US518334A - Telephone-exchange system - Google Patents

Description

(N0M0de1.)-

J. I. SABIN 85 W. HAMPTON.

TELEPHONE EXGHANGE SYSTEM.

Patented A l 17, 1894.

alz n 17206227573". 01m [,5 ZZLKLTH 0-774 UNITED STATES PATENT OFFICE.

JOHN I. SABIN AND WILLIAM HAMPTON, OF sAN FRANCISCO, CALIFORNIA.

TELEPHONE-EXCHANGE SY ST EM.

SPECIFICATION forming part of Letters Patent No. 518,334, dated April 17, 1894. Application filed April 13, 1893. Serial No. 4'70.2 9- (No model-l .To all whom it may concern.-

Be it known that we, JOHN I. SABIN and WILLIAM HAMPTON, citizens of the United States, residing in the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Systems for OperatingSubscribers Signaling and Clearing Indicators on Metallic Circuits, of which the following is a specification.

Our invention relates to telephone systems, and its object is to reduce and render more uniform the time required to secure connection and to provide means, whereby signals for disconnection and for calling maybe transmitted to the central office with minimum exertion on behalf of the subscriber.

Our invention in its preferred embodiment comprises a metallic circuit telephone line extending to a switch at the central office, or in multiple systems to the switches upon the several boards. A pair of contact anvils are provided against which the line springs normally rest, thecontact anvils being connected to a local circuit including the operators cap telephone. A switch is provided at the subscribers station, preferably operated by his telephone hook which is normally open, but which, when closed, connects the subscribers telephone set in circuit with the operators cap telephone.

It will be understood that inexchanges where a single operator cannot attend to all of the calls, each operator attends to'a definite number of the subscribers of the exchange, both according to the multiple board system and the divided board system. The contact anvils belonging to the spring jacks of all such subscribers are connected through the operators cap telephone, so that any one of the subscribers so connected may cut himself into circuit even though the operator be holding conversation with another subscriber. The operator becomes trained in attending to the various calls though several be calling for connection at the same time. The subscribers when in conversation are connected by'a pair of plugs provided with two strands, a tip and a sleeve strand. The line springs normally in contact with the contact anvils are moved away from the same when the plug is inserted, theoperators cap telephone being thereby cut out of circuit. The operators listening-in telephone, when used, and the generator are adapted to be bridged between the cord strands. Between the strands is provided a bridge connection containing a battery, and an indicator is provided therein or a pair of indicators are provided in the strands uponopposite sides of said bridge to serve as clearing-out indicators.

We will describe our invention more in detail in connection with the accompanying drawings, in which- Figure 1 illustrates two subscribers metallic circuits connected together for conversation. Fig. 2 shows a manner of connecting the operators local circuit in a multiple board system connected according to the series switch plan.

In Fig. 1 we have illustrated the subscribers line extending to a single board at the central office, it being understood that our invention may equally'be applied to multiple boards, as illustrated in Fig. 2, or by extending the lines to switches in multiple at the other boards,in which case it would be preferable to extend the operators local telephone circuit through the several spring jacks so that a connection at any board would serve to cut the indicator from circuit.

The limbs a a of the metallic circuit ofsubscriber A are connected with the line springs a a. Likewise, the limbs 19' b of the metallic circuit of subscriber B are connected with the line springs 19 17 The springs a a rest normally against contact anvils c c, which are connected with the local metallic circuit containing the operators cap telephone. Likewise the springs b 6 rest normally against contact anvils 0 0 also connected through the operators cap telephone. A switch c is provided, by means of which the operator,-when she desires to remove the cap telephone, may cut the same from the circuit, and include therein the battery e and the operators individual indicator e. When the battery and indicator are thus in circuit the subscriber, by removing his telephone from the hook, closes the battery circuit, and the indicator displays the visual signal, thus informing the operator that a connection is desired. She may then replace the cap telephone and receive the order. When in conversation the subscribers are connected by a pair of plugs and a double stranded cord. The plugs, when inserted in the spring jacks, move the line springs away from their contact anvils, thereby cutting the cap telephone out of circuit. The operators listening-in telephone set fis included in a bridge between the two strands of the cord, and a key f is provided whereby the telephone may be bridged into circuit. The calling generator g is likewise includedin abridge between the strands, a pair of keys g 9 being provided whereby the calling currents may be sent through either plu A battery It and an indicator h are included in a bridge between the two strands of the cord connector. So long as the telephone at either subscribers station remains off the hook the circuit of battery It is closed through indicator h, but so soon as both hang up their telephones, the circuit of battery it is opened and the indicator being no longer energized, indicates a desire for disconnection. In order that the circuit through said battery may be open except when the telephone is off the hook, the bridge containing the bell may contain a condenser t'. Instead of a single clearing-out indicator h, a pair of indicators 7L2 72. may be employed, as indicated in dotted lines, the indicator It being controlled by subscriber A, while indicator k is controlled by subscriber B.

It is evident that other forms of subscribers station apparatus may be employed, the requisite being that the circuit remain closed at the subscribers station while the subscriber is talking.

We will now describe briefly the several operations required to secure connection between two subscribers. Subscriber A, wishing to talk with subscriber B, removes his telephone and is immediately in circuit with the operators cap telephone. The operator having received from the subscriber the number of subscriber B, inserts plug on into the spring jack of subscriber B and bridges her listening-in telephone set between the cord strands. If B is busy through a connection at some other board, there will be a difference of potential between the line springs of the spring jack, and as the plug is inserted she will hear a click in her telephone. If subscriber B be not busy, the operator inserts plug m in the spring jack of subscriber A, and depresses ringing key 9 to send a calling current to subscriber B. Subscriber B having responded, she cuts out her telephone set and the subscribers are in connection. When the conversation is completed, the subscribers hang up their telephones, thus opening the circuits of the battery it through the indicator h, when one is used, or through indicators 71. h when two are used.

This application is one of a series of com currently pending applications Serial Nos. 464,509; 465,791; 490,950, and 499,954 and so far as anything shown herein is claimed in anyof said applications, this application is to be considered subsidiary thereto.

Having described our invention, what we claim, and desire to secure by Letters Patent, 1s-

1. The combination with a metallic circuit telephone line, extending to the central station, of a metallic local circuit containing the operators cap telephone normally in circuit with said line, and means at the subscribers station for closing his telephone set in circuit with said cap telephone, substantially as described.

2. The combination with a metallic circuit telephone line extending to the central station and normally open at the subscribers station, of a metallic local circuit containing the operators cap telephone normally in cir' cuit with said line, and a switch at the sub scribers station adapted to be actuated by the removal of the telephone from its hook to close the subscribers telephone set in circuit with said cap telephone, substantially as de' scribed.

3. The combination with two metallic circuit telephone lines extending to the central station and normally open at the subscribers station, of a local metallic circuit containing an operators cap telephone normally in circuit with the line of the calling subscriber, but cut therefrom by the act of making connection at the central station, means at the subscribers station for closing his telephone set in circuit with said cap telephone, a double stranded cord connector looping the two telephone lines together at the central station, a clearing out indicator in circuit at the central station, a battery in a bridge between the two strands of the cord connector, and means at the subscribers stations for maintaining said battery circuit open or closed to cause said clearing out indicator to display the desired signal, substantially as described.

111 testimony that we claim the foregoing we have hereunto set our hands and seals.

JOHN I. SABIN. [L. 3.]

WILLIAM HAMPTON. LL. s] Witnesses:

EDWARD E. OSBORN, (3. W. M. SMITH.

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