current which passes through the said relay owing to the fact that the noninductive resistance 58 is shunted around the relay at this time.

`When the subscriber at substation A responds to the ringing of his bell by removing his receiver, a direct current bridge is closed across'the conductors 2 and 3, whereupon the source of ringing current is removed by the .f lconnector switch and a source of talking current is connected up instead.

The low i wound series relay 35 at the observing operators position which did not respond to the ringing current Von account of the non inductive shunt around it now responds to the direct talking current by operating its armas ture 54, thereby closing a circuit for release relay 36. Relay 39 however, being marginally adjusted does not respond at this time owing to the fact that its armature cannot i be attracted until current flows through both ground upon conductor 86. Relay 32, upon deenergizing, opens another point in its circuit at armature 50; opens the circuit of the lamp L at armature 49; and at armature 47 opens the initial energizing circuit of relay Cut off relay 30, upon- 37 and closes the followinglocking circuit for the said relay 37: from ground by way of conductor 86, working contact of armature 97 of relay 37 and said armature, normally closed contacts controlled by armature 47, normally closed contacts cont-rolled by armature 73, and relay 37 to-'battery. Vhen ground is placed upon conductor 86 a circuit is closed for the upper winding of electro polarized relay 39. vRelay 39, how-- ever, is not energized at this time owing` to the fact that the current flowing in either winding opposes that flowing in the other. A branch of this circuit extends also by way of armature 62 and its resting contact to the lamp L2 which becomes lighted to notify the observing operator that the called subscriber has answered. Another branch of this circuit extends from conductor 86 by way of armature 59 of relay 38 and its resting` contact and armature 69 and its resting contact to battery, by way of magnet 90 of the recorder R. Magnet 90, upon energizing, attracts its armature 91, thereby forcing the pencil 93 intoV engagement with the moving tape 92. This tape it may be said is suitably marked and dated so that a record as to what time and upon what day a call was made or received can be had. A mark is made on the tape the length of which depends upon vthe length of time during which the magnet 90 is energized. i

The called subscriber, of course, may begin to converse with the calling subscriber as soon as he removes his receiver and is not aware of any of the events which are taking place at the recording operators position. As much as is shown of the talking circuitv is outlined by heavy conductors and it will be observed that it includes the lower winding of relay 39. The lower winding of relay 39, however, has comparatively little inipedence and consequently does not appreciably interfere with the transmission of voice currents.

l/Vhen the conversation is completed the calling and called subscribers replace their receivers. When the receiver is replaced at the substation A the circuit of relay 35 is opened and the said relay, upon d-eenergizing, opens the circuit of relay 36 whereupon relay 38 energizes in series with relay 36 and opens the circuit of the magnet 90 of the register R at armature 59. Magnet 90, upon deenergizing, removes the pencil 93 from engagement with the tape 92 thus terminating the mark being made on the latter. As

a further result of the energization of relay 38 it places the operating magnet 75 of the switch D in multiple with release relay 36 at armature 58, the circuit including arma.- ture 64 and its resting contact. Owing to the high resistance of relay 38, operating magnet 75 does not energize and release relay 36 deen'ergizes. Upon deenergizing, re-

lease relay L 36 .op'ensithe circuitof relayv 38 Aat .armature 56 and removes ground from conductor 86 vat ,armaturev 57. Relays 37 The opera-tor uponv noting-that the lamp L2has becomefextinguished knows that the conversation has terminated and vthat the called subscriber lhas replaced his receiver. She'may Amake vouta ticket if' desired or in any suitable way'record the information thatv' 1 resting contact for the magnet y90 of the l she has gathered. Y y

