US1159855A - Special-service telephone system. - Google Patents

Description

v T. e. MARTIN. SPECIAL SERVICE TELEPHONI SYSTEM.

IVPLICAVTION FILED IA-YII- I912- 1,1 59,855. Patented Nov. 9, 1915.

- 3 HEE'ISSHEETI. I II L2 7 5% {I VL/JTNESSES MENTOR:

T. G. MARTIN.

SPECIAL SERVICE TELEPHONE SYSTEM.

APPLICATION FILED nun. Hill.

1, 1 59,855. Patented Nov. 9, 1915.

3 SHEETSSHEET 2.

W/T/VE5555 mum/70K.-

TTOR/YEYS.

T. G. MARTIN.

SPECIAL SERVICE TELEPHONE SYSTEM.

. APPLICATION FILED IAYH, 19l2.

1,159,855. Patented Nov. 9, 1915.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

TALBOT G. MARTIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SPECIAL-SERVICE TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Nov. 9, 1915.

To all whom it may concern:

Be it known that I, TALBOT G. MARTIN, a citizen of the United States of America, and resident of Chicago, in the county ofCook and State of Illinois, have invented certain new and useful Improvements in Special Service Telephone Systems, ofwhich the following is a specification.

Hy invention relates to special service telephone systems, and comprises an ar-. rangement of circuits whereby the subscribers of a telephone system, either manual or automatic, may be automatically supplied with music, news or information of any kind from a central distributing source. In order to accomplish this result I provide a loud speaking telephone receiver which may be bridged across the subscribers line, and at the central station I provide a special transmitting circuit which is bridged across the line, and thus the subscriber, by merely operating a key, or throwing a switch in some other manner, can connect his loud speaking receiver directly with this special transmitting circuit. I likewise provide means whereby, when a subscriber wishes to establish connection with some other subscriber, this special transmitting circuit is automatically disconnected from the line, so that it does not in any way interfere with the establishment of such connection.

My invention is adapted for and associated with either an automatic or a manual line. In connection with the automatic system I provide means whereby the special service circuit is automatically disconnected as soon as a subscriber removes his receiver from the hook preparatory to making a call. I also provide means whereby the circuit is disconnected when a connector switch connects with a line. In connection with the manual system, however, this special service circuit is automatically disconnected by the operator plugging into the jack of the line, whether this line he a calling or a called line.

These and other objects of my invention will be more readily understood by reference to the accompanying drawings, in which similar reference characters refer to similar parts.

Figures 1, 2 and 3 show a complete connection between a calling substation A (Fig, 1) and a called substation A (Fig. 3) in a system embodying the principles of my innormally vention. In Fig. 1 there is represented an automatic substation A to the line conductors of which there is allotted at the central oiiice an individual or line switch C. Q At D there is shown a master switch for controlling a group of line switches C. All the line switches of this group have-common access to a number of trunk lines which lead to first selector switches, one of which is represented at E in Fig. 2. A number of first selectors have common access to a plurality of second selectors, one of which is represented at F. The second selectors in turn have ac cess. to connector switches, one of which is shown at H in Fig. '3, by means of which connections may be completed with the subscribers lines. Figs. 4 and 5 represent diagrammatical modifications of the circuits, which will be fully described hereinafter. Fig. 6 is a diagram showing how my invention may be applied to a manual telephone system.

The automatic substations A and A may be of any suitable orapproved type. Those with which I have chosen to illustrate my invention, and as illustrated at A in Fig. 1, comprise the usual receiver 25, switch hook 26, transmitter 27, ringer 29 and condenser 30. In addition, the substation Ais provided with the impulse springs 31 and 32 and an impulse wheel 33. The impulse wheel 33 carries upon its periphery the impulse teeth 34 and is secured to a shaft 35, to which latter there is also attached a dial (not shown) provided with finger holes, through the medium of which holes the impulse wheel may be rotated. As the impulse wheel is returned to normal position by a spring (not shown) after it has been rotated' for any digit,each of the teeth 34 which passes the end of jthe spring 31 forces said spring out of engagement with the spring 32. The number of times these springs are separated depends upon the digit called. The substation A is also provided with a loud speaking receiver 2 which maybe of any suitable type. This receiver is normally disconnected from the line, but may be bridged across the line conductors 98 and 99 through vthe condensers 3 and 4: by means of the manually-operated key K.

