US1313570A - Substation telephone-circuits. - Google Patents

Description

B. o. wuus. SUBSTATION TELEPHONE CIRCUITS.

APPLICATION FILED AUG.23.I9-H1.

Patented Aug. 19, 1919.

M (a @QM bzwm UNITED STATES PATENT OFFICE.

BERNARD D. WILLIS, OF CHICAGO, ILLINOIS, ASSIGNOB TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SUBSTATION TELEPHONE-CIRCUITS,

Specification of Letters Patent.

PatentedAug. 19 1919.

T 0 all whom it may concern:

Be it known that I, Bnnnann D. Wrens, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Substation Telephone-Circuits, of which the following is a specification.

My invention relates in general to substation telephone circuits but is more particularly concerned with substation circuits for automatic telephone systems.

Briefly stated, the object of is to provide a circuit'arran ment whereby there is introduced in a well own common battery substation circuit a subscribers impulse sender, also old in the art, with a view to producing a more simple and ellicient substation arranghement for automatic telephone systems than as hitherto been available.

The preferred form of the invention has been illustrated in the drawing by means of my invention two figures, of which Figure -1 is a detailed wirin diagram of an embodiment of the telephone invention whicli comprises a desk set, while Fig. is a diagrammatic showing of the fundamental principles involved.

Referrin now to Fig. 2, the talking circuit is simi ar to the arrangement shown in the patent to Scribner, #669,710, the transmitter T and a winding 4 of the induction coil I being in a bridge of the line conductors 2 and 3, while the receiver R in series with the condenser C and the other winding 5 of the induction coil I is connected in shunt of the transmitter. The above circuits of the transmitter and receiver are normally open and are closed when the receiver is removed from the receiver hook H. An inspection of the F1 ures will show that the transmitter bridge includes the switch hook controlled contact springs 6 and 1, while the receiver circuit includes the switch hook controlled contact springs 8 and 9.

A signaling bridge, comprising the ringer M and the previously mcntione condenser F, is provided as usual. It will be observed that this bridge is not under the control of the switch hook.

The subscriber-s impulse sender or callin device, indicated by reference character may be of the type shown in the patent to Blessing #1,ll9,394. It comprises essentially a pair of impulse sprin s 14 and 1."), controlled by a cam (not shown through the medium of a finger hole dial (also not shown), and a air of shunt springs 12 and 13- whic are closed whenever the dial is turned from its normal position. The impulse sprin- 14 and 15 are included in series with the line conductor 3 and their function is to produce momentary interruptions of the line circuit for the purpose of operatin the central oflice switchin devices. e shunt springs S, when c osed, short-circuit the signaling and talking circuit bridges in order to reduce the impedance and resistance of the line circuit, to prevent the interruptions being heard in the receiver, and to prevent tagvping of the bell during the transmission 0 impulses. It is to be noted that the connections of these shunt springs are such that if the calling device dial is o erated when the receiver is on the hook the ine will not be short-circuited.

In Fig. 1, aspecific form of the circuit shown in Fig. 2 has been drawn in detail. The apparatus at the right of the drawing and comprising the transmitter T, the receiver R, the switch hook H, and the calling device S constitutes a desk set telephone; w ile the apparatus at the left of the drawing and com risi the ringer M the condenser C an the induction coil l is sepa' rate from the said telephone and may mounted in the usual bell box. The telehone is provided with a terminal strip P in the base thereof and the bell box is pro vided with a terminal strip P. The various circuits are completedby means of a live conductor cord which connects the two terminal strips.

The advantageous arrangement of the various parts just described would not be possible without adding additional cord conductors and other complications were it not for the new combination of circuits.

The operation of a substation instrument embodying my new circuits is as follows: \Vhen the receiver is removed to initiate a call the switch hook controlled contact springs 6 and 8 come into engagement, respectivelv, with the contact springs 7 and 9, whereby the transmitter bridge and the receiver circuit are closed. Responsive t0 the closure of the transmitter bridge current is supplied to the transmitter rom a bridged battery at the central oilice (not shown) over the following path. Line conductor '2, winding 4 of the induction coil best I, transmitter T, switch hook springs 6 and 7, and calling device impulse sprin s 14 and 15 to line conductor 3. The bri ge at the central oflice which includes the battery may also, in accordance with the usual practice, include the controlling relay of an automatic switch, the circuit of such relay including, therefore, the transmitter brid e at the substation. It follows that the cafiing subscriber may by suitably manipulating his calling device dial produce a series of interruptions in the circuit of the controlling relay to bring about the operation of the said switch. It is important to note in this connection that as soon as the dial is turned from its normal position the substation loop is completed over a new path as follows: Line conductor '2, shunt s rin 12 and 13, switch hook springs 6 and and impulse springs 14 and 15 to line conductor 3. B the closure of the above circuit the signs ing and talking circuit bridges are short-circuited for the purposes previously mentioned. Successive operations of the dial will now result in the operation of Suecessive switches at the.exchange, until the connection is finall completed to the line of the called subscriber, it bein understood that all the switches are rovi ed with controlling relay bridges w ich with the exception of the bridge in the last switch, are successively cut ofi from the line when their associated switches are operated.

