US1245402A - System for observing telephone service. - Google Patents

Description

J. F. TOOMEY.

SYSTEM FOR OBSERVING TELEPHOUESERVICE.

APPLICATION FILED IAII.22. 1916.

1,245,402 Y Pateted Nov, 6, 1917.

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fr lnvehar: ini f J" Jah/1F Toomey Patented Nov. 6, 1917.

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J. F. TOOMEY.

, SYSTEM FOR oBsERvlNG TELEPHONESERVICE.

`APPLICM'ICIN FLED JAN.22,\916.

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JOHN F. TOOMEY, F NEW YORK, N. Y., ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPI-I COMPANY, A CORPORATION 0F -NEW' YORK.

SYSTEM Fon onsnnvme TELEPHONE snnvrcn specification of Letters raient.

PatentedNov. 6, 19'17.

Application leJ'anuary 22, 1916. Serial No. 73,648.

To all whom it may concern:

Be it known that I, JOHN F. TooMEY, residing at New York, in the county of New York and State of New York, have invented certain Improvements in Systems for Ob-A serving Telephone Service, of which the following is a specification.

ily invention relates to systems for observing the conduct of operators in the performance of their duties in connection with a group of telephone lines. It is specially directed to means in such a system tor informing an observer of acts connected with toll devices, as in collecting and refunding coins deposited at coin bozrsubstations and in recording calls upon a message register, to means for preventing disturbances in the observing circuit from being transmitted to the observed operator and to the adaptation oi observing systems for use with machine ringing apparatus.

In the accompanying drawings, Figure 1 shows the equipment individual to one of a plurality of substation lines, the service of which is to be observed, together with an operators cord circuit for coperation with said line; and Fig. 2 illustrates the apparatus common to all the lines of the observed group and individual tothe observingtrunk.

A line L of a group under observation appears terminating at an answering jack J and multiple jacks J at a central station A. Considering now the apparatus associated with the line L as typical of all the lines of the group, it has the usual line relav R and cut-ott relay R', the former controlling the line lamp Z and the latter having in parallel with it the service meter or message register m. At some convenient point, as the distributing` frame, there may be temporarily connected to the substation line, as is indicated at the terminals t, aser-vice observing line provided with the` initiating relays R2 and R3, which, energized successively as a result of the actuation of the line relay, start a train of operationsy leading to the connection of the line to the observing trunkY it' the latter isnot already joined to a line of the group, or its beingnlocked out therefrom if the trunk is busyl The energi- -zetie 0f relay R3 meri-ale@ be @fasted by im operators initiating relay RV4 which is parallel with vthe cut-oii relay. Vshen the secondary initiating relay R3 is energized in either or' the ways mentioned, it causes the trunk-seizing relays R5, R6 and R7 to become active, this bringing about the coperation of the line and disengaged trunk. A. sluggish lock-out relay R8, when energized as a. result of the trunk being in use, pre'- vents this appropriation of the trunk by the relays R5, RGV and R7. At t the conductors of the various service observing lines of the group are multipled to the conductors of. the service observing trunk, tive of which conductors, L2, L3, L4, L'5 and L, lead through to the distant observing station, which vmay be at another office B. Of these trunk conductors, L2 and L3 are talking andA the remainder controlling conductors. In the talking conductors is the customary .repeating coil I and a retardation coil D, the latter preventing the trunk from absorbing an undue vamount of energy from the line, and thus reducing transmission, yand also tending to shield the line against inductive disturbances originating in the trunk.

At the office A, individual to the trunk and therefore common to the lines under observation, is a. subscribers lrelay R9 operated by current over the observed line when the receiver is removed from its hoolr,`

this circuit being through the back contacts-r of quick-acting relays R90 and R91. Relay R90 is joined to the tip side of the trunk be; tween the winding 72 of a repeating coil I and the yusual condenser 0. Relay R91 is in parallel with condenser c, and has in series with it a condenser c so that it is operated onlyY by ringing current. Associated with the relays just mentioned are also a trunk relav R10 which determines whether the trunk-seizing or lock-out relays shallreceive current, repeating relays R10, R1@ which interrupt the direct conductive cornl tinuityfor" certain of the local conductorsof the observing trunk for reasonsI which will appear when the operation of the system is described in detail,'a register relay R152',