The line switch C, which is individual to the line of substation A, and the master switch D are modified forms of the general typeof line switch and master switch disclosed in British patent to R. W. James No. 26,301 of 1906, the master switch D, however, being of the particular type shown in British patent to T. G. Martin No. 1419 of 1910. The line switch. C is a slightly modified construction of the particular type of line switch shown in said British Patent No. 1419 of 1910. As shown herein, the usual plunger arm 5 and cut-ofi armature 6 are controlled by a double-wound magnet 7 Of the two-windings upon this magnet only the winding 8 is strong enough to attract the plunger arm 5 from its normal position, while the winding 9 can. only attract the cut-ofi armature 6 from its normalposition, but can hold the plunger arm 5 in its operated position after it has once been pulled down by the winding 8. The usual line relay, instead of comprising a single winding upon the same core as the pull-down and cut-0E windings 8 and 9, as is shown in said British Patent No. M19 of 1910, in the present instance comprises an entirely independent doublewound relay 10. This relay is preferably slightly slow acting. Connected in multiple with the line relay 10 of the line switch C, and therefore normally bridged across the line of the substation A,

there is the secondary winding-of an induction coil 11. Condensers 13 and 1 1 are inserted in this bridge on either side of the induction coil. The primary winding ofthe induction coil is included in the local circuit with the battery B and thetransmitter 15. This transmitter is of suitable character to operate in conjunction with the loud speaking receiver 2 at the telephone, and may be simply a transmitter to be spoken into by an exchange attendant or other person, or may be controlled by a phonograph or in any other manner to transmit any kind of message that may be desired to be transmitted to the substation through the medium. of the loud speaking receiver 2. The selector E is of the general type or. selector disclosed in United States Letters Patent No..815,321, granted March 13, 1906, to Keith, Erickson and Erickson, bein modified, however, as shown in. said British Patent No. 1419 of 1910 so as to operate in a two-wirefsystem, z. 6., a system in which the'central oflice apparatus is controlled from the calling substation over the two sides of the line in series. The selector F is similar to the selector E, with the addition of the side switch". wiper 85. As the specific structure of these but, like the selectors, is modified in order to operate in atwo-wire system. Like the selectors, the connector is provided with a shaft (not shown) carrying the Wipers 86, 87 and 88 and is controlled by the vertical magnet 89 and the rotary magnet 90. The usual side switch is controlled by the private magnet 91 in the usual manner. The connector is provided with a so-called back- -bridge relay 177' through which the called substation is provided with talking battery current, and with a ringer relay 164 through the medium of which ringing current may be applied to the called line after connection is completed therewith.

The substation A and the line switch C are similar. to the substation A and the line switch C, respectively. With the line switch C there is not shown a transmitting circuit similar to that'comprising the transmitter 15 and induction coil 11 shown in connection with the line switch C, but, instead, there is shown a jack J which is normally bridged across the line through the medium. of the condensers 17 and 18. With this arrangement a transmitting circuit similar to that shown in connection with the line switch C (Fig. 1) may lee-provided with an ordinary plug, and may be connected with or, disconnected from the line at will through the medium of the jack J.

At M there is shown a ringing current generator and at L a busy signaling machine is shown comprising a current interrupter 93 and an induction coil 94 F or operat ing the central oilice apparatus and for furnishing talking current there is provided a battery B having one pole, preferably the positive, grounded at G.

Having given a general description of the apparatus 1 will explain in a general way the operations by which connection may be established between two automatic substations in the system shown. For example, it will be explained how the substation A may obtain eonnectionwith the substation A, the number of which latter is assumed to be 2220. When the calling subscriber re- 'moves his receiver preparatory to making.

a call, the switch hook rises, permitting the the spring 97 and into contact with the spring 96, whereby th'e circuit of the ringer 29 and'thecondenser 30 is broken and a bridge consisting of the substation transmitter and receiver is closed across the line conductors '98 and 99. j The closure of this bridge across the line completes an energizing circuit through the line relay 10 of the switch C. lhis circuit extends from ground G through theupper winding of the relay 10, springs 101 and 102, line 99, springs 95 and 96, 32 and 31, receiver 25, transmitter 27 line 98, springs 194; and 105 and the lower winding of the relay 10 to the battery lead 100, thence through battery 13 to ground G. The energization of the relay 10 serves to close the circuit of the operatlng winding 8 to cause the line switch to operate in the usual and well-known manner to select an idle trunk-line leading to the first selector E. The. winding 8, upon energizing, besides attracting the plunger arm 5 to causethe connection to be extended to the selector, also attracts the cut-ofl? armature 6, which not only disconnects the line relay 10 from the line, but also disconnects the sec-' twice momentarily. Each time the springs 31 and 32 are separated, the energizingcircuit of the line relay 77 of the selector E is broken, allowing said relay to be momentarily deenergized. This operation of the line relay77 causes the vertical magnet 16 to operate to raise the switch wipers 67, 68

and 69 -to a position opposite the second level. .These wipers are then rotated automatically to selectthe first idle trunk in this second level, which trunk leads to one of the second selectors F. Connection is thus extended-to the second selector. The-calling subscriber now operates his calling device for the second digit 2. The secondselector F operatesinresponse to the impulses for this digit in the same mannervas the selector E and extends connection to an idle con nector H over the trunk lines 134 and 135; The calling subscriber now'operates his dial for the thirdadigit 2, momentarily separat same manner'asi described for theffirs't digit.

