US1243749A - Measured-service telephone system. - Google Patents

Description

T. G. MARTIN. MEASURED SERVICE TELEPHONE SYSTEM.

Pabented Oct hum/701?.-

M/[T/YESSES T. G. MARTIN. MEASURED SERVICE TELEPHONE SYSTEM. APPLICATION FILED DEC.26, 19:3.

1,243,749.. Patented 00. 23,1917.

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' TALBOT e. MARTIN, on CHICAGO, ILLINOIS, ASSIGNOR To AUToMAT c'ELEoTRIc COMPANY, or GEICAGQ, ILLINOIS, A CORPORATION or ILLINOIS;

MEASURED-SERVICE TELEPHONE SYSTEIVL To all whom it may concern) Be it known that I, TALBOT G. MARTIN,

a citizen of the United States of America,

phone Systems, of which the following is a specification.

My invention relates to improvements in measured service telephone systems, and more particularly to improved means for recording the actual time during which a talking connection between two subscribers stations is established. I

More particularly my invention relates to a time recording mechanism which is controlled by a clock mechanism so as to be intermittently operated at predetermined intervals of time, this recording mechanism being started in operation by the response of the called subscriber and the operation being stopped when the connection is .released.

My present invention provides means for operating the meter by means of a reversal of current over the conductors of the talking circuit upon the response of the called subscriber. 7

My invention will be more clearly understood by reference to the accompanying drawings, in which, for the purpose of illustration, I have shown my invention in connection with an automatic telephone system of a well-known type, although, of course, it will be understood that my invention is not in any way limited to use in connection with any particular type of telephone system.

Figures 1 and 2 taken together show a complete circuit connection between a call-' ing substation A and a called substation A in a system embodying the principles of my invention. I

The central oflice equipment shown herein comprises only the socalled line switches and connector switch, but it will be clearly understood by those versed in the art that so-call'ed selector switches may be inserted in the system, thereby increasing the capacity of the exchange without departing from the principles of my invention.- The said selector switches may boot a type similar to the selector switches shown in British patent to T. G. Martin No. 1419 of 1910.

'The substation A shown herein may be Specification of Letters Patent. Patented Oct; 23 1917,

Application filed December 2c, 1913. Serial No. 808,852. l

of any suitable or approved type and comprises the usual receiver 2, transmitter 3, ringer 4 and condenser 5. Being a so-called automatic substation it is also provided with an impulse transmitter or calling device, which is herein represented by a pair of impulse springs 6 and 7 and an impulse wheel 8, which latter is assumed to be controlled through the medium of a finger hole d1al (not shown) in such a manner that the impulse springs 6 and 7 may be momentarily separated a number oftimes corresponding to each digit of the number to be called.

The subscribers individual switch C is of the general type of subscribers switch shown in British patent to R. W. James No. 26,301 of 1906, being, however, of the particular type disclosed in the above-mentioned British Patent No. 1419 of 1910. This line switch comprises, among other details, a plunger (not shown) attached to the end of a so-called plunger arm-1O which is controlled by the magnet 11. The magnet 11 comprises four windings, namely, a pulldown winding 12, a cut-off or holding Wind'- ing 13, a line winding 14 and an auxiliary winding 15. The core of the magnet 11 is so constructed that the magnetic circuit of the windings 12 and 13 is separatefrom that of the windings 14 and 15. The winding 12 operates both the plunger arm 10 and the cut-off armature 16, while the winding 18 is only strong enough to operate the-cut ofl armature 16 and to hold the plunger arm 10 in its operated position. When the plunger arm 10 is operated, the plunger is f forced into a bank of contact springs, forcing the springs 17 18, 19 and 20 into engagement with the springs 21, 22, 23 and 24, respectively. Although only one set of springs (17 to 24) is shown, each ,line switch is provided with a" plurality of such sets, each set forming the terminal of a trunk line leading to a connector switch H. Each trunk line isv connected in multiple with the corresponding springs of all the line switches British Patent No. 1419 of 1910. The function of the master switch, as is well known, is to maintain the plungers of all the idle line switches in position to engage the terminal of an idle trunk line.

The connector switch H is of the same general type of connector switch asdisclosed in United States Letters Patent No. 815,176, granted March 13, 1906, 'toKeith, Erickson and Erickson, the circuits, however, being modified to adapt the switch to operate in a system in whichthe central oiiice apparatus is controlled by impulses delivered over the two sides of the line in series. The connector is provided with a shaft (not shown) car- I in the wi ers 25 26 and 27 which shaft is controlled by the vertical magnet 28 and the rotary magnet 29. The usual side switch comprising the wipers 30, 31, 32 and 33 is controlled by the private magnet 34: in the usual well-known manner. The magnet 19 is the usual release magnet. The line relay 35 is connected with the calling line through the reversing springs of the so=called backbridge relay 36. The ringing relay 37 is the means through which ringing current is applied to the called line.

