US486507A - scribner - Google Patents

Description

(No Model.)

0. E. SGRIBN ER. TEST SYSTEM'FOR MULTIPLE SWITGHBOARDS.

No. 486,507. Pa-tented Nov. 22, 1892.

WITNESSES )Q INVENTOR WM/WWIQMQ 0h arZeSEScrihmer 4 fiw. BMWmW ATTYS UNITED STAT-ES PATENT FFICE.

- CHARLES-E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WVESTERN ELECTRIC COMPANY, OF SAME PLACE.

TEST SYSTEM FOR MULTIPLE SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 486,507, dated November 22, 1892.

Application filed February 11, 1892. Serial No. 421.174. (lilo model.)

To all whom it may concern: ater of the line. In such acase the same con- Be it known that I, CHARLES E. SORIBNER, tacts which perform the function of rendera citizen of the United States, residing at Chling the individual annunciator unresponsive cago, in the county of Cook and State of Illiwhen a connection is made to line will per- 5 nois, have invented a certain new and useful form the additional function of indicating the Improvement in Test Systems for Multiple idle or busy condition of the line when tested Switchboards, (Case No. 291,) of which the folwith the testing apparatus of my invention. lowing is a full, clear, concise, and exact de- The testing-plug may be one of the regular scription, referencebeing had to the accompaconnecting-plugs of an operators telephone 1o nying drawing, forming a part of this specioutfit. The source of telephonic current may fication. be the secondary coil of an induction-coil My invention relates to multiple-switchwhose primary is in circuit with a battery board systems for telephone-exchanges. Its and a microphone lightly adjusted and kept object is to provide means whereby it maybe in continuous slight vibration. The induced 15 certainly determined at any board whether current in the secondary of the'induction-coil a line is already in use at some other board then finds circuit through the telephone-reor not, said means being distinct and separate ceiver in parallel with it and produces a confrom the line-circuits. tinuous rustling noise therein. Thus to an Myinventioncomprisescontact-pieces upon operator testing a line the cessation of the 20 the different jacks of the line, adapted to be sound in her telephone indicates that the line crossed together by a suitable contact-piece is already in use at some other switchboard. upon the connecting-plug, corresponding con- My invention is illustrated in the accomtact-pieces upon the different jacks being conpanying drawing, wherein I have shown it in nected together, and novel means for deterconnection with a multiple-switchboard sys- 2 5 mining at any spring-jack when the said contern in which a retardatioircoil is included tact-pieces are short-circuited at some other with the individual annunciator in a branch jack. Said means consists of a testing-plug circuit between the two sides of the telephonehaving two contact-pieces which are adapted -line, the annunciator being short-circuited to make contact with the said contact-pieces when a connection is made to a line. 30 of the spring-jack, a telephone-receiver in a In the drawing two telephone sub-stations circuit between the two contact-pieces of the l and 2 are shown connected each with two testing-plug, and a source of telephonic unspring-jacks upon two sections of switchboard dulatory current in a parallel circuit with the and with individual annunciator upon one telephone. This source of telephonic unduof the boards. The two lines are shown in 5 5 latory current will then normally create a connection for communication through a continuous and preferably slight disturbcord-circuit of well-known type equipped with ance in the telephone-receiver; but the curmy testing apparatus. Asecond cord-circuit rent will be wholly shunted from the teleis shown, one of its connecting-plugs being phone when the testing-plug is inserted into placed in position for testing one of the lines. 0 40 the spring-jack of a line already in use The apparatus at the sub-station 1 is of the through the contact-pieces of thetesting-plug, ordinary character, consisting of a callingcorresponding contact-pieces of the springgenerator at and a call-bell a in a branch jack tested,and the cross connection between from one side of. line b, a telephonetransmitthe contact-pieces of the jack in which a conter a and a receiver a in another branch 5 5 necting-plug is present. from the same side of line, and a gravity- My improved testing system is especially switch 6%, connected to the other side of line adapted for use in connection with a mulb, adapted toconnect either the calling aptiple-switchboard system in which contacts paratus orthe telephone apparatus in the lineupon the spring-jacks are provided, adapted circuit, according to the position of the switch. too 50 to be short-circuited to shunt or otherwise The linesb I) extend to an exchange, where render inoperative the individual annuncithey are connected to line-springs one, re-