Each time the impulse springs are separated for the third'digit, the energizing circuit for the connector line relay 92 is broken momen}; tarily. A This operation of the line relay op:

era'tes the connector in the well-known-manner to raise :it up-to the second level. The

connector isthen'in position to receive impulses for theilast digit 0. The operation of the substation calling device for this digit breaks the energizingcircuit of the relay 92.; ten times; 'The rotary magnet 90 then receives ten impulses and operates to rotatethe wipers ten steps, onto the contacts ofthe relay 149 is not open long enough to permit.

line No. 2220., The private magnet relay 149 is energized by the firstimpulse to the ro-' tary magnet and again closes the circuit of the private magnet 91'. The circuit of the it to, deenergize until after the last impulse has been delivered to the rotary magnet.

The relay 1 19'then deenergizes and breaks the circuit of the private magnet 91, which, if the called line is not already busy, in turn denergizes and permitstheside switch to pass to third position, whereby connec tion is completed between thecalling and called lines.

The side switch wiper 156, when in third position, extends the guarding potential 7 from ground G through the private wiper 87 to the connector private bank contacts of the called line, and also provides an energi-zing circuit for the cut-off winding 157 of the line switch C. Thewinding 157, upon energizing, attracts the armature 158, which operates to disconnect the line relay 159 and the jack J from the called line. When the side switch wiper 150 of the connector reaches third osition, the energizing cirouit is 'establis ed for the ringer relay 164. This circuit extends from ground G through the interrupter 165, springs 171 and 170, relay'164 and the side switch wiper 150 to the battery lead 100. Since this circuit includes the interrupter 165, the relay 161 is energized only intermittently, Each time the relay l64'is energized itoperates to disconnect the calling line; from the called line and tobridge the generator M across the called-line soas-to ring the bell 175. When the called subscriber removes his receiver, oras soon' thereafter as the relay 164 deenergizes,if, it. happens tobe energized at the time, the'called substation is provided with talking. battery'current from the central office. The circuit over 1 which this talking current flows extends from ground G 1 through the: side switch wiper 156, lower ywinding of the --relay 177, ringer relay springs 188 and-189, side switchwiper 187,

shaft-wiper "88, linef16l,'- springs 186 and wiper 179, ringerfrelay springs 18121191180 flIld'tliQ'llPPQP wind-ingiof therelay 177 to *the battery lead: 100. The'connector-backbridge relaybl77 is energized by this talking called subscriber a fter he has answered.

vrafter the conversation is" completed the frelease of' the central 'oflice apparatus is initiated by the hanging up ofthe'rec'eiver at .-the;callingsubstation. When the receiver 25 is'restored to the switch hook 26, the

springs 95 and -96 are separated, thereby breaking the energizing-circuit through the lconnector'line relay 92'. Therelay 92, upon 1 deenergizing, breaks the-"holding circuits of the release relays 139,128 and 82 of the switches F and, E, respectively, whereby they-are released in the well-known manner.-

The relay 82 of the selector E, upon deenergizing, also destroys the circuit of the .185], impulse springs,1'82,,-receiver 1.84, trans mitter 183, line160, shaft lwiper 86, side switch ing the impulse springs 31 and 32 inlthey holding winding 9 of the line switch C, whereby the plunger arm. 5 is permitted to restore to normal position to disconnect the line from the first selector E, and the cut-off armature (3 is permitted to restore to normal position to again connect the line relay 10 and the central oiiice transmitting circuit with the line of the substation A.