indication initiating relay putting Hin Q eii'evct the identification of the observed, lie, and indicator controller rlarett eed-'3% Relay R102 responds to the relatively high voltage employed to actuate the register' fm, and connects to the trunk an interrupter Q or other signaling means for indicating to the observer that the operator has registered a call. Relays R12 and R13, acting in succession in consequence ot the operation ot' relay R11, govern the holding magnet H, and through the stepping relay R14 tliemotor magnet. ill of an indicator controller S, which, as will later more clearly appear, controls the operation ot identifying the line under observation. This device S may consist ot the Well knoivn step-by-step automatic selector, in which a brush s is moved by ratchet mechanism c over fixed contacts s2 under the influence ot' the motor magnet M. A paivl s3 actuated by the holding inagnet H retains the brush in the position to which it is advanced, and ivhen this paivl is Withdrawn, a spring at returns the brush to normal. A test relay R15 responds through the brush s to an active condition of a particular terminal S2 and stops the advance of the operation by opening` the stepping circuit. Associated with opposite ends ot the trunk are observation limiting relays B160, R16, the action ot which, governed from the observers station, determines Whether an originating call, or one beginning with the closure of the hook switch at a substation, or a terminating call, started by insertion by the operator ot' the calling plug of a cord circuit in the jack of a called line, or both, shall be observed.V

rEhe operators position at central station A is equipped ivith a suitable number ot' cord circuits, the essential portions ot' one ot which are illustrated at C in Fig. l. Considering only the elements which more intimately concern .the present invention. there are the plugs 77 and 79 for respectively coperating with the'ansivering jack l ot' an observed calling line and the multiple iacks J of an observed called line. A key joins to the cord circuit a source ot current of a voltage higher than the talking` battery. say 89 volts. to actuate the message register m. Coin collect and refund keys 7o and k2 open the, cord conductors and respectively apply positive and negative high voltage current, which may be 110 volts. to the answering end of the cord todirect a coin deposited by a subscriber. either to the till ot the coin b'oX or to the ret'und chute. There is superimposed upon this steady current Jfrom both sources by means of the transformers T and T. intermittent current produced by interrupters (7 and (1 so arranged that they send out characteristic tones serving to indicate the application of the collecting and refunding current to the calling' line. An oplera'tors coin collect and refund signal o is controlled by relays r3 and r4, having their ings of the transformers T and T', respectively. rlie cord circuit is equipped with the customary machine ringing appa `atus which automatically transmits alternating current to the called line when the plug p is inserted in one of itsjacks.V This apparatus comprises an interruptor 72 through which alternating and direct current are alternately made available for ringing and tripping purposes through the agency of a ringingrelay r and tripping and locking relays r and r2.

it the observing end of the trunk at station E is a subscribers signal relay R" and an operators signal relay .R18 operated through front contacts of the repeating relays Rloo and R101, respectively. Relay R17 under the influence of relays B2 and R9 and relay R18 governed by relay R4 control .lamps or other signals l andl Z2, respectively shoW- ing by their illumination or nonillumination vvhethcr the hook sivitch at the substation oit the observed linel is closed or open, and Whether or not an operator has plugged into a jack of the line. There is also at the observing station anindicator S which may be practically identical With the controller S, except 'that in the present embodiment of the invention the brush S5 is movable into eneagement ivith a series of contacts 8G joined to a like series of lamps Z3, respectively corresponding to the lines of the observed group associated With the Unk. This indicator has a holding magnet motor magnet M', and stepping relay R1 correspondin.e` to the like devices of the indicator controller. with relays R20 and R21 performing j nerally similar functions to the relays iii and R13. A suitable pulsator, yvhich may consist of the self-interrupting relays R200 and R201, furnishes the stepping impulses to both. stepping relays. rl`he observer is provided With keys K, K and K2. T first Vwhen actuated joins the operators receiving'telephone to the line and controls certain relays ot the indicatingcircuit and, through controller relays R12 and R13 over the trunk. the lock-out relay RS. T he keys l and 'Z. When closed, respectively permit either an originating or a terminating call to be observed.