In regard to the -line Vswitch C it maybe said that switching relay 1l deenergizesupon the -release of the connector switch which was :used to` completer the connection, yand upon so doing restore-s the conditions in the lineV switch Cto normal'.` 1 f ltwill be assumed now thatv thesubscriber at substation A desires to Ycall so-me other subscriber. VWhen the vreceii'fer is removed at substation A, a Vcircuit 'is closed .over the lin-e conductors 2 and3, conductors 2V and 1 tors 4 and 5,- forline relay l2 of the line switch'C. Linel relay l2,^upon energizing,

places ground .upon private normal. con-. duct-or 6 at armature,v 18, thereby closinga' circuit for switching'relay l1 and stepping n an idle trunk line leadingto a iirst selector and when one is found the switching relay 11 Y energizes, not rhaving energized lbefore.

on accountof being short circuited bythe ground potential `which is-kencountered test wiperQl in passing 4over busy testv contacts. Switching. relay 1l, upon energizing,

disconnects the line conductors 4 and 5 from i the winding of line relayl v12 and ground re-v spectively andext'en'ds them by way of armaturesv13 and l5 and wipers20 and tothe line relay fof `the irstselector to whichv the t-runk line upon which the, wipers ai'e erm tending atv this time. The line "and release relays of the said selector now energize in v the well vkno-wn manner andthe latter places ground upon the associated .release trunk conductor, thereby 'closing a 4holding circuit for the switching relayll in the usual inanner. i l Y 1 Inl 'the equipment torsposition, 4'relay'39does not energize for vreasons hereinbeiore given but relay 35,1up-

' on energizing, closes acircuitffor relay '36 at armature 54. Relayv 36, upon energizing, re-

moves? the resistance l58 fromin shunt ofV relay 35 atarmature 55; prepares a circuit forfrelay 38 -at` armature Y56;-.disconnectsY groundfromconductor 87 and places ground upon conductor 86 at armature 57. ,Ingre- The line switch C now operates'in tliewell known manner to select n atthe recording opera' spense to tlieplacing of ground uponfcon` yductor 86y the lamp L2` becomes lighted to apprise'the operator of the fact that a subscriber has his receiver oli' the hook." A cirregister R, withthe` result that armature 91 is attractedand the pencil 93 begins to make a mark upon the moving tape. 92. As' a' further resultl ot' placing ground lupon con-` ductor 86a circuitisclosed orcut yoft' relayY 30 including the resting., contact of armature 96 and said arinature.fCut oii' relay 30, upon energizing, disconnects the" tuned relays- 3l and 33 at armatures 44 and 46. Y,

The vcalling subscriber ,mayl now operate his calling device in accordance jwith the irst digitotthe desired number, thereby bo y producing a correspondingnumberof interruptions in thecircuit of the line relay vof `the first selector to which the connection has been extended. v lIn responseto these interruptions the saidliiie relay causes the selector to raise its wipers to thedesire'd level andy rrotate them in search of an idle rtrunk line leading to a connector switch, assuming vof course, that this` is a 1000 linesystem. In the equipment at the observing operatc'rs ido position, relay 35 falls back each time an ,-5

interruption isg'produced in its circuit and,

upon fallingV back in responsev to the first interruption, removesv a short'circuit' from around relay 38.' Relay 38, upon energiz-VVV ing, i`n series withvrelease relay 36, removes ground from the upper set of wipers of the switches D-D2, inclusive,` at armature 60;

v'opens the circuit or'thcinagnet 90 of the register R at armature 59; and at armature V'58 places the operating magnet 7 5 of the switch D in multiple with release relay 36. Operating magnet .7 5, however, does not en# ergize at this timek on account of the high resistance ofrelay 38. Relay 35, upon energizing, following the interruption produced A Vin, its circuit, short circuits relay. 38 yand closes a circuit for'lrelayv36 vand operating magnet v7 5 .in multiple at armature 54.