In the above description it will be seen that the transmitting circuit comprising the induction coil 11 and the transmitter 15 (Fig. 1) and the jack J (Fig. 3), by means of which a similar transmitting circuit may be connected with the subscribers line, is disconnected from the subscribers line, either when the subscriber removes his receiver from the switch hook to initiate a call, or when a connector switch H completes connection with the called line. Thus it will be seen that when a subscriber wishes to call another subscriber in the ordinary way, no sounds are transmitted to the con nected subscribers from the special transmitting circuit at the central office. If. however, a subscriber wishes to receive the message that is being transmitted from the special transmitting circuit at the central oiiice, he simply operates the key K to bridge the special receiver 2 across the line. Since this receiver is bridged across the line through the condensers, it does not form a conductive path for direct current, and therefore does not energize the line relay 10 to operate the line switch C; and since the induction coil 11 is connected with the line as long as the line switch C is not operated or its winding 9 energized, the subscriber may, through the medium of the special re ceiver2, hear the message which is being transmitted through the transmitter 15 and the induction coil 11. It will be seen that while any subscriber is receiving the in formation from this special transmitting circuit, his line is not prevented from being called by some other subscriber, and that in case his line is called this special transmitting circuit will be disconnected from the line by the energization of the cut-ofi 'winding'of the line. switch C of the called line as soon as the connector switch com.- pletes connection therewith.

In Fig. 6 there is shown a manual telephone substation comprising the usual receiver 201, transmitter 202, ringer 203 and condenser 204. At-the central ofiice there are allotted to the lines of this manual substation the usual answering jack J one or more multiple jacks J, line "lamp 205, line relay 206 and cut-ofi relay 207. At the substation there is provided a receiver 210 similar to the receiver 2 (Fig. 1) which may be manually connected withithe line through the medium of the key K. At the,central ofiice there is shown a special transmitting circuit comprising an induction coil 211 and transmitter 212, which circuit is normally connected with the line in multiple with the line relay in the same manner as described in connection with the automatic substation. in F ig. 1. In this instance the subscriber may hear the sounds which are being transmitted by this special transmitting circuit by simply operating the key K to connect the receiver 210 with the line in the same manner as explained in'connection with Fig. 1. YJhen the subscriber wishes to call some other subscriber, or is called, the induction coil 211 is disconnected from the line by the energization of the cut-off relay 207 whenever a plug of the operators cord circuit is inserted into a acl: of the line.

It may often be more convenient to connect the special central oflice transmitting circuit to the line at some other point than at the line switch in an automatic system, or at the regular cut-off relay in a manual system, as has been hereinbefore described. For instance, it may be more desirable to connect this transmitting circuit to the line at the distributing frame. This circuit may be connected to the line at any point desired by the use of a special relay, such as shown in Fig. at. In this figure the conductors 214: and 215 represent a portion of the line circuit between the substation and its terminus at the central oflice. The conductors 216 and 217 are assumed to lead to the transmitting circuit at the central office. These conductors are connected to the line circuit through the normally closed contact of a relay 218. The relay 218 should be connected in multiple with the cut-0H relay of the linethat is, the conductor 219 should be connected with the conductor corresponding to the conductor 220 in Fig. 1, or the conductor 221 in Fig. 6. The battery terminal of the relay should, of course, be connected with the same terminal of the battery to which the cut-ofii relay of the line switch with which it is associated is connected.

In all thecircuits hereinbefore described the central oiiice transmitting circuit and the special receiver at the substation are bridged across the line. In 5 there is represented. diagrammatically circuit arrangements whereby this apparatus is operated over av circuit, one side of which includes thetwo sides of the telephone line in parallel, while the other side of the circuit is formed through the ground or a common returnthat is, the transmitting circuitand receiver are included in ground taps which are taken off from a point between two condensers which are bridged across the line.

It will thus be seen that l have provided a very convenient and efficient circuit arrangement whereby the subscribers of an automatic or a manual exchange can be supplied with music or with news or any other desired information. While it have illustrated in Fig. 1 merely a transmitter for supplying the desired information, it is obvious that the information or music could be supplied from a record and, furthermore, that the vibrations received from such 'record could be amplified to a sufficient degree so that a single record andmaster transmitter operated thereby could be employed for supplying a large number of subscribers.

Various other modifications will readily suggest themselves to those skilled in the art and come Within the scope of my invention.

\Vhat I claim as my invention is 1. In a telephone system, a subscribers line, a special service telephone set normally connected with said line, and means for extending connection from said line to a second subscribers line and for automatically disconnecting said special service set from the line, the said means comprising a magnet for performing said automatic disconnection.

2. In a telephone system, a subscribers line, a telephone receiver adapted to be bridged across said line, a special service set normally bridged across said line at. the central station, and means for automatically disconnecting said set from the line, the said means comprising a magnet for performing said automatic disconnection.

3. In a telephone system, a subscribers line, a substation set located thereon, a special service telephone receiver at said subtation, means for bridging said receiver across said line, a special service transmitter normally bridged across said line at the central station, and means for disconnecting said special service set from the line When operation of said switch for disconnecting said ,set from the line.

