USRE11386E - Multiple switchboard - Google Patents

Description

V ma: M. fd

lV/if No.

M. G. KELLOGG. MULTIPLE SW1TGH'BOARD. VReissu'ed Nov; 14, 1893.`

lSlll/ ETSJ EL? 5J' @ZES UNITED t y STATES PATENT OFFICE.

MIL@ o.. KELLOGG, oE cHIoAed'ILLIN-ols.

M uLTlPLE swl'roHeoARD.

SPECIFICATION forming part of Reissued Letters Patent No. 11,386, dated November 14, 1893. Original No. 382.4717, dated May 8l 1888. Application for reissue tiled Dae'ember. 189D. Serial No. 3.73.3'73.

To all whom it may com/'erm' Be it known that I, MILO G. KELLOGG; of Chicago, Illinois, have invented certain new and Auseful Improvements inMultiple ,Switchboards for Telephone-Exchanges, of which the following is a full, clear, and exact description, reference being had to the accompany-Y ing drawings, forminga part of this Specification.

- My invention relates to a metallic circuit telephone exchange system-rnore'especially to such a system in which the lines Y are not grounded at the subscribers stations, and are' not normally grounded. at the central otticeand an organization for testing at any of the boards to determine whether a line .is in use at another board. 1

` IThe invention consists, generally'stated, in the combination with metallic circuit lines and suitable switch devices of an operators test circuit or connection and suitable test devices, by which when two lines are switched for conversation the test connection or cir- I cuit may be completed by connection with either line and the test ipstrument or device will indicate that the line is inuse, all as hereinafter described and claimed.

In the accompanying drawings, illustrating my invention: Figure 1 is a diagram illustrating the main-line apparatus and a metallic circuit that is normally .disconnected from the ground. Fig. 2'sl1ows a diagram of' the operators cord system for receiving and answering calls, switching, and clearing out subscribers lines. Fig. 3 shows an operators test system including a test plug, battery,

bell, and connections. Fig. 4 shows a moditlcation of the apparatus and system. y

In Fig. 1, A is a sectionalview of one switchboard, and A" is a sectional view ofl another switch-board to which the Isame lines are connected. I place as many boards in the oilce as are found necessary or desirable, in order to properly answer the calls and make the connections.

On each board is a spring-jack or other suitable switch for each line. Each spring-jack has a contact spring which normally bears on an insulated contact-point and has a contact-piece' insulated from the rest of the switch, (except byline connection/5,) and is adapted to receive a loop switch-plug, and when the-'plug is inserted to disconnect the spring from, the contact-l point (on whichjt normally rests) and connect tire contact-pieces of the plugwi-th the spring, 5 5 and the contact-piece, respectively. In thev ligure g, g represent the springs of the dierent switches; h, h, `the contact-points, and j, 7' thecontact-pieces. The plugs D, D, (shown in Fig. 2) when inserted into the switches, 6o operate them as above described. The contact-pieces should be so placed that a testplug or other switch-testing' device may be readily connected with them. The subscribers circuit shown in the drawings begins say, 65 at the central oilice, and passes by a wire, which we will call wire No. la, to the subscribers station, through the stationapparatus, andback to the central oftice by another wire, which we will call wire No. 1b. One 7o 0f the wiresf-saywireaNo.' lb-is connecterl 'to all the contact;pieces above ment-ionen vand their corresponding points of itsiswitches on the different boards, passing in each case to the spring tirst. I-t is then connected to wire'No. lb. If an annunciator is usedto receive the calls of the line, it is preferable to 8c place it injthe circuit of the line after it has -passed throughthe contact-points, as above,

and before itpasses from there to the contact-pieces. This line is not connected with l the ground at the subscribers stations or nor-I 8 5 mally elsewhere; but is connected with the ground at the central oftice when switched for conversation, as and for the purpose which will hereinafter appear.

Fig. 2 shows a pair of loop switch-plugs 9o with flexible loop cords adapted Vto it into the spring-j ack switches and make the switch. ing-connections for two lines which are to be connectedtogether for-conversation. One of the conductors of the cord isv grounded by a 9'5 branch wire, as shown. It is evident that when one of the-plugs is placed in the spring-jack switch of one linea-nd the other plug is placed in the spring-jack switchof another lino the two lines are connected together in metallic los circuit andthe circuit is grounded at the central cnice. X

Fig. 3 shows a test-circuit with apparatus for. use by 'an operator at any board.4 The a plug adapted to be brought into contact.

with any of the contact-pieces j, j at the board.

Each operator vshouldhave at her board av system of pairsot cords with theirplugs,with

the necessary switches, telephone, and genf erator, suitably placed and connected so as to properly conduct the business assigned'to her.

In Fig. 2 only one pairfof cords is shown.