Magnet 7 5, uponl energizing, advances theA wipersof the switch D into engagement with the first set of lbank vcontacts.`v Relay 38, being shortcircuited, does'not fallback im'- mediately andl consequently retainsits armatures attracted throughout the series of interruptions. Then relay 35 deene'rgizes in response to the second interruptions produced in'its circuit magnetz'' deenergizes not being able to; retainV its arniature'attracted-V in series with the high resist-ance re"- lio lay 33. (,lperating magnet 75 is energized again each time relay cnergizes and by its subsequent operation advances the wipers of the switch D into engagement with the set of bank contacts corresponding to the digit called. At the end of the series of interruptions relay cornes to rest in an energized condition, whereupon relay 33 deenergizes and opens the circuit of operating magnet 75 at armature 53; closes the circuit of the magnet 90 of the register R at arn'iature 59 thus starting another mark on the tape 92; and at armature 60 places ground upon the upper set of wipers of the switch DD2, inclusive, thereby closing the following circuit for relay 420: From ground by way of armature 57 and its working contact, armature 60 and its resting contact, upper wiper of the switch D, the bank contact upon which the said wiper is resting, normally closed contacts controlled by armature G3, and relay -lfO to battery. Relay 40, upon energizing, closes a locking circuit for itselt and disconnects itself from the wiper of switch D at armature 33, and at armature 3l shifts the operating circuit from magnet 75 of the switch D to the magnet 76 'bf the switch D.

ln response to the calling of the second digit in the desired number the c'nnector switch to which the connection has been eX- tended raises its wipers step by step until they stand opposite the level of contacts in which the desired line terminates.

ln the equipment at the observing operators position the pencil 93 of the rea R is raised from the tape 32 during the calling of this digit in the saine manner be* fore and the operating magnet 76 ot the switch D operates in the same mannsr as the magnet of the switch D operated during the calling of the previous digit and steps the associated wipers around to the set of bank contacts corresponding` to the digit called. At the end of this digit relay 33 falls back as before with the result that the pencil of the register R is brought into engagement with the associated tape again; the circuit of operating magnet 76 is opened; and ground is placed upon the upper set of wipers of the switches D, D and D2. rlhis ground potential entends by way of the upper wiper of the switch D, the bank contact with which it is in engagement, normally closed contacts controlled by armature and relay ll to battery. Relay si, upon energizing, locks itself to conductor 36 and disconnects itself from the wiper of the switch D at armature 65, and at armature 66 tansfers the operating circuit to the operating magnet ZT of the switch D2.

Y ln response to the calling of the next and last digit in the desired number the connector switch to which the connection has been extended rotates its wipers step by step until they come to rest` upon the bank contacts in which the desired'line terminates. The connector switch now Asends out ringing current intermittently to ring the bridged bell at the called substation.

At the observing operators position the results produced by the calling of the'linal digit are similar to the results produced by calling the previous digit and consequently the operating magnet 77 responds by rotating the wipers of the switch D2 into engagement with the set of bank contacts corresponding to the digit called. At, the end of this series of interruptions relay 38, upon falling back7 in addition to the other operations performed, places ground upon the wipers of .theA switches DD2, inclusive, thereby closing a circuit for relay l2 including the upper wiper of the switch D2 and the normally closed contacts controlled by armature 63. Relay 42, upon energizing, locks itself to conductor 86 and disconnects itself from the wiper of the switch D2 at armature 68; shifts the operating circuit from magnet 7T of the switch DL to battery through the resist-ance 93 at armature 70;

opens the circuit of magnet 90 of the registe at armature 69; and at armature 67 disconnects the lamp L3 from the working contact of armature 62 and connects up the lamp lll instead.

lsllien the called subscriber answers, V the connector switch in a well known manner reverses the current flow in the incoming trunk conductors and consequently'in the conductors leading back through the equip,"

ment at the observing operators position to the calling substation. When this occurs he two windings of electropolarized relay 39 which heretofore have opposed each other now assist each other in operating the said relay. Relay 39, upon energizing, replaces the resistance 58 in multiple'with relay 35 at armature G1. rlhis is done so as to afford a better path for the voice currents. As a further result of the energization of relay 39 it disconnects the lamp L2 and connects up the lamp L4 at armature 62 whereupon the lamp L2 becomes extinguished and the lamp L4 becomes lighted to inform the operator that the called subscriber has answered. rfhe calling and called subscribers may now converse with each other as desired, much of the talking circuits asv are shown being outlined by the heavy conductors.