The connection *being completed, conversation may be held as desired. Since the operation of the talking circuits is well known it is not thou ht to be necessary to devote any space to t e description of such operation herei It may be mentioned however, that the ringer M which is bridged across the line during conversation, should be of very high impedance. When the receiver is replaced at the termination of the conversation the switch hook controlled contact springs are separated to remove the transmitter from the line and to open the receiver circuit. It is necessary to open the circuit of the receiver in addition to that of the transmitter for otherwise the receiver together with the two windings of the induction coil would form a shunt around the ringer M. The direct current 100 at the substation being broken by the rep acement of the receiver, current ceases to flow over the line conductors and the switches at the central otlice are according] restored to normal in the usual and we] known manner. The substation is now in condition to receive signaling currents which may come in over the line conductors and traverse the ringer M and the condenser C, whereby the ringer is actuated to advise the subscriber of an incoming call.

It will be seen from the foregoing that L have devised new and simple circuits whereby a common battery substation talking apparatus and a subscribers impulse sender are combined without detracting from the talking qualities of the apparatus and without interfering with the eilicient operation of the impulse sender, thereby producing a highly desirable substation equipment for automatic telephone systems.

Having described my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the ap nded claims.

What claim as my invention is:

1. In a substation telephone set, a line circuit, a bridge of said line includin a transmitter, a second brid e of said fine includin a receiver, a third bridge of said line inc uding a condenser, said first and second brid s normally open, means controlled by t e switch hook for closing said normally open bridges, a calling device comprising a air of impulse springs in series with one me conductor, and a single pair of shunt springseflective only when the receiver is removed to short-circuit all of said bridges upon the operation of said callinlg device.

2. n a substation telephone set, a line circuit, bridges of said line including, respectively, a transmitter, a receiver, and a signaling device, switch hook controlled means for closing the first of said bridges, a sub'scribers impulse transmitter for sending current impulses over the line circuit, a single pair of shunt springs in said impulse transmitter closed when the same is 0 rated, and circuit connections such that i the receiver is oil the hook the closure of sa d shunt frrings is efl'ective to shortc 1rcu1t the sa i transmitter, receiver, and signaling device, and such that if the recelver is on the hook, the closure of said shunt springs is effective to short-circuit said transmitter only.

t3. In a substation telephone set, a line circult; a transmitter and one winding ofan induction coil in a bridge of said line, said bridge including contact springs for closing the same a shunt circuit or said transmitter including a condenser, a second winding of said induction coil, and a receiver; a set of contact springs in the shunt circuit between the receiver and the said second coil wind-ing; a subscribers impulse sender for transmittin current impulses over the line circuit; an a single pair of shunt springs ada ted to short-circuit the transmitter bri ge when the said sender is operated.

fl. In a substation tele hone set, a line circu 1t, a ringer and a cond iinser in a bridge of said line, a transmitter and a winding of an induction coil in a second bridge of said line, a receiver and a second winding of said induction coil connected in series to form a conducting path extending from the junction of the ringer and condenser to the junction of the transmitter and said first winding, a normally open connection in the trans lnitter bridge, a second normally open connection in said conducting path, means for closing said connections, a subscribers impulse sender including make and break contacts for transmitting current impulses over the line circuit, and a single air of shunt springs in said sender adaptet to short-circuit the transmitter bridge when the said sender is operated.

5. In a substation telephone set, a line circuit, a transmitter in bridge of said line, a condenser, a winding of an induction coil, and a receiver in a second bridge of said line, a conductor common to said bridges and including a second winding of said induction coil, a normally open connection in each bridge outside of the common conductor, means for closing said connections, a subscribers impulse sender, and a single pair of shunt springs in said sender so connected that upon the operation of said sender both the transmitter and receiver are shunted if the receiver is oft the hook and the transmitter only if the receiveris on the hook.

6.111 a substation telephone set, a line circuit, a transmitter in bridge of said line, a condenser, a winding of an induction coil, and a receiver in a second bridge of said line, a conductor common to said bridges and including a second winding of said induction coil, a normally open connection in each bridge outside of the common conductor, means for closing said connections, a subscribcrs impulse sender, a single pair of shunt springs in said sender so connected that upon the operation of said sender both the transmitter and receiver are shunted if the receiver is 011' the hook and the transmitter only if the receiver is on the hook, a ter minal strip providing for the line connections and all connections of said condenser and induction coil, a second terminal strip providing for all connections of the remaining apparatus, and a five conductor cord jolning said terminal strips over which all necessary circuits are completed as set forth.

7. In a substation telephone set, a line circuit, a t 'ansmitter and one winding of an in duct-ion coil in a bridge of said line. said bridge including contact springs for closing the same, a shunt circuit for said traiismitter including a condenser, a second winding of said induction coil, and a receiver; and a set of contact springs in the shunt circuit between the recelver and the said second coil winding, a calling device comprising a pair of impulse springs in series with one line conductor and a single pair of shunt springs effective only when the receiver is removed to short circuit all of said bridges upon the ope 'ation of said calling device.

8. In a telephone substation, a line circuit including a transmitter and one winding of an induction coil in bridge thereof. contacts for closing said bridge across the line, a shunt circuit for said transmitter including the second winding of said induction coil. a second set of contacts for closing said shunt circuit and a receiver and condenser included in said shunt circuit on opposite sides of the said second set of contacts, a calling device comprising a pair of impulse springs in series with one line conductor, and a single. pair of shunt springs effective only when the receiver is removed to short circuit all of said bridges upon the operation ofsaid calling device.

Signed by me at Chicago, Cook county, State of Illinois, this 9th day of August,

BERNARD I). \VILLFL

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