`the contact-pieces of the plugs Others could be added to her system in ways evident to those skilled in the art. She should also have at her board a test system similar to that described above. For the test-receiving instrument she might use a telephone or other suitable apparatus in the place ot' the bell which is shown. In this gure 751,721. are

gt, n, fn the insulating material of the plugs, Y the operators switch, t the telephone, B the generator,`V theclearing out annunciator, and oc, y, y, e', z, are the vcontacts of the switch Y. a is a metallic plate on which the plugs D normally rest and with which the contactpieces of the plugs are in contact, so that when asubscriber has called and the operator has inserted one of the plugs in the switch of the calling line a circuit is 'aiorded in which the operators telephone may be included by,manipulating the switch Y. This circuit is from one contact ot the inserted plug with which one side of the line is connected to a contact of the other plug of the pair, thence by plate ct and other contact of said plug to the switch Yand remaining contact of the inserted plug with which the other side ofthe line is connected:

When an operator atany board desires to test a line tosee whether it is in useat another board, she connects her test-plug to the contact-piece j at her `board of thev line to betested, and if the liuc is in use there will he a complete circuit through her test-bell and the battery, and the bell will respond and she will know that the line is alreadyin use. In Figs. 1, 2 and 3 the circuit can be traced as follows: Beginning with the ground, thence through the test-bell and battery to the testplug, and thence through the contact-piece, and the line back to the ground (tovwhich the line is temporarily connected while switched forconversafion). Il", however, the line is not switched for use, there will be no such complete circuit when the test -is made, because the line is disconnected from the ground, and the test-bellwill not respond. Itis, however, not a necessity-in mysystem that the lines should be grounded when they are switched for conversation, if the apparatus and connections are modilied accordingly. The lines, when switched, may be connected to a common metallic test circuit or wire, to which are also connected the test-circuits at the difterent boards. In the modification shown in Fig.

i the connections are thus made. It is, how ever, convenient to use the 'ground as a part of the test-circuit and Ihave therefore herein described its use. ,Y

It is known not to be detrimental -to the workingot' a metallic-circuit telephone exchange to have the metallic circuits grounded at the central otiice while they are used for conversation, provided they are not then grounded' elsewhere, or to have the circuits joined together at one point/in each, provided they are not looped together. For these reasons my test system will not affect the successful workingof the metallic circuit system.

vThe test battery may be placed in the common ground wire or in a common testwire, to which the lines are connected when switched for conversation, instead of there being one in the test-circuit of each board after it branches from the ground or the common testwire. In Fig. `et the test-battery is shown placed in the common test-wire. Where either of the plans last suggestedis adopted, if the metallic circuit lines were normally to ground,

there would benocircuitfrom anyline through the test'battery and vtest devices to the test .plug or switch device until `the lines are switched for conversation when, as described, they will be connected with one side of the test circuit or connection'. My invention therefore comprehends atest circuit,'includ ing proper devices, that is completed on one side when the lines are switched for conversation, and is on the other side adapted to be brought into connection for testing with..

either of the switched lines.

I claim as my inventionv and desire to se, cure by-l'.etters Patentl. In a telephone-exchange system, two metallic circuit telephone-lines normally disconnected from the ground and temporarily connected together for conversation, with their circuit grounded, in combination with a test-bellgrounded on one side and connected on its other side to a switch-testing device, adapted tobe brought into connection with either line for testing, and a battery, in the test circuit -between the ground-connection on one side of the bell and the temporary ground-connection of the two lines, substanstautially as and for the purpose set forth.

2. In a telephone-exchange system, two metallic-circuit telephone-lines normallydisconnected from the ground and temporarily connected together for conversationv with their circuit grounded, in combination with a test-wire grounded on onevside and connected on its other .side to. a switch-testing device, adapted to be brought into connection with either line for testing, and a'battery and testbell in the circuit of said test-wire, substantially as and for the purpose set forth.

3. In a telephoneexchauge system, the combination of two metallic-circuit lines temporarily connected together for conversation, a test-circuit containing a test-receiving instrumeut and a test-battery, said test-circuit be- IOO instrument and battery wth'said. lines when they are thus connected for conversation, and

` l 4at the will of the operator tobe then only, a test-bolt connected to each of said metallic-circuits, and aswitchin'g device connected to said testcircuit on the other side of said instrument and battery, adapted' at the will of the operator to bebrought into electrical hconnection with either of said testb'olts, substantially asand for the purpose set forth. 1

4. In a telephone-exchange system,metallic circuit lines normally dis-connected from the ground, two or more switch boards, toeach of which the lines are connected, and switching devices at! each board adapted to temporarily connect any two of the lines together for conversation, and when they are thus connected .to ground theirV circuit, in combination with test-receiving instruments, one at `each board, grounded on one side, switchtesting devices at 'each board adapted at the will of the'operato'r to connect its test-receiving instrument on the other side to the` cir- `cuit of any line for testing, and a battery in the test-circuit thus established, substantially as and for the purpose set forth.