spectively, of the two spring-jacks d d upon two sections of multiple switchboard e 6. An individual annunciatorf of ordinary construction and a retardation-coil 9, also of wellknown character, are included in a loop joining the two sides of line I) h. The spring: jacks are provided with additional contactpieces or test-rings h, which are connected together and by a conductor to a loop including the retardation-coil and the individual annunciator at a point midway between them. The connecting-plug t is of the ordinary twopart type, having tip it, making connection with the line-spring c, and sleeve making contact with the line-spring c, which is made longer for that purpose. The extra contactpiece h also makes contactwith the sleeve 70 ofplug 2', whereby longer line-spring c and-- the piece h are crossed togetherawhenwthe plugis inserted into the spring-jack.- circuit connections are sodisposedthah the, individual annunciator f is;short-circuited, when the line-spring c and the piece h are thus crossed together. Theapparatus and disposition of the circuits of sub-station2 is similar .to that of sub-station 1, the, line b be: ing continued through earth instead of a complete metallic conductor. Its individual annunciator is placed upon another switch:- board a. Like contact-piecesof the twoplugs of a pair are connected together by conducts orsin the "usual way, calling-keysnbei-ng in.- cluded, in these conductors, each; adaptedto disconnectboth contact pieces of one. of the plugs from ,those of the otherand to connect them to wires m m,-forming the terminals of a callinggenerator 01, whereby call signals may be sent to any line. A .clearingout annunciator 0 is placed in a bridgeconnection between the differentconductors joining the;

two: plugs. A listening-keyp is provided,

adapted to connect the terminals of a tele-i phone-set-q to the differentconductors orcordstrands in the usual manner when :itsplunger is depressed. The secondary r of the induction-coil r is placed in a parallel circuit with the telephone-set q. The'iprimaryv-r of this induction-coil is included inlcircuit with a battery .9 and a microphone t, which is ad-; justedlightly and kept in continuous slight vibration.

I willnowexplaiu the operation of the sys: tem shown, giving specialattention to the operation of testing bymy invention to deter mine whether a line is alreadyin use ornot.

Suppose, for example, that subscriber at sub-station 1 wishes to communicate withsu-b scriber-at substation 2. He operateshis callinggenerator a and the switch, a being down, sends a current over the lines b 12', which erated, attracting the attention of theoperar toratthe board 6', whereon it is situated to 1311003111. v The operator then-inserts one con: meeting-plug 'i of her pair into the jack d'.'

The

A local short circuit is now closed about the individual annunciator f, which may be traced from one side of that annunciator by the branch of line b to the line-spring c of jack d, thence to the sleeve 70 of the plug '1', thence to the extra contact-piece or test-ring h of the jack, thence returning to theannunciator f. Hence any subsequent calling-current sent over the lines b Z1 will be wholly shunted from the annunciatorf, which will therefore be unresponsive. The telephonic current of lines I) b will not, however, be shunted through the coil 9 on account of its high self-induction. The operator having thus established a connection between her cord-circuit and the calling line, depresses the plunger of her'listening-key p, as is shown in the upper cord-circuit at boarde, thereby connecting her telephone set in a loop with the lines I) 1).

Having learned the connection desired, she proceeds to test the line called for. This-she does by inserting'the other connecting-plug 7; of her pair a slight distance into the jack 01 0f the line called for ather board until the tip of the plug makes--- contact with the longer line-spring of that:

jack, at the same time fixing her attention upon the faint rustling noisein hertelcphone. The plugt' at her board 6 is shown in position for making sucha test of .the jack d of lines to station 2. It now the line tested be in use,'as is actually theoasein the drawings the secondary. r of induction-coil a" will be provided with a short circuit through one spring 0 of the jack d thence to conductor 1) to theline-spring-c' of jack d to the sleeve 'kof the plug in that jack, thence to the testring Jareturuing to 'test'ring h of jack d thence to the sleeve of plug 1)? through the ICC other-side. of listening-key" p to the; other- 4 terminal of coil 9. The telephonic current from the induction-coil r is thuswholly shunted from the telephone set (1, producing complete silence therein, thus indicating to the operator testing that the line tested is al-t ready in use at some otherswitchboard. If the line tested were not in use, a circuit would still exist from the tip to the sleeve of the testplug, but would contain the coil of the elec-- tro magnet of the annunciator f of the line tested, which, being ofhigh resistance and self-induction,would not formany appreciable shunt to the telephone set, and hence would not materially reduce the noise in the tele-- phone. Thus-a complete disappearance of noiseiin thetelephone of the testing-operator is a certain indication thattheline tested is already in use. It will be noted that thistest is effected without disturbingthe condition of the, line tested andwithout at any time attachlnga ground orvcommon connection to either'the line or the toperators-outfit.