The oberving operator not only knows that the calling subscriber has called a number and that his call has been answered but also knows what number-helias called. This is made possible by the bank of lamps which is suitably arranged before her so as to display the called number. This bank of lamps is connected one to each contact over which the lower wipers of the switches D-D2, inclusive, pass, and consequently one lamp v normal position.

from each switch is; lighted, as soon `as the;v

switch is operated, to show the positionr of.

the Wipersk of that switch, which in turn: is

indicative of the number called. Ofthese; lamps-only one for each switchy is shown, the others, Which arey connected in theY samel manf ner as the one shown, bein-g omitted for the salieof simplicity. i

lNhen the conversation is iinisliedi'theacalling and called subscribers replace their re,-

ceirers. 7Whenthe` receiver is-replace'd' at the substation A, the circu-itefof thelineref( layer' the connector through which the-conf' neet-ien has been extended is op e1ied-,\vhereupon the` automatic switches are'v restored toi lnormal in the usualV manner.` At the observe ing operators Aposition relay 35 deenergizes in response te the replacing of the receiver at the calling substation and opens the cir-.

cuit ci release relay 36 whereupon relayl 38. energizes inl series vvith the saidrel'ayfr and places resistance 93 in' multiple with release relay 36 at armature` 58. Resistance 93. is lower than theiesistancefoflrelay 36 and'.y most of the current which comesthroughy the high Wound relay 38l flows through the saidresista-nce 93.v As aresult release relay 36 ydeenergizcs and -upon so doingy opensthe circuit of relay 38 at armature 56, Whereuponrelay 3S deenergizes also. vAs afurther result of the deenergization of release relay' 36 it removes ground from conductor 86 whereupon relays 40e-42, inclusive,v deener'- gize and the. lamp L4 becomes extinguished.. As a further result ofthev removal ot ground from conductor 86,. cut-"oil relay 30 deenerA gizes and connects up thetunedfrelaysyl..

and 33 at larmatures 44 andati@` Asi aV still further resultv of the deenergizationof; 're,

lease rela-y- 3.6,*it places ground; upon1 conductor 87 at armature57 thereby closing a circuit for releasefinagnets-78, 79, vand 80 in,Vv multiple 'through the, olii-normal contacts 8l., 82, and 83?. By the operationigof these r e,- lease inagnctsftheWipers ofthe switches` D, D-, and D2 `are restored to normal `po sition, the circuit of each of the release mag nets being broken at its associated olf-normall contacts when the associated Wipers rea-ch.I

now restored to normal position and' isr'eadyV for another call-either incoming or outgoing..A

`From an examination of the drawings it 'may be seen that when a. subscriber at substation A is'cal'led the operation ofthe equipment at the observing operators po sition is the same as When thesubscrjiber at substation A. is called With the exception that the tuned ,relay 33 responds in this case and closes ay circuitV 'for rthe associated relay 34:. Relay 34,'upon energizing closes a locking circuit for itself, closes al circuit for relay S7, and closes acircuit'for the lamp L. .Since the subscriber at' sub- The entire, apparatus is l is disclosed in station A has made no complaint regarding his service the operator need not payanyat-i tentionj tothe-lighting of the laInpLf.` 5

It sometimes happens ,that the conductorsioi? avg trunk, line become accidentally reversed.; This may not caues anytrouble vtofariseiii some l'cases but' when lthe con` Y nectron is.extendedthroughV an automatic.

repeater ,the reversal yof' currentwhich` oc; curs when .a trunk: lineV ist selected in vvhijch f the=conductors are, reversed causesI the; op? eration of certain Telaysinl the repeater which render .thef impulse repeating. circuit;