5. In a telephone exchange system, thecom'- bination of metallic-circuit lines, two or more switch-boards for said lines, test circuits, one` at each board, each test-circuit containing a test-receiving instrument and a test battery, Y

said test-circuits being electrically connected on one side to their test-receivinginstruments and test-batteries, and normally disconnected from said lines, switching-devices at each' board adapted to connect any two of said lines together for conversation and to connect them temporarily or when thusconnected electrically with said test-circuits on said side ot' their test receiving instruments and battery or batteries, test-bolts, one for each line on each board, each test-'bolt being connected to its line when it is switched for conversation, and switch-testing devices at each board, each connected'to the'test-circuit at its board on the other side of the testfreceiving instrument and battery, and adapted brought into electrical connection withany the purpose set forth. y

A6. In a telephone exchange system, two metallic circuit' lines each normally disconnected from one side of a test battery, in combination with switch. apparatus by which when the lines are switched togetherinto metallic circuit for conversation their circuits are connected to'such side of said battery a test plug or device connected tothe other side of said battery and 'adapted tobe broughttor testing linto connection with either line, anda test receiving instrument in the test circuit thereby established, su bs tantially as set forth.

7. In a telephone exchange system, two lnetallic circ uit lines each normallydisconnected from one side of a test circuit or connection of the test-l bolts at her board, substantially as and for which includes a test battery and'test receiving instrument, and connected with,` suchpside, of said circuit while oras longV as switched together in metallic circuit for conversation,

in combination with a test plug or device connected to the other side `ot', said test circuit or connection and adapted to be brought for testing into connection with ,either of said lines, substantially as set forth.

S. Ina telephone exchange system, thecon1` bination with two subscribers metallic circuit lines temporarily connected together in metallic circuit for conversation, of a test circuit of which the ground forms a part or connection and with one side of which said lines are then connected, the other side of said test circuit being adapted to be brought into connection with either of said lines, substantially as described.

9. In a telephone exchange multiple switch board system, metallic circuit lines, a test terminal for each line on each board adapted to form connection-with a contact of a switch plug when a plug is inserted into the line switch for switching at its board, a circuit connection for each line to which -said test terminals of the line are perman eutly connected, test battery connected on one side to said cen-l tact piece of the plug througha flexible conductor, while orA as long as the plug is in the switch, a test receivingv instrument at Aeach board connected on one side to a test plug or device adapted to be brought for testing into connection with each of said terminals at its board, and on its other side to the other side ofsaid testbattery, whenever the line is tested and is then switched and connected in closed circuitior conversation.

10.V In a telephone exchange, multiple switch boardsand telephone lines, each permanentlyconnected to al test terminal on each of said boards, in combination with test battery connected on one side to a line whenever and as long as the lline is switched and connected inl closed circuit for conversation, but disconnected on its other side from the line except when a test plug is connected to Y the line for testing and test receiving instru-V ments, one at each board, leachconneeted on one side to-theother side of said test battery whenever a line istested and is'thus switched, forconversation, and on the other sideto a test 'plug or devicev adapted to be broughtinto connection with said test -terminal at its board, substantially as set forth.

ll. In a telephone exchange, switch boards, subscribers talking circuits, test terminals on each of said boards, for each circuit, acircuit connection from each talking circuit, permanently connected with its test terminals, in combination with test battery to one side of which a circuitis connected whenever and as long as switched and connected in closedc'ircuit for conversation, but to the other side of which the circuit is not connected ex' multiple for testing and test receiving instruments,

IIO

ceptwhen a test plug is connected to the line one at each board, each connected on one side to the other side of said test battery whenever the circuit is tested and is thus switched for conversation, and on the other side to a test plug or device adapted to be brought into connection with said test terminal at its board, substantially as set forth.

12. In a telephone exchange system,v a metallic circnit-line, a switch for said line containing two contact-pieces to which the two sides or branches of the line are respectively connected, and aloop-plug, with the two conductors of its double conducting cord connected to its two contact-pieces, respectively, said plug being adapted to be inserted into said switch, and when inserted to connect its two contact-pieces with the two contacepieces of the switch, in combination with a test1e ceiving instrument' connected on one side to one of the conductors of said double cord. and on the other side to a switch-testing device adapted to be brought into connection with a contact-piece of the line, and a battery in the circuit between the switch-testing device and the contact-piece of the plug connected.l

therewith, substantially as set forth.

13. In a telephone exchange system, metallic circuit lines, multiple switchboards for' said lines, switches for said lines, -one switch on each board, each switch-containing two con tact pieces, to whichthe two sides or branches of the line are respectively connected, and pairs of loop-plugs at each board, each plug `being adapted to be inserted into any switch,

and when inserted to connect its two contactpieces with the two4 contact pieces of the switch, respectively, the two contact pieces of one plug being connected with the contactpieces of its mate, respectively, by two. conductors with exible ends, in' combination with test-receiving instruments, one at each board, each instrument being connected on one side to one o'f the conductors connecting each pair of cords and on its other side to a switch/(testing device, adapted at the WiIl of the operator to connect it to any line for testing, and a battery `in the test-circuit thus established, substantially as set forth.

14. In a telephone exchange system, two

subscribers lines connected together for conversation, their combined circuit being then o r as long as they are thus switched for conversation connected with one side of a test battery, but l.not with the other side of said battery, except when a plug is applied to the circuit for testing in combination with a test receiving instrument connected onne side to the last mentioned Side of said battery and on its other side to a test plug adapted to be brought for testing into connection with either line.

In witness whereof I vhave hereunto subscribed my name.

MIL() G. KELLOGG.

Witnesses:

A. C. OWEN, FRANCES D. KELLOGG.

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