Considering the operation ot the system in detail and assuming the contacts ot' the keys K and K2 to be open and a call to originate upon the substation line L, the closure of the line. circuit at the substation incident to the subscriber taking doivn the receiver causes the energization of the line relay Whichat its frontcontact supplies current to illuminatev the line lamp Z, and also gives a circuit in parallel therewith throu/Chrthe Winding of primary initiating relay l?. and this in turn through its contact 1G completes 'a circuit'through the iovver Winding' of thel secondary initiating relay R3. Further assuming that there is n line of this group under observation and that the resting contacts oi the lock-out relay R8 are therefore closed, there is a circuit from Contact 11 orn relay R3 through contact 1:2 of

lock-out relay R8 and conductor 13 to the point. 14, then in parallel through the windings or' the trunk-seizing relays R5 and R6 to a point 15, on by way of contact 16 of relay it, the lead 1'? of the service observing line a d through the back contact 18 of trunk relay R10. The front contact 19 of relay l?? closes one break in thecircuit of the lock-out relay, whereby it would be operated in case the trunk were in use. This will more clearly appear later. The subscribers lamp Z at the observing station is now lighted as a consequence of the energi- 'f 'tion ot' relay R17, there being first a circuit through the front contact of relay R2, conductor 20, front contact 21 of relay R5, lead and winding of repeating relay R100. This closing` its front contact provides a second circuit on by way oi' conductor 80, winding` Q3 ot' the trunk repeating` coil l, trunk conductor L3 and winding of vrelay R171 the attracted armature otA this subscribers signal relay supplying current to the lamp Z. The observer therefore is made aware that call is awaiting observation upon the trunk and may depress her key K to unite her receiver to the talking conductors L2 and L3 at the contacts 24 and 25, and also makina contacts 26 and 27 for purposes which will hereinafter be described.

By opening contact 28 relay B5 removes a short circuit 29 from the windings of relay B7, preparing it for operation. At front contact 30 of this relay a. path for current to control the operators signal relay R18 through repeating relay R10? is made ready, this, however, awaiting the energization of the operators relay R". Contact 31 f t relay R5 joins to the point 14 in the parallel circuit of relays R5 andR6 an armature of controller relay R13, through which later battery may be applied independently ai? the connection through contact 12 of the lock-out relay RS. When relav R6 opero ated simultaneously with relay R5, it lockedv this pair of relays through contact 32, lead and winding of trunk relay R10 independently of the path through the back contact of the last named relay. This lead 33 normally. or when the trunk is not in use, is extended by conductor 34 through the resting contacts 35 of all the relays R6 of the group in series, but as this relation does not directly concern the present invention, it

'-^ will not be further consi dercd. Resting cont et 3G of relay RG in the path between the trent contact of trunk relay R10 and the windinfy ot' lock-out relay R8 is opened, this not being used when the trunk is idle, and said relay RS is joined at frontcontact 3 7 to lead 38 and the armature of observation limiting relay R16. rlhis allows the keys K and K2 when operated to exercise their control. r'it contact 35 of relay RG the connec tion between lead 33 and its extension 34l is broken, and there is substituted atk front Contact 39 a connection with a lead 40 eX- tending to a contact s2 ot the indicator conroller S, said contact being individual to the line which has seized the trunk. Battery is thus applied through the Winding of relay R10 to said contact.

When trunk relay R10 receives current through the locking circuit of relays R5 and R6, as already described, it operates and at its contact'41 completes a circuit through the winding of the indication initiating relay Rll and the normal contact 42 ofthe indicator controller S. Relay R11 attracts its armatures and at contact 43 locks itself independently of the controller contact 42, which will be opened as soon as the controller begins its advance. At contact 44 there is now a circuit by way of the winding of the primary controller relay R12, trunk conductor Le, contact 26 of key K, closed by the observer after the subscribers lamp Z lighted, conductor 46, through the normal contact 47 of indicator S and the .ifinding et the primary indicator relay R20. rllhe front contacts 48 and 49 of relays R12 and R20 thereupon cause the energization of the secondary indicator controller and indicator relays R13 and R21, respectively. At contact 49: the pulsator relays R290 and R201 are likewise started in operation. F ront contact 50 of relay R21 by short circuiting contact 47 provides for the continued energizatien of relay R20 after the indicator leaves its normal position. Contacts 51 and oi relays R13 and R21 close local circuits through resistances rc and ai for the holding magnets H and H', which apply the hawls a3 ot they indicator controller and indicator to the ratchet mechanism. There is also a circuit from the pnlsator relays R200 and R201 through front Contact 53 ofv relay R21, indicator stepping relay R19, conductor 54, contact 27 of Vkey K, trunk conductor L5, controller stepping relay R14, back Contact 56 of test relay R1? and front contact of relay R13, The relays R14 and R19 responding to the impulses make and break the local circuits of the motor magnets M and M, so that the indicator controller and indicator move forward the brushes s and S5 in synchronism until they former touches the Contact 82 belonging to the line which is connected with the trunk. Current thereupon flows through the winding or" relay R15, brush a, Contact s2, lead 40 of the service observing line, contact 39` of relay R6, lead 33 and Windingof relay R10. Test relay B15 severe the stepping circuit at contact 56 .stripping both the indicator controller and indicator. The brush ot the latter supplies current to the lamp Z3 corresponding to the line which is connected to the trunk, the illumination of said lamp informing the observer what line is under observation.