Vinoperative-.randi consequently prevents the connection vfreni* beingextended any further. lit the subscriber Whose line is under oblservation,is making a calli andrjone, o the l selecting;KV switches in*l the exchange cue-ts through upon ka reversed trunk the.--vel'peetio-v .polarized -relay ,39l atthe4 l,reclordin-g op.,-

erators lposition immediate]y energizes and extinguishes the kruip-L2. Since allof the-f digits of: the desired nu-nfiberv have not yet .beencalled relay i2 Willi.not be energizedV and thelanip Ljis lighted instead of tlief. 1

lampvL* which lights upon.V the respons'elfof .The opera-tor, upon the called subscriber. noting the lighted condition ot thev lam-p L3,- throvvs the key K, which is a combined Pelea-Se; and holding. key, into holdingposition, therebybridging the,l impedance coilf to holdup the connection in casethecalling subscriberrcpl-aces-, his receiver.v I `The op-l erator now observes the indicating .la-inps and determines Whatroutetlie call ha-s ,taire-n;

`45 across the conductors 2 and. 3( iso asv ico and 'hovv many digits havebeen. called... Thisinformationshe gives-to anl attendant H Who makeshaste to itin-dythe/reversed triml Assoon ias, the attendant*hasv disccfiveredv which- 'trunk isI in trou-blehe (mayl release` the switch*through vvhiehv the cormectioigiv lis extended to it and make thee trunkbusy until helaas time to-*.clear upV the trouble. As soon as the attendant hasrlocatedgthe trunk which ,is giving the.y trouble; he noti,

nec-tion is releasedzthe'operator restores the kkey K to normal and tells the calling subscriber that he may proceed again to' callthe desirednumber int theusual ina-linen.:

i In case the observing operator suspects thatfthe speedof the subscribers calling-,I

device is too; high or too lou@ she may-.test

the speed yby operating tliefltey K which. connects a calling device speed indicator to: the operating lead. Sucha speedk indicator derail. in; the s.V raient switch C, Fig. 1.

1 vents a subscriber from setting up a des-ired connection lies in the line switch in which his line terminates. It the observing operator suspects that such is the case, she may operate the key K2, thereby disconnect'- ing the line switch C and connecting up another line switch to which the leads 71 and 72 associated with the key K2 are assumed to extend. This other line switch, of course, may be identical with the line If the operator observes that the calling subscriber always gets his number when this other line switch is connected up but not when the line switch C is connected up, shemay reasonably assume that the trouble lies in the line switch C, and may make a report to an attendant who will determine if her assumption is correct.

The various features of the invention having been described will now be pointed out in the appended claims.

What I claim is:

1. In an automatic telephone system, a plurality of subscribers lines, means including automatic numerical switches for setting up a connection from a calling one of said lilies to a called one of said lines, means for placing a certain line under observation, and means operated only during the setting up of a connection from the line under observation for displaying the number of the called line. Y

2. In av telephone system, a calling subsc-ribers line terminating at one end in a subscribers instrument and at the other end in an automatic switch, a plurality of other lines, means including said switch for setting up a connection between the calling line and one of said other lines, a` relay inserted in said calling line between the subscribers instrument and said automatic switch, and means controlled by said relay for displaying the number of the line with which the A calling line is connected.

3. In a telephone system, a plurality of subscribers lines, means including subscriber controlled numerical automatic switches for setting up a connection from a calling to a called one of said lines responsive to the calling of the digits in the numler of the called line, means for placing a certain line under observation, a digit space time recorder, and means for operating said time recorder whenever' a connection is being set up from the line under observation to another line.

4. In a telephone system, a plurality of subscribers lines, means including subscriber controlled numerical automatic switches for setting up a connection from a calling to a called one of .said lines responsive to the calling of the digits in the number of the called line, means for placing a cert-ain line under observation, a time recorder, means for operating said time recorder rendered effective whenever a call is initiated from the line under observation, and means for rendering said last named means inoperative during the calling of each digit in the number of the called line.

