US357540A - Local battery-circuit for multiple-switch-board systems - Google Patents

Description

(No Model.) 2 Sheets-Shet'I.

J. A. SEELY.

LOGALB-ATTERY CIRCUIT FOR MULTIPLE SWITCH BOARD SYSTEMS. No. 357,540. Patented Feb. 8, 1887 III o in. I I

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J. A. CEELY. LOCAL BATTERY CIRCUIT FOR MULTIPLE SWITCH BOARD SYSTEMS. N0.'357,540.- .Pafnented Feb. 8, 1887..

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UNITED STATES PATENT Fries.

JOHN A. SEELY, OF NEW YORK, N. Y., ASSIGNOR 'IO THE WESTERN ELEG- TRIO COMPANY, OF CHICAGO, ILLINOIS.

ILOCAL'BATTYERY-CIRCUIT FOR MULTlPtE-SWlTCH-BOARD SYSTEMS.

SPECIFICATION forming part of Letters Patent No. 357,540, dated February 8, 1887.

Application filed November 15, 1886. Serial No. 218,950. (No model.)

To aZZ whom it may concern.-

Be it known that 1, JOHN A. SEELY, acitizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Local Battery-Circuits for lifultiple-Switch-Board Systems, (Case 5.) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to multipleswitchboard systems of a telephoneexchange in which metallic circuits are'employed.

The object of my invention is to provide circuits whereby the local batteries at the different subscribers stations may be utilized as test-batteries when the subscribers telephones are not in use.

My invention will be readily understood by reference to the accompanying drawings, in which-- Figurel is a drawing showing two metallic circuits connected with their switches, respectively, on two multiple switch-boards and the operators telephone and switching apparatus at the different boards. Fig. 2 is a diagram illustrative of the circuits of a line at a subsoribersstation. Fig. 3 is a sectional view of one of the loop-plugs and the connections of the two strands of the flexible cord with the point and insulated sleeve upoh the shank thereof.

In the different figures like parts are indicated by the same letters of reference.

The connections at the central office and the apparatus may be the same as heretofore used, except that the test-battery is omitted from the circuits of the telephones at the different boards. Thus the circuit of line a may be traced through the spring-jack of each of the boards and through an annunciator to ground. The branch b,or other side of the metallic circuit, is connected with the insulated frame of said switches and is normally open. The loopplugs and double-stranded cords are provided for connecting the differentlines together.

Referring to Fig. 2, it will be seen that branch a is shown connected with the bell and generator to contact'point c of the subscribers switch. The switch-lever,when the telephone is in place, is closed against said contactpoint through the local battery 6.

c and against ground-contact point d. The subscribers bell and generator are thus included in the circuit of the branch a when the telephone is hung up.

Branch 1) of the telephoneline is shown permanently connected with the switch -lever mally open at the central office, the battery 6 will not run down. Line or wire b may thus be traced normally from the insulated frames of its switches upon the switchboards to the subscribers station,and thence through a battery, e, and the switch-lever to ground through contact d, as shown.

Wire a may be traced from ground at the central office through an individual annunciator,a springjack switch on each of the switchboards, and thence to the subscribers station, thence through the bell and generator to the switch-lever, and thence to ground. T

The subscriber, by means of his generator, throws down the individual annunciator at the central office in the usual manner to notify the operator of the call. The operator thereupon makes the necessary connection with a springjack of the line by inserting a plug in the spring-jack, as shown at the first board, Fig. 1. As the subscriber removes his telephone from the switch-lever the switch is separated from ground-contact d and the contact-point c of the'branch of the wire a containing the bell and generator, and closes upon contact-point f of the local circuit and contact-point g of the branch of the line a containing the telephone and induction coil. Battery eis thus shortcircuited by the local or transmitter circuit, and the wiresab are united together at the subscribers station in metallic circuit. This metallic circuit may be traced by line a through the telephone to point 9, and thence through the battery 6 to wire I). The battery e being short-circuited, as before described, will not send any appreciable current over the subscribers metallic circuit a b. The battery 6 is thus used as a local battery when the telephone is removed from the switch, and when the telephone is upon the switch this battery is included in the open branch wire I).

Referring now to Fig. 1, it will be seen that wire b is permanently connected with the insulated frames of the switches of the line on the -different boards. By closing a ground- As wire b is nor- IOO circuit at any switch-board to the frame or test-piece of the switch of any line it may be determined whether or not the subscribers telephone is hung upon the switch-lever. If hung upon the switch-lever, the local battery 6 will be included in the branch I) of the line which is being tested, and current will thus be sent through the operators telephone. If, however, the telephone is removed from the subscribers switch, the operator will get no current when he tests at one of the insulated plates or frames of the switch of the line. Thus if he hears a click in his telephone when he makes the test he will know that the line is free, and if he hears no click he will infer that the line is busy.

Having thus described myinvention, I claim as new and desire to secure by Letters Patent- 1. In a metallic circuit multiple-switchboard system, a telephone-line one branch of which is connected through a switch on each of the switch boards and annunciator to ground, and at the subscribeflsstation through a bell and generator to the telephone-switch and to ground, the other branch of said line being connected with the insulated frames of said switches and thence to the subscribers station and through a battery to the telephone switch and to ground, in combination with switching apparatus at the subscribers station, whereby said battery may be included in a local circuit and said branches to and I) united in metallic circuit, substantially as shown and described.

2. In a telephone-exchange system, a wire, I), connected with an insulated frame or testpiece on each of two or more switch-boards and extending to a subscribers station through a battery, e, and the telephone switch to ground, in combination with a telephone included in a normally-open ground-circuit at the subscribers station, whereby on closing said circuit current will be sent from the battery through said telephone to indicate the position of the switch-lever at the subscribers station.

3. In a telephone-exchange system, a metallic circuit consisting of two branches, one of said branches, a, being normally connected from ground at the central office through an annunciator and switch on each of two or more multiple switch-boards, said branch extending to the subscribers station and being connected at the subscribers station with a bell and generator and a telephone, the other branch, b, of said line being connected normally at the central office with the insulated test plates or frames of said switches and extending to the subscribers station, and through a battery, 0, to the telephone-switch lever, in combination with a ground-connection from said subscribers switch-lever and the local circuit of the transmitter and switching apparatus, substantially as described.

In witness whereof I hereunto subscribe my name this 6th day of November, A. D. 1886.

JOHN A. SEELY.

Vitnesses:

H. B. THAYER, A. L. SALT.

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