ln addition to rendering the holding inagnet ot the indicator controller active and closing a gap in the stepping circuit, relay R13 at Contact a5 through lead 45 gives a battery connection tor the circuit ot the parallel relays R5 and R0 from the point li, so that as long as relay R13 is maintained energized by relay R12 through the closure of the contact QG at the obseryers depressed key K, the trunk will be held regardless of the condition ot the relays R3 and RS, the contacts of which are included in the original energizine path.

After the line lamp Zliglited, the subscribers operator inserted the answering plug yi ot cord circuit C in the jack J, energizing the cut-ott relay R in the well known manner. The operators relay Rt receives current in parallel with this, and closing contact 57 provides for the continued energization of relay l?? by current through its upper winding after the path through the lower winding has been broken at contact l0 by the release ot relay R2, which is denergized when the cut-ott relay opens the circuit of the line relay. The circuit through the upper winding or1 relay B3 includes the winding of relay R7. rl`his operates and at contacts 5S and 59 closes through the talking leads 60 and 61 oi the service obserying line to the correspending trunk conductors L0 and L3, so that the observer may listen in. The talking leads having previously been maintained open, clicks and other disturbances produced up to this time by the action of the Various apparatus associated, inductively or otherwise, with the observing trunk will not get back into the line which is being observed. Contact 81 joins register relay R102 in parallel with the cut-oli2 relay and therefore with the register m, but being marginal relay R102 remains inert. The contact .57 also supplies current to the repeating relay R101 through lead 63 and contact 30 of relay R5. Relay R101 thereupon causes the energization of the operators signal relay R15 by way ot trunk conductor L2. winding 62 ot the repeating coil I and conductor 82. This displays the operators signal Z2 and the observer thereby knows that the operator has answered. The release of relay R2 would also cause the retraction of the armature of relay R100 and extinguish the subscribers signal Z', but the control of this is now transferred to relay R0, the -front contact 64 vof which supplies current to conductor L3. The energizing circuit ot relay R0 is through the back contacts of relays R00 .and R01, winding 89 oie the lat' ter, the Windes 72 0.5 .repeating ,Cell li. lead.

60, winding of the coil D, contact 58 of relay RT, circuit and the ring side of the line to battery at the cord C with which the operator has answered. Repeatingrelay R101, and also relay R100 previously referred to in connection with the display of the subscribers signal Z', assist in preventing various disturbances incident to the operation of the system, chiefly those induced in conductors of the service observing line and trunk from adjacent conductors, from being transmitted over the line and cord to the obseryed'operator. These relays completely interrupt the direct connection between talking conductors lf and L3 in which are included the windings of the signal relays R17 and R10 and the apparatus of the service observing line which control the operation of the last named relays, the relays R100 and R101 repeating effects from one section on the line to another and into the trunk. Because ot this, no current variations in the leads and 63 not strong enough to energize and deenergize the repeating relays can influence the trunk conductors L0 and L3. Moreover, because of the location of relays R100 and R101, permitting the conductors 8O and 82 to be of equal lengths and run together, and since there is no apparatus included in these conductors, their impedances may be kept equal. Consequently, any currents induced in the trunk conductors L2 and La, tending in their flow to ground through the front contacts of relays R100 and R101 to be transmitted back through repeating coil I over the observed line, will neutralize one anothers7 eii'ects in the windings QS and 62 of the coil, and will. not reach the observed operator.