The called substation A, togetherwith its individual switch C, is similar in all respects to the substation A, together with its individual switch C.

For the purpose of supplying battery current for operating the central oilice apparatus and for talking purposes there is shown a battery 13 having one terminal grounded. The usual busy signaling machine is shown at L.

Associated with ,theline switch C of ,the calling line is a time recording meter M controlled by the meter magnet 72. The1cir cuit of this .magnet is in turn controlled by the meter relay 50 and by a clock mechanism K. This clock mechanism is arranged so as to intermittently open and close the contacts 51 and 52 and in this manner control the connection of the magnet 72 to battery B. The relay 50 is a double-wound relay, the windings being so proportionedthat it requires the energizationof both windings in the same direction to attract its armature,

said armature being unaffected by the energization of either winding alone, or by the energization of the two windings in opposition to each other. By this arrangement, when the meter relay 50 is operated upon the response of the called subscriber, in a manner to be hereinafter described, to close the circuit of the meter magnet 7 2, the clock i mechanism .1: then operates to intermittently operate the magnet 72 and thus cause the meter to accurately register the time consumed by the established connection.

A general description of the apparatus having been given, in order to give a complete understanding of my invention I will now describe how the calling subscriber at the substation A may obtain connection with the subscriber at the called substation A, and how the meter M will operate to regis ter the length of time that the conversation is held. It will be assumed that the number ofthe called substation is 20.

Upon the removal of the receiver from the switch hookatthe substation A preparatory to making a call, an energizing circuit is closed through the line winding 14; ofthe individual switch C, thereby attracting the line armature 38. The armature 38, upon being attracted, closes a circuit through the pull-down winding 12 in series with the auxiliary winding '15. The pull-down winding 12, upon energizing, attracts the plunger arm 10 to force the plunger into the bank of springs 17 to 24, inclusive. It also operates the cut-oii armature 16, thereby disconnecting the line winding 14 from the-line. The armature 38 does not fall back immediately, however, owing to the fact thatthe winding 15 is still in series with the pull-down winding 12. Upon the plunger arm 10 being attracted, the springs 39 and 40 are brought together to short-circuit the auxiliary winding l5, making the same slightly slow acting. At the same time the springs 39 and 10 make contact, the springs 41 and 42 are brought together, closing a circuit through the right-hand windingof the relay 50, said circuit extending from ground G through the saidwinding and the contact of springs 41 and 4:2 to battery B,=thence through cattery B ,to ground G; but the armature of the relay 50 is unaifectedby the energization of this winding alone. The armature 38 being slow to fall back allows sufficient time for a holding circuit to be closed in the switch ahead for the cut-oil or holding winding 13. The en agement of the springs 17 and 20 with the springs 18 and 21, respectively, extends thesubseribers lines to-the line relay 35 ofthe connector 'E.

This circuit extends through the left-hand winding of-the magnet 50, but does not operatively energize said magnet, as the two windings are acting in opposition to each other. The line relay 35 of the'conneetor switch E is thereupon energized, closin a circuit through the slow acting relay 43. The relay 43, upon energizing, closes the above-mentioned holding circuit through the cut-off winding 13 of the line switch C. This circuit extends from ground G through the contact of springs 4%, bank springs 22 and 18 and'the cut-off -winding"13 to battery B. The winding 13, upon energizing, holds the cut-off armature 16 and the plunger arm 10 in their operated positions after the circuit of the pull-in winding is broken by the falling back of the iine armature 38. A guarding ground potential is supplied to the connector private bank contacts of the calling line as soon as the relay 43 isenergized. This potential extends over the circuit just traced to the bank contact 18, thence over the conductor 45 to said private bank contact. The energization of the relay 43 also prepares a circuit for the vertical magnet 28 by bringing into engagement the springs 46 and 47 and opens the circuit of the release magnet 49 at the springs 47 and 48.

