US306669A - Signal and test circuit for telephone-exchanges - Google Patents

Description

C. H.. WILSON.

SIGNAL TTTTTTTTTTTT 1T PPPPPPPPPPPPPPP HANGBS.

.No.aog. I n Patented 0010.14, 1884*.'

.UNrrED STATES ATENT OFFICE.

CHARLES H. WILSON, OF CHICAGO, ILLINOIS.

SIGNAL ANDpTEST CIRCUIT FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming -part of Letters Patent No. 306,669, dated October 14, 1884.

Application tiled June 20, 1881. (No model.)

T0 @ZZ whom it may concern:

Be it known that I, CHARLEs H; WILSON, of Chicago, Illinois, have discovered a certain new and useful Improvement in Multiple Switch-Board Signal land Test Circuits, of which the following is a full, clear, concise, and exact description.

My improvement 'consists in connecting the testing-battery with points placed near the test-keys, so that when the key is depressed and the battery thrown to line for the purpose of testing, to see if a line wanted is in use at another board, the act of testing will call up the subscriber, provided his line is not in use.

In the drawings, Figure l is a front elevation of portions of three multiple switch-boards l, 2, and 3, showing two subscribers7 lines connected with the switches and test-keys and to ground. Figs. 2 and 3 are sections of a fullsized switch and test-key, respectively, upon lines X X and Z Z of Fig. 1.

The switch is of the usual form. lThe test# key consists of the spring a, to which the line Y of a subscriber is connected, and two contact points, b and c. The telephone-line is normally closed through contactpoints b of the test-keys of a line on the different boards to ground, as indicated in Fig. l. One pole of the local battery is connected with the contact-points c of all the test or signal keys, and signaling-instruments d are provided, as shown. The calls are sent in from the subscribers stations in any well-known way. I have shown annunciator-needles e in the tele'- phone-lines for receiving the. calls of the subscribers. I find it preferable, however, to

said. spring andthe contact-point c.

my system, when a call is sent in, the switch-l man at the board to which this call belongs at once presses against spring a of the test-keyin the line of the subscriber called for. Contact is thus broken between the spring a and contact-point b and a new contactformed between tery is thus'thrown to line, and the signalinginstrument d in the line between the contact- The bat-A point c and-the battery responds, provided the line is not in use, and by simply tapping upon the spring c the circuit of the line is closed and broken, thus calling up the subscriber.

I claim- In a' multiple switch-board system, the combination, with the calling-keys a, of the battery branching to contact-points c and the contact-points b, whereby any line may be disconnected from its normal ground and closed to said battery'upon either of the boards, substantially as specified.

` CHAS. H. WILSON. Vitnesses:

WM. S. GRANGER, GEORGE P. BARTON.

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