5. In a telephone system, a plurality of subscribers lines, means including sub-- scriber controlled numerical automatic switches for set-ting up a connection from a calling to a called one of said lines responsive to the calling of the digits in the number of the called line, means or placing a certain line under observation, a digit space time recorder, means for operating said time recorder whenever a connection is being set up :trom the line under observation to another line, and means tor rendering said last named means inoperative after the calling of the last digit in the number or the called line.

6. In a telephone system, a subscriber-s line terminating at the exchange in an automatic switch, means including said switch and other switches controlled by the subscriber on said line for extending a connec- -tion to another line, and means for automatiline terminating at the exchange in an auto- V mat-ic switch, means including said switch and other switches controlled by the subscriber on said line for extending a connection to another line, an operators position, and means tor automatically advising the operator at said position as to'which line in the exchange the said subscriber is connected with.

8. In a telephone system a subscriber-s line terminating at the exchange in an automatic switch, means including said switch and other switches controlled by the subscriber on said line for extending a connection to another line, an operatorie position, and means for displaying the -called number to the operator as soon as the connection is completed.

9. In a telephone system, a subscribers line terminating at the exchange in an automatic switch, means including saidswitch and other switches controlled by the subscriber on said line for extendingv a connection to another line, an operators position, and means for registering the digits in the line terminating at the'exchange' in an auto-vV matic switch, means including said switch and other switches controlled by theV sub-v scriber on said kline for extending'a connection to another line, a relay responsive to .all the digitsk of the callednumber, anda plurality of digit registering'devices con; trolled by Asaid relay. v

11. In a` telephone system, a subscribers line terminating at the exchange in van automatic switch, means including said switch and other switchesA controlled by the subscriber on said line for extending aconnec` tion to another line, a relay responsive tok all the digits of the called number, a plurality of digit yregistering devices controlled 'by said relay and a plurality of groups .of digit display lampscontrolledby said registering devices. y y

12. In a telephone system, a subscribers line terminating atthe exchange in an au tomatic switch, means including said switch and other switches ycontrolled the subscriber on said line for .extending a connection to another line, a relay responsive to all the digits of the called'number, means controlled by said relay for registering'the different digits, and means for-transmitting the complete number to an operator.

13. In a telephone system, a subscribers line terminating at the exchange infan .automatic switch, means including said switch and other switches controlled bythe subscriber on said line for extending a connec-` tion to another line, a relay responsive to all the digitso the called number, an opera-Y tors position, and means controlled by said relay for registering the complete number and for displaying the same `at said Vposi-` tion.

14. In a telephone system, a calling subscribers line, automatic switchescoiitrolled by the calling subscriber in accordance with the digits in a called number to extend a. connection to anotherline, and means at the exchange for making a record of the time intervals which elapse between the calling ot successive digits. 1 n

15. In a telephone system, acalling subscribers line, automatic switches controlled by the calling subscriber in accordance with the digits ina called number to extend a connection to another line, arecording device at the exchange forl registering the length of the time intervals which elapse between the calling of successive digits, and means for automatically starting said devicel when the call is initiated.

16. In a telephone system, a calling subscribers line, automatic switches controlled by the calling subscriber in accordance with lay, .and circuit arrangements for', shunting said relay responsive'to the said linebeing the digits in a called number to extend a connection'to another line, ajrecorder at the ex change `,comprising a movingl tape and means for marking the saine, means for bringing Asaid marking means-in contact with the tape vwhen .the call-'is' initiated, and means `for separating said marking means fromthe tape during the calling ot'each digit of the number. n

17. In a telephone system, a subscribers line terminating at the exchange in4 an automatic switch, means including said switch 1 and other switches controlled by the sub scriber on said line for extending a connection toanother line, an impulse senderat. the station on said line by means of which said switches are controlled,an op'erators position, means forr notifying the operator when the call is initiated, animpulse speed indicator, and meanswhereby the operator can cause saidindicator to be operated siinultaneously with said switches. Y