it' the substation line, the service of which is being observed, is provided with a prepayment coin box, the operator having de termined whether or not connection can be obtained will depress either the key 7e or 762 in the cord circuit C. The one actuated. in addition to either collecting or refunding the deposited coin, will cause the tone produced by the interrupter g or Q to pass through the tip contacts of plug p and `iack J, Contact 5S of trunk-seizing relay R7, service observing lead 60, a winding of retardation coil D, back contact 83 of register relay R102, winding 72 of repeating coil I and the windings of relay R00 in series. T his will induce a like tone in the repeating coil winding 62 which will be communicated over the serv,

ice observing trunk tothe observers telephone. The observer will thereby be informed of the time and character of the act. It, instead, the .substation calling `and under observation were given measured` service, the operator when the wanted connection was obtained would close the contacts of the resistent-ey, Je. The.. current frere the :39H

tip side of the line, the substation.

volt source then ilows throughthe sleeve contacts of the plug p and jack' Jand is of suilicient strength to actuate the register m. It also energizes relay R102 by wayot iront contact 8l ot relay R7 and conductor 85. Contacts 83 and Sl of register relay R1"2 open the talking conductors of the trunk and at contacts SG and 8.7 connect the interrupter Q, in circuit with the windings 72 and S8 otl the repeating coil l'. Intermittent current induced in the associated windings ot the coil is communicated to the observers telephone so she knows that the call 'has been recorded. i

When at the close oi' the conversation the subscriber returns the receiver to its hook,' the opening of the substation circuit re'- leases the relay R0. This denergizes relay R11 and the subscribers lamp Z is extinguished. rlfhe withdrawal ot' theplug from the jack J by the subscriber-s operator in response to the supervisory signal in the cord leads to the deneroization of the cutotl relay and opens the circuit of relay R11. rhe latter breaking its contact 57 releases in turn relays R101. and R18 and the operators signal Z2 ceases to glow. rThe opening ot contact 57 also releases relays R3 and R1."

The Jfermer seyers the originating circuit of the relays R and R0 at contact ll, though these relays are still held up by relay R13 over lead t5. lVhen the observer frees the key K. it deprives the relays R12 and R20 of current by the interruption or" their circuit at contact 2G and they break the circuits of relays R13 and R11. rThese last named relays dcnergize the holding magnets H' and H and the indicator controller and indicator are returned to normal by their springs. Relay R15 'falls oil' when the brush of the indicator controller leaves the contact joined to lead 40. The opening ot contact ot' relay R13 releases relays R5 and R0, and the latter breaks the circuit of 'trunk relay R10 which releases relay R11. The observing system is now ready to take up another call.

rthe call upon the line of the observedv group might hare been terminating instead ot originating. That is, another subscriber may call for a line of the group, and therefore the rst operation in connection with it is the insertion otl a calling plug in one ot its multiple jacks J. Under such conditions the cut-oil'l relay R and the relay R4,-

in parallel are first operated. Contact 5T is closed by relay R* and relays R3 and R1 receive current in series, the former through its upper winding For a time relay R7 remains inert because ot' the presence of the short circuit Q9. As a result orp the making of contact 11 of relay R3. trunk relays R5.' and R0 are energized. and the display of the operators signal Z2 follows the closure of contact of relay R5 and operation of relays R101 and R18. The opening of contact 28er' relay R5 removes the short circuit from relay R7, which completes the talking leads. This,'it will be noted, follows the e'nergiza.- tion ofi-clays R5 and R0, so that the line is protectedfagainst sounds incident to their action andthe operator will be less liable to be made aware that she is being observed. Relay R0 renders trunk relay R10 active, and when the observer throws they key K various relays ot' the indicator controller 'and indicator will be energized and the vlamp Z3 ot the called line will be lighted by the indicator. .Relay R0 responds to the closure of the substation switch hook when the called subscriber answers, and operating relay l 11 lights the subscribers lamp Z at the observing desk. rl`he description of the release of the apparatus for an originatingV call is applicable to the present case.l