The calling subscriber now operates his calling device for the first digit 2 of the called number, whereby the substation impulse springs 6 and 7 are operated twice -momentarily, each time breaking the circuit of the connector line relay 35. The relay 43 of the connector switch being slow acting does not deenergize during the momentary interruptions of its circuit by the line relay 35, and consequently, each time the latter relay deenergizes, an impulse is transmitted over the circuit extending from ground G through the contact of springs 55 and 54, springs 47 and 46 of the relay 43, slow acting relay 57, vertical magnet 28 and the side switch wiper 30 (in first position) to battery B. The vertical magnet receives two impulses over this circuit and operates to raise the switch shaft and wipers to a position opposite the second level of bank contacts. The relay 57, which was included in series with the. vertical magnet, remains in its energized position during the entiretime that impulses are being transmitted through it and operates to close the circuit of the private magnet 34. This circuit extends from ground G4 through the contact of springs 60 and 58 and the said relay to battery B. After the last impulse is delivered, the relay 57 opens the circuit of the private magnet 34, which, upon deenergizing, permits the side switch to advance from first to second position in a well-known manner.' The movement of the side switch wiper 30 from first to second position transfers the battery connection from the ver-- tical magnet 28 to the rotary magnet 29. The calling subscriber now operates his calling device for the last digit 0, in response to which the connector line relay operates to transmit ten impulses through the rotary magnet 29 in series with the relay 57, whereby the shaft and wipers are rotated onto the I contacts of the desired line. This circuit extends fromv ground Gr through the contact of springs 55 and 54, springs 47 and 46, relay 57, springs 61, rotary magnet 29 and the side switch wiper 30 (in second position) to battery B. If the called line is idle, the private magnet 34 deenergizes when its circuit isbrokenby the relay 57 after the last. impulse 'is delivered to the rotary magnet 29. The deenergization of the private magnet 34 allows the side switch to advance one more posit1on that1s, from sec-n the energization of the bridge-cut-ofi winding 62 of the line switch C, the connection is completed withthe' called substation. The circuit for the bridge-out-off ,winding 62 of the line switch Gextends from ground G through the side switch wiper 31 (in third position), private wiper 26, conductor 63 and the said cut-off winding to the battery lead 100. ergizing, operates to disconnect the line winding 64 of the line switch 0. from the line and to extend the line through to the called substation A. A guarding ground potential is supplied to the connector private bank contact of the called line, which prevents the called line from being seized by some other connector switch. By the engagement of the side switch wiper 30 with its third-position contact point, the circuit of the ringing relay 37 is closed. Thiscircuit extends from ground G through the interrupter 65, relay 37, springs 66 and the side switch wiper 30 (in third position) to battery B. The ringing relay, upon ener gizing, disconnects the called linefrom the calling line and bridges the ringing generator R across the called line. The ringing relay is energized only intermittently through the medium of the interrupter 65.

Upon the response ofthe called subscriber his line is provided with talking current through the back-bridge relay 36. The relay 36, upon energizing, closes the circuit of the ringer cut-off relay 67. This circuit extends from ground G through the side switch wiper 31 (in third position), contact of the springs 68 and the relay 67 to battery B. The relay 67, upon energizing, interrupts the circuit of the ringer relay 37 at the springs 66 and closes alocking circuit for itself through the springs 70 independent of the springs 68. A further result of the energization of the back-bridge relay 36 upon the response of the called subscriber is. the reversal of the connection ofthe windings of the line relay- 35 to the conductors 84 and 85, whereby the direction of the current in the calling line is re versed, and consequently in the left-hand winding ofthe relay 50. This reversal of current in the left-hand winding of the res. lay 50 causes thetwo windings of this relay to now assist eachother and to operatively energize the said relay, which upon energizing, closes the circuit for the meter magnet 72 and closes the contact of springs 71, whereby the left-hand winding of said'relay is short-circuited. The relay is then held in its operated position by thev righthand winding alone, which, although it is not strong enough to operatively energize the relay, is strong enoughto hold'it when The said winding, upon en 1.

inits operatedposition, The short-circuiting: of the left-hand winding renders the meter magnet inoperative to any changes in the line current. The said circuit for the magnet 72 extends from ground G through the'contact of springs 73,:met'er magnet .72 and the springs 51 and 52- (controlled by the clock K) to battery B. Thismaster' clock K operates to intermittently openthe springs 51 and 52 and this causes the intermittent operation of the meter M; The clock being adjusted so as to close these springs at predetermined time interva-ls,the meter operates to accurately register the time of the talking connection.

After the conversation is completed, the connection is released by the hanging upof the receiver at the calling substation in the usual manner and the magnet 50 deenergizes and the circuit of the meter magnet 72 is opened 1 at, the spring 73.

If the called line is busy, there will be a guarding potential upon the connector private bank contact, just as explained in connection with the line switch C. When the connector private w1per'26 engages this guarding contact,a busy signal is sent back to the calling line from the busy signaling machine L inthe well-known manner. The subscriber, hearing the busy signal, replaces his receiver upon the receiver hook and thus releases the apparatus.