5. In a telephone system, a subscribers.

line, a special service set normally bridged across said line, and automatic means for disconnecting said set from the line when connection is made With said line, the said means comprising a magnet for performing said automatic disconnection.

6. In atelephone system, a subscribers" line, means for extending connection from said line, a telephone-receiver, means for bridging said receiver across the line Without operating said, first mentioned connecting means, a special service set normally bridged across said line at the central station, and means'for automatically discon- 'necting said set from said line.

7. In a telephone system, a subscribers line, a substation set thereon including a receiver, means for bridging said receiver.

means for bridging said special receiver across said line in series with a condenser, a special service set normally bridged across said line at the central station, and means for automatically disconnecting said service set from said line, the said means comprising a magnet for performing said automatic disconnection.

8. In a telephone system, a subscribers line, a substation set thereon including a receiver, means for bridgingsaid receiver across said line, a special telephone receiver, means for bridging. said speciarreceiver across said line in series with a condenser, a special service set normally bridged across said line at the central station, means for extending connection from said line, and means for automatically disconnecting said special service set from the line When said connection is extended therefrom, the said means comprising a magnet for performing said automatic disconnection.

9. In a telephone system, a subscribers line, a substation set thereon including a receiver, means for bridging said receiver across said line, a special telephone receiver, means for bridging said special receiver across said line in series with a condenser, a special service set normally bridged across said line at the central station, andmeans for automatically disconnecting said service set from said line, the said means comprising a magnet for performing said automatic disconnection. r

10. In atelephone system, a subscribers line, a substation set thereonl including a I receiver, means for brldging sald receiverspecial service set from the line Whensaid' connection is extended therefrom, the. said means comprising a magnetifor performing said automatic disconnection.

'11. In a telephone system, a subsoribers line, a substationset' thereon including a telephone receiver, means for extending "connection from said line, said'jmeans controlled by the switohhookto extend the connection upon removal of the receiver, a second telephone receiver,fmeans for bridging said sec- .ond recelver across saidkllne Without operating said means, an'd 'a' special service set bridged acrosssaid line atthe central station. 1

1.2. In a telephone system, a subscribers line, a. substation set thereonincluding a telephone receiver, means for extending connection from said line, sa d meafis'controlled by the switch hook to extend the connection upon removal of the receiver, a second telephone receiver, means for bridging said second receiver across said line without operat ing said means, a special service set bridged across said line at the central station, and means for automatically disconnecting said special service set from the line when connection is extended therefrom.

13. In a telephone system, a subscribers line, a telephone receiver, means for brit 5;- ing said receiver across said line, a special service normally bridged across said line at the central station, a cut-off relay associated with said line, and means controlled by the operation of said cut-oil relay for disconnecting said set from the line ll. In a telephone system, a subscrilier s line, a substation set thereon, a trunk-selectswitch for extending connection from said line, means for operating sail switch upon the removal of the receiver from the hook the substation, a loud speaking telephone receiver associated with said line and means for bridgi said loud speaking re ceiver across said line with operation of said trunk-st. a special service set bridget. at the central station.

15. In a telephone system, a suhscriher s line, a substation set thereon, a trunk-selecting switch for extending connection from said line, means for operating said switch. upon the removal of the receiver from the 1g switch ind across said line phone receiver associated with said li a an means for bridging said loud spez. ceiver across said line without ca operation of said Lillllli'SElGChlllQi, swit special service set bridged across saio. at the central. station, and means for a maticall y disconnecting om the lir when line, a substation set thereon, a trunk-selecting switch for extending connection from said line, means for operating said switch upon the removal of the receiver from the hook at the substation, a loud speaking telephone receiver associated with said line and means for bridging said loud speaking receiver across said line without causing the operation of said trunk-selecting switch, a special service set bridged across said line at the central station, a cut-off relay associated with said trunk-selecting switch, and means controlled by the operation of said cut-oft relay for disconnecting said special service set from the line.

11'. In a telephone system, a subscribers line, a trunk-selecting switch for extending connection from said line, a telephone receiver, means for bridging said receiver across said line to cause the operation of said switch, a second. receiver, means for bridging said second receiver across said line in series with a condenser to thereby prevent operation of said switch, and a specialv service set bridged across said line at the central stat-lon a telephone system, a suhscribefis line, a trunk-selecting switch for extending connection from said line, a telephone ceiver, .n' ans for bridging said receiver across line to cause the operation of said switch, a second receiver, means for hridping said second receiver across said line in series with a condenserto thereby :revent operation of said switch, a special 11065 bridged across said line at the 'al station, and means for automatiby me at Chicago, Cook county, I I, this 8th day of May, 1912.

TALBOT G. MARTIN.

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