Assume that the operator atboard e finds linesto station2 not in use. She then inserts the other plug t of her pair into the jack The two sub-stations are thus looped into a continuous circuit, which may be traced from station 1 over the lines b b to the line-springs c c of jack d, thence to the corresponding contacts of plug '11, thence through the ringing keys ll to the similar contacts of the plug 2, thence to the corresponding contacts of the jack (Z and over the lines 19 b to sub-station 2. The operators telephone q is in a bridge connection between the two sides of this circuit. The operator now depresses the plunger of ringing-key Z, thus connecting the two contact-pieces of the plug 11' to the two poles m m of the calling-generatorn, thereby sendin g a calling-signal to the sub-station 2. llaving assured herself that the subscribers at station 1 and 2 are in communication, she allows the plunger of listening-key p to rise, thus disconnecting her telephone set. When the communicating subscribers have completed their conversation, one of themfor example, subscriber at station 1-may send a clearing-out or disconnection signal. This current will find circuit to the line-springs cc of jack d, thence through the cord-circuit to the clearing-out annunciator 0, which will thus be operated and will indicate the disconnection-signal to the attendant. An inconsiderable portion of the signaling-current will find circuit through the retardation-coil g; but none can by any possibility operate the individual annunciator f of either of the connected lines.

Many other circuits for multiple switchboards have been devised to which my invention is equally applicable. I do not deem it necessary to describe these systems further, since the application of my invention thereto may be readily made by any one skilled in the art. I do not limit myself to the employment of an inductioncoil r as a source of undulatory current or to the vibrating microphone 15 to induce such current. Any other source of slight telephonic current or current of rapid pulsation or alternation may be employed in connection with the operators telephone set in the manner I have described. Moreover, it is not essential that the operators telephone be employed as a responsive device. Other appliances adapted to give an audible or visual response upon the cessation of current through them may be employed in place of the telephone set q, and a source of current suitable to the particular responsive device may be employed. Many modifications of my invention may thus be constructed without departing from the spirit thereof.

Having thus described my invention and the mode of operation thereof,I claim as new and desire to secure by Letters Patent- 1. In a testing system for multiple switchboards, the combination, with a device adapted to give a suitable response upon cessation of current through it, of a source of electricity in a parallel circuit therewith and contactpieces constituting terminals of said parallel branch circuits, adapted to be applied to the contact-pieces of a spring-jack, whereby it may be determined whether the said contactpieces of the spring-jack are shortcircuited or not, substantially as described.

2. The combination,with a group of springjacks, each having two contact-pieces adapted to be crossed together by a connecting-plug placed therein, like contact-pieces of all the spring-jacks being connected together, of a testing-pl ug having two contact-pieces adapted to be applied to the two contact-pieces of a spring-jack, and a source of electric current and a responsive device adapted to give a response upon the cessation of current therethrongh in parallel circuits between the two contact-pieces of the plug, substantially as described.

3. The combination, with spring-jacks, each having two contact -pieces adapted to be crossed together when connection is made thereto, like contacts of the different springjacks being connected together, of a testingplug having contacts adapted to be applied to the contact-pieces of a spring-jack and a source of telephonic undulatory current, and a telephon e-reeeiver in parallel circuits, Whose terminals are connected to the two contactpieces of the testing-plug, respectively, substantially as described.

4:. In combination with 'a telephone-line circuit extending from a sub-station to a central station'and connected with spring-jacks at the central station, each having two linesprings and a test-ring, a connecting-plug adapted to be inserted into any spring-jack having two contact-pieces, one adapted to make contact with one of the line-springs and the other adapted to cross together the other line-spring and the test-ring of the jack, a testing-p111 g having two contact-pieces adapted to be applied to the test-ring and to that line-spring which is adapted to be crossed with the test-ring, respectively, and a source of telephonic undulatory current, and a telephone-receiver in parallel branches, whose terminals are connected to the two contactpieces of the testing-plug, respectively, substantially as described.

In witness whereof I hereunto subscribe my name this 30th day of January, A. D. 1892.

CHARLES E. SORIBNER.

Witnesses:

FRANK R. MOBERTY, GEORGE L. ORAGG.

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