'llie calling end of the cord used in the previous connection haring machine ringing equipment, as has been described, with the winding of the subscribers relay R0 united directly to the trunk without interposed means Jfor preventing such an etlect, the low impedance path thereby offered to ground. would allow the operation ot relay r in the cord and the premature disconnection of ringingcurrent from the called line. .The circuit of this relay a" wouldV be thronghinterrupter g2, contact 88 ot ringing relay. r, tip contacts of the plug p and jackY J', con-k tact 58 of vrelay RT, service observing lead 6.0, winding` of the retardationcoil D, contact S3 ot' relay R102, winding 72 ot the repeating coil I and the winding of relayrR9 to ground. In the circuit of the present in-y vention, however, during the silent interyal, the direct tripping currentlflowing by way oit low resistance winding S9 of relay R00, contact 90 oit' said relay. contact 91 of relay R01 and winding of relay R0 ope'ates relay R00. severing the low impedance path previously traced at contact 90, so'that the tripping relay is not energized. Relay R00 maintains the attraction of its armature by current through itshigh resistance locking winding 92. This is not suiiicient to operatey the tripping relay. During the ringing interval the relay R01 in parallel with the con denser c' receives the alternating 4ringing current. which traverses the condenser c. Relay R01 attracts its armature and `by open, ing` contact 91 breaks the circuit ofthe trip-` ping relay. Interference with. the action of the machine ringing apparatus by the con-` nection of lthe observing system isl therefore entirely avoided.` l l TherelayR00 also performs a `functionin connection .with the operation of the coin box similar to that for the ringing annaratus. Were the path through relay R'fleft unbroken when 1l() yoltcurrentis ,applied4 tothe tip side of lthe line to actuate the coin the A box mechanism, it would constitute a low impedance connection for it and for the relays r3 and 114 controlling the coin box signal 0 which would interfere with their operation. `lVith the observing circuit as here organized, this current as just described energizes relay RQ0 to open this low impedance connection at contact 90 and substitute theholding connection of high impedance which will not affect either the coin boX or its signal relays.

In either an originating or terminating call, if the observing trunk had already been connected to a line when the subscriber on line L called or is called, the trunk relay R1o would be found energized.' Therefore, upon the operation of relay R3 associated with line L, instead of a circuit through back contact 18 for energizing the trunkseizing relays R5 and R6 there would be a circuit through front contact 41 by Way of lead 65, resting contact 36 of relay R6, conductor 66, resting contact 67 and Winding of lock-out relayV R8, resistance m2 and front contact 19 of relay R3. Relay R8 opening contact 67 locks up through contact 68, so that it will remain energized regardless of the condition of the trunk relay. At contact .12 relay R8 breaks the originating circuit for the trunk-seizinfr relays R5 and R6. Consequently, the line is locked off the trunk until a new call is made and the trunk is found idle. Since relay Rs isV slow to release and since its continued energization is through a chain of relays, a sutlicient time interval is given so that it will not release if the subscriber endeavors to attract the attention of the operator by making and breaking the contacts of the switch hook.

1 The proper maintenance of the lock-out is thus assured.

t may be desired only to observe one class of calls, say those originated by the subscribers upon lines under observation. In

such case the key K is actuated, joining fore described, there is closed at the front Contact a path for relay R160 through con-y tact 69 of key K. Relay R1G0 over trunk conductor L4 energizes the observation limiting relay R16. Relay R16 attracts its ar- 5 mature and completes a circuit for the lockout relay RS, this passing through conductor 38, front contact 37 of relav R, lead 66, resting contact 67 of relay RS, Windino` of said relay, resistance .m1, and front Contact 19 of relay R3. Relay R8 locks itself through contact 68 and opens at contact 12 the circuit of the trunk-seizing relays R5 and RG. r1`he former at contact 30 cuts olf the current from relay R101 and therefore from the operator-s lamp Z2 before the latter has time to glow, so the observer receives no signal. At contact Q8 relay R5 rapplies the short circuit 29 to relay R1, and this is denergized. The line is now held locked off the trunk until the call is completed, as in the case of an attempted connection with a busy trunk.

