US922206A - Composite signaling system. - Google Patents

Description

H. B. STONE. COMPOSITE SIGNALING SYSTEM. .APPLIOATION FILED JULY 20,1908.

Patented May 18, 1909.

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H. B. STONE. COMPOSITE SIGNALING SYSTEM.

APPLICATION FILED JULY 20,1908.

922,206. v Patented May 18, 1909.

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HENRY B. STONE, OF PROVIDENCE, RHODE ISLAND.

COMPOSITE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented May 18, 1909.

Application filed July 20, 1908. Serial No. 444,324.

grammatic form various arrangements of i used for simultaneous telegraphic and telephonic communication.

In composite-signaling systems it is customary to connect one or more tele raph branches to the'main line through the interposition of impedance coils whereby the rapidly varying telephone currents are prevented from affecting the telegraph apparatus, and to connect the telephone branch with the line circuit through the interposition of condensers whereby the more slowly varying telegraph currents are prevented from afieoting the telephone system.

It has been found however that the effi-- ciency of the telephone system is greatly diminished by the-necessity of passing the signaling or ringing currents through the I condensers which connect the telephone branch with the line circuit.

It has been proposed to remedy this defect by employing high-frequency ringing currents such as those produced by means of vibratorsbut the use of such high-frequency ringing cur- .rent is objectionable and has developed a number of difficulties and limitations inpractice.

It is the object of the present invention to provide a composite signaling system wherem the ordinary low-frequency ringing current may be employed by impressing the same on the line c rcuit on the'line side of the aforesaid condensers, if the latter be .retained, and. it contemplates in one of its aspects the eliminationof the condensers or inductostatic connection of the telephone branch, of the line circuit.

A further object of my invention is to connect the telegraph branch or branches of a composite system to the line circuit at a point or-points the potential of whichisnot affected by the developmentof the telephone signaling current so that such current will'notaiiect theztelegraph apparatus.

illherdrawings Whichaccompany and form;

a part of this application represent in dialine circuit.

circuits and apparatus whereby the fore going objects may be accomplished.

In the drawings, Figure 1 is an explanatory diagram illustrating a Well known composite system in common use today. Fig. 2 represents one embodiment of my invention in which a simple repeating 0011, having its primary bridged across the telephone side of the composite set is employed for associating the telephone branch with the Fig. 3 represents an extension of the principle shown in Fig. 2, in .Which the repeating coil has two sets of secondaries each set consisting oi two coils-connected in series with one side of the line circuit. Fig. 4 shows a modification in which the repeat ing coil has two primary windings connected in series with the telephone branch and the line circuit. Fig. 5 represents a further modification in which the rimaries of the re eating coil are connected in series with the to ephone andafe inductively related to the line circuit, the condensers on. the drop side having been discarded.

In the fi ures O 0, represent the sides of an all-meta lic linecircuit.

T T, represent the telegraph branches of the composite signaling system, said sets ineluding, respectively, the batteries B B,, the keys K K, and the relaysR R,. The tolegraph branches are connected to the line circuit at the points 0 0 respectively, and each is earthed at E. The impedance coils L I}, are

interposed between the telegraph branches and-the line circuit, and the usual shunts in cluding the condensers (l C, and the impedances L L, may be connected to earth as shown.

It is usual to connect the two pairs of condensers C (Wand C, U, in the two sides of the line circuit between the points of connection therewith of the telegraph branch and the telephone branch. Inasmuch as the ringing current .must pass through the condensers C 0- and C, C,-, which are usually condensers of from two to four microfarads capacity, and as a certain portion of said current necessarily passes through the shunts including the coils L- L,, which are coils of relatively low impedance, it will be clear that the arrangement shown in 1 isquite inefiicient for transmittinglow-frequency ring in currents. The attem t to improve the e ciencyofithe system .s own in :Fig. 1 by the use of'relatively high-frequency ringing currents has not proven successful, artly because of the disturbances induce .by such currents in neighboring lines, and partly because ofthe complexity of the a paratus requiredfor their production and t e difficulty experienced in maintaining the same in proper adjustment.

' The simplest form of my invention is shown in Fig. 2, in which as well as in the remaining figures, the reference characters have the same significanceas in Fig. 1. In Fig. 2, I represents the primary winding of a re-" peating coil, said primary being bridged across the telephone branch of the composite system between the points 1) p, and, as shown, connected in series with the springjack S ,of a telephone switch-board. I 1,, are the secondaries of said-repeating coil and each is connected in series with one of the sides of the line circuit 0 0 The ringing current from the telephone branch will be transmitted to line partly through the condensers C C C C, but principally by way of the .repeating coil which inductively translates the energy of said currents to the line to reinforce that portion of the energy of said currents received from said condensers. While the efficiency of transmission is greatly increased by the arrangement shown in Fig. 2, it has been found that variations in poten tial at the points 0 0 due to the development of the ringing currents affects the telegraphbranches and also that the telegraph current is often heard in the telephone instruments.

In Fig. 3 I have shown a systemwhereby the efficiency of transmission of