18; In a` telephonev system, a subscribers line .terminatingr at the exchange in' an au ltoniatic switch, means including said switch 'and other switchesY controlled 'by the; sub@A scriber on said line -for extending a connec-V tion to another line, an impulse sender at the` station on saidline by means ofwhich said switches are controlled, an` operators posi tion, means for notifying the operator when the call is initiated, and a speed indicator at the operators position for'indicating to the yoperator the rate at which impulsesfare transmitted tosaid switches. 19; In ay telephone system, a subscribers line terminating in an automatic switch for use Vwhen said line is calling, other switches` for connecting with the said line when'the same is called, a-relay connected in series with the said line between the subscribers station` and said first switch andoperated over the two sides of .the said linein series registering mechanismv controlled bysaid reconnected in a conversational circuitv either as a calling or a called`lline, said relay not being shunted when said line is a calling line and the desired connection is in process of being established.

20. In a telephone system, a line extend! ing'from a manual switchboard to an automatic switch, means including said switch and other Switches yfor extending connection to a called line, means for reversing the direction ot current flowl inthe vsaid line when `the called lsubscriber answers, an answering supervisory signal responsive to the reversal, another supervisory signal, and means for operating the other signal in case the vdirection of current flow in said line is reversed before the called line is conl nected with. Y

party line, an operators position and means for notifying the operator when the line is calling or being` called, said means serving also, in case the line is being called, for notifying the operator which of the severa parties on the line is wanted.

22. In an automatic telephone system, a subscribers line, subscriber controlled automatic switches for extending a connection to another line, an operators position, and means at said position individual to said subscribers line tor notifying the operator when the call is initiated, when the first directively controlled switch involved in the connection is operated, when the con`- nection is completed, and when the called subscriber answers.

Q3. In an automatic telephone system, a subscribers line, subscriber controlled automatic switches for extending a connection to another line, an operators position, and visual means for notifying the operator when the call is initiated, when each directively controlled switch involved in the connection is operated, and when the called subscriber answers.

2li. In a telephone system, a subscribers line extending by way of a manual switchboard to an automatic switch," means including said switch and other switches con trolled by the subscriber on said line for extending connections to cailed lines, means for notifying the operator when said iirst switch is out of order, another switch, and means at said switchboard whereby the opeator can substitute said last switch for said iirst switch to enable the subscriber to call. i

25. In a telephone system, a plurality of subscribers lines, means including sub scriber controlled numerical automatic switches for setting` up a connection from a calling to a called one ot' said lines responsive to the calling of the digits in the number of the called line, a time recorder, means for placing a certain line under observation and for connecting said recorder therewith, and means for operating said time recorder after the subscriber on the line under observation has responded to a call. f

26. In a telephone system, a protector on the distributing :trame at the exchange, a subseribers line normally connected through said protector and terminating in an automatic switch, a link circuit, and means for inserting` said circuit at said protector to include same in series with said line for observation or testing purposes.

27. In a telephone system, a protector on the distributing frame at the exchange, a subscriber-s line normally connected through said protector and terminating in an automatic switch, observation equipment including means for signaling an operator on calls incoming to and outgoing from said line, and means for inserting said equipment at said protector to include saine in series with said line for observation purposes.

28. In a telephone system, a protector on the distributing frame at the exchange, a

subscribers line normallyconnected through said protector and terminating in an automatic switch, a test shoe, a link circuit having both ends terminating in said shoe, said shoe adapted to be inserted into said protector to include said circuit in series'with said line, and means in said link circuit for enabling an operator to supervise incoming and outgoing calls to and from said line.

29. In a telephone system, a protector on the distributing frame at the exchange, a subscribers line normally connected through said protector and terminating in an automatic switch, a test shoe, observation equipment connected to said shoe via a tour conductor cord, said shoe adapted to be inserted into said protector :for including said equipment between the subscriber and said switch for Iobservation purposes.

In witness whereof, I hereunto subscribe my name this 10th day of Gctober, A. D., 1921.

WILLIAM A. BENSON.

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