1f the call had instead originated upon the line, the operation proceeds as though Y the key K were in its normal position until the operator in answering inserts the plug in the jack of the calling line. This, provided the observer is occupied with some other line or for any reason fails to take up the call by depressing her key K, operates the relays R16 and R8 as just described, and the consequent release of the trunk-seizing relays R5, RG and R7 denergizes the relays Whose circuits are dependent upon them, eX- tinguishing the lamp Z and placing the trunk in a condition to take up another call.`

But if after seeing the illumination of the subscribers lamp. Z and before the operator answers the observer had closed the contacts of the key K, the indicator controller relay R12 Would be operated through key contact 26 and the secondary relay R13 in turn energized. At its contact 415 the latter closes the holding path for relays R5 and RG from point 14 by Way of contact 31 of relay R5 and lead Consequently, when relay R1G closes its front contact upon the response of the operator and the energization of the operators signal relay R1S and relay R160, although it Operates the lock-out relay R8, this produces no eifect because the holding path maintains the trunk-seizing relays actuated.

Vere terminating calls only to be observed, the key K2 would be thrown to close contact 71. The effect is similar to that just described, in the present instance the relay R1GO being operated by the subscribers signal relay R17 in parallel with the lamp Z through contact 91 of key K. This causes the relay RS to lock out all originating calls. Upon a terminating call, if the observer does not depress the key K before the subscriber removes the receiver from its hook in response to the passage of ringing current over the line following the plugging in with the calling end of a cord circuit by the operator, the attraction of the armature of the subscribers signal relay R17 will lead to the operation of relays R16 and R1G and the line which seized the trunk will be disconnected therefrom. On the other hand, the closure of Contact Q6 of key K gives the holding path `local conductors.

Having thus described my invention, I claim:

l. The combination with a line the service of which is to be observed, of a service observing system comprising observation controlling electro-mechanisms, conductors connecting the line and observing station, conductors for uniting the electro-mechanisms with one another and with the line, one of the conductors being in sections, and means for repeatingelectrical impulses from one of the sections to another, said means being responsive to the currents peculiar to service observation and irresponsive to disturbing currents.

i The combination with a line the service of which is to be observed, of a service'observing system comprising observation controlling electro-mechanisms, trunk concluetors connecting the line and observing station,l local conductors for uniting'` the electromechanisnis with one another and Wit-h the trunl-z conductors and line, one of the local conductors being in sections, and means for repeating electrical impulses Ji'roin one of the sections to another, said means being responsive to the currents peculiar to service observation and irresponsive to disturbing currents.

The combination With a line the service of which is to be observed, ot a service obser ing system comprising observation controlling electro-mechanisms, service observing trunk conductors connecting the line and observing station, conductors for uniting the electro-mechanisms with one another and with the trunk conductors and line, one ot the conductors being in sections, and electro-mechanical means for repeating electrical impulses from one of the sections to another, said means being energized by the currents peculiar to service observation and irresponsive to disturbing currents.

et. The combination with a line the service ot whicli'is to be observed, of a serice observing svstem comprising observation controlling electro-inechanisms, service observing trunk conductors connecting the line and observing station, conductors for uniting thc electro-mechanisms With one another' and with the trunk conductors and line, one of the conductors being in sections, and a relay having its Winding included in one of the sections and its contacts in another of Athe sections.

5. The combination with a line the service of Which is to be observed,l of a service observing system comprising observation controlling electro-mechanisms, trunkV conducductors connecting the lineand observing station and including talking conductors, local conductors uniting the electromechanisms with the talking conductors, and repeating apparatus included in said 6. rIhe combination With a line the service of which is to be observed, of a service observing system comprising observation controlling electro-mechanisnis, service observing trunk conductors connecting the line and observing station and including talking conductors, a local conductor uniting one ot the electro-mechanisms With a talking conductor and being in sections, and a relay having its winding in one section and its contacts in another section.

7. The con'ibination With a line the service of which is to be observed, ot' a service observing' system comprising observation controlling electro-mechanisms, service observing trunk conductors connecting the line and observing station and including talking conductors, a. local conductor uniting one of the electro-mechanisms with a talking conductor and being in sections, and repeating means between the sections interrupting their conductive continuity, the sections of the conductors between the repeating means and talking conductors being ot substantially equal impedance.

S. In a service observing system, a central station at whicn is an operators position, an observed line terminating at said position, a toll apparatus associated with the line, an observing station adapted to be connected With said line, and means depending upon the operation ot the toll apparatus for producing a signal at the observing station.