It will thus be seen that I have devised a very simple and ei'licient' arrangement for measuring the length of time that a conversation is carried on. It will also be seen that the calling subscribers register begins to operate only when the called subscriber responds, so that the subscriber is not charged with the time taken to set up a connection,

or for the called subscriber to answer, but

is charged only from the time that conversation begins.

While I have illustrated the registering devices associated with automatic switches in connection with an automatic telephone exchange system of aparticular type, it is, of course, understood that my invention is not limited to use in such a system. The

registerim device may be employed with any suitable automatic system, and in its broader aspect my invention may be employed in connection with either manual or semi-automatic systems.

What I claim as my invention is 1. In a telephone system, a plurality of subscribers lines, means for establishing lation of said last=mea nsto thetalkingcir cuit, another winding for said means controlled over acircuit individual to the calling line, and aclock mechanismfor further controllingthe operation of saidmeter.

2. In a telephone system, aplurality of subscribers lines, means for establishingi connection between t wo'of said lines, a time recording meter associated with the' ca-lling i line, means for reversing the current in the; calling line upon the response of the called subscriber, means having a winding in se' ries withthe talking circuit conductors, controlled by said reversal of current for initially operating saidmeter and for changing the relation of said last means to the talking circuit, another winding for said means controlled over a circuit individual to the calling line, and a clock mechanism for intermittently operating said meter at predetermined time intervals after saidfirst operations 3. In a telephonesystem, a plurality of subscribers lines, means for establishing connection between-two of said lines',.a-time recording meter associated with the calling line, a relay for controlling the operation of said meter, said" relay'having a plurality of energizing windings,1neans for initially energizing said windings diflerentially when connection'is being extended to the called line, me'ans for reversing'the current in one of said windings upon the response of the called subscriber to-thereby render said relay operative to 'operate' said meter, a holding winding for said relay controlled over a circuit individual to'thecalling line, and a clock mechanism for further intermittently con'trollingtlie operation of said me ter'.

li In a telephone system, a plurality of subscribers lines, means including" automatic selecting and connecting switches for estabfishing connection between'two "of said lines, a time recording meter associated with the callingline, means for reversing'the current in the calling line upon the response of the called subscriber, means having"- a winding in series with'the talking circuit conductors controlled by said reversal of current for initially operating said meter and for chang ing the relation of said last means to the talking circuit, a holding Windingfor said means individual to the calling line, and a clock mechanism* for intermittently operating said meter at predetermined time I in tervals after said first operation.

'5.-ln' a telephonesystem, a plurality of subscribers lines, means for establishing" a talking circuit between-tweet said lines, a time recording meter associated with the calling line, a relay for c'ontrolling the operation of said meter, said relay having a plurality of energizing= w'indings, one of said windings beingin series "with" said talking circuit, and another of said windings being permanently connected to one terminal of battery, means for initially energizing said windings differentially when connection is being extended to the called line, means for reversing the current in one of said windings upon the response of the called subscriber to thereby render said relay operative to operate said meter, a clock mechanism for further controlling the operation of said meter, and means for deenergizing said relay to render said meter inoperative when the connection is released.

6. In a telephone system, calling and called subscribers lines, a time recording meter individual to each. calling line, means for establishing a talking circuit between two of said lines comprising an automatic switch individual to a calling line and an automatic switch common to the calling lines, a relay for controlling the operation of said meter, an energizing winding for said relay controlled exclusively over a circuit local to said individual switch, another energizing winding for said relay including a portion of the talking circuit controlled by said common switch to thereby control the operation of said meter, and a clock mechanism for further controlling the operation of said meter.

7 In a telephone system, calling and called lines, a time recording meter individual to each calling line, means for establishing a talking circuit between two of said lines comprising an automatic switch individual to the calling line and an automatic switch common to the calling lines, a relay for controlling the operation of said meter, a winding for said relay energized over a circuit exclusive of said common switch, another winding for said relay con trolled over a portion ofsaid talking circuit, by said common switch to thereby control the operation of said meter, and a clock mechanism for further controlling the operation of said meter.

8. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines including a link common to said lines, a time recording meter associated with the calling line, a relay for controlling the operation of said meter, said relay having a plurality of energizing windings, means for initially energizing said windings differentially when connection is being extended to the called line, means for reversing the current in one of said windings upon the response of the called subscriber to thereby render said relay operative to operate said meter, one of said windings controlled over a circuit exclusive of said link, and a clock mechanism for further controlling said meter.

Signed by me at Chicago, Cook county, Illinois, this 15th day of December, 1913.

TALBOT Gr. MARTIN.

Witnesses:

HARRY E. HERSHEY, B. GARBER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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