Spin a service observing system, a central station at Which is an operators position, an observed line terminating at said position, a toll apparatus associated with the line, an observing station adapted to be connected With said line, and tone generating means controlled with the toll apparatus for producing a signal at the observing' station.

l0'. in 'a service observing system, a cen-v tral station at vfliicli is an operatorls position, an observed line terminating. at said position.v a toll apparatus associated with the line,an observing station adapted to be con nected to said line, a connecting circuit for the line,`means included in the connecting circuit for controlling the toll apparatus,

and means dependent upon the actuation ot the controlling means for producing a` signal at the observing station.

li. In a service observing system, a central station ativliich is an operators position, ran observed line terminating at said position, a register connected therewith, a service observing station adapted to be connected With said line, and means for producing a signal at the observing station upon the operation of tne register.

l2.V In a service observing system, an observed line, a register connected therewith, a service observing station, a trunk joining the line' and serviceobserving station, means 'for producing a signal at' the observ- Ofi l ing station, and controlling means for the signal associated with the trunk, said controlling means being operated in the operation the register.

- 113. in a service observing system, an observed line, a register connected thereivith, a service observing station, a trunk joining the line and service observing station, means for producing a signal at the observing station, controlling means for the signal associated vvith the trunlr, and means for joining the line and trunk, said means also conneetin@n the register and controlling means and the controlling means being 0perable in the operation of the register.

la. in a service observing system, an observed line, a register connected therewith, a service observing station, a trunk joining the line and service observing station, means for producing a signal at the obser ring station, and a relay energized vvith the register and thereupon openinfy the trunk and connecting the signal producing means to the observing station.

15. In a service observing system, an observed line, a registerI connected therewith, a service obserifing station, a trunl: joining the line and service observing station, a relay energized with the register and control-1 ling the continuity of the trunk at its back. contacts, and a source of tone connected to the observing station through thefront contacts of the relay.

16. 1n a service obserY-.fing system, a central station at -which is an operators position, an observed line terminating at said position, a coin collecting apparatus connected with the line, an observing station adapted to be connected With said line, means for controlling the disposition of a coin and ymeans under the influence of the controlling means for producing a signal at the observing station.

1'. in a service observing system, a central station at which is an operators position, an observed line terminating at said position, a coin collecting apparatus connected With the line, an observing station ada ated to be connected With said line, controlling means for causing a coin supplied to the apparatus to be deposited or refunded, and a plurality of signaling` means for indicating at the observing station the operation of the controlling means.

18. In a service observing system, an observed line, a prepayment coin box associated therewith, a connecting circuit having denosit and refund keys, said keys applying current of dilferent characteristics to the line in the operation of the coin box, an observing station, and means at the observing station for transforming the currents into distinguishable signals.

19. ln a service observing system, an observed line, a prepayment coin box associated therewith, a connecting circuit having deposit and refund keys, sources of depositing and refunding current for the coin boX connected through the keys, means .for superposing di'erent tone producing currents upon the depositing and refunding current, an observing station, and means for communicating the diderent tone producing currents to the observer. y

20. The combination with a service observing station and a line to be observed, of a trunl; connecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk, and means for opening saidY path When currents possessing particular characteristics are applied to the line.

21. The combination with a service observing station and a line to be observed, of a trunk connecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk, and means responsive to current of relatively high voltage for opening the path.

The combination with a service observing station and-a line to be observed, of a trunk connecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk and a plurality of instrumentalities responsive to current of different characteristics to open the path. y

rihe combination `with a service observing station and a line to be observed, of a trunlrconnecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk, and a plurality of instrumentalities responsive to alternating and direct curren to open the path.

24. The combination With a service observing station and a line to be observed, of a trunk connecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk, and a relay having its vvindingconnected to the trunk and a contact in said path.

25. The combination With a service observing station and a line to be observed, of a trunk connecting the line and station, observation controlling apparatus, a path for current through the observation controlling apparatus joined to a conductor of the trunk, and a relay having a low resistance Winding and a high resistance locking winding, the low resistance Winding being included with the relay contacts in said path.

26. The combination with a service observing station and a line to be observed, oi

a trunk connecting the line and station, obname to this specication in the presence of servation controlling apparatus, a path for two subscribing Witnesses, this 18th day of current through the observation controlling January, 1916. y

JOHN F. TOOMEY.

trunk, and means responsive to alternating Witnesses:

apparatus joined to a conductor of the current for opening the path. ALFRED KAUFMANN, In testimony whereof, I have signed my STANLEY FAIRCHILD.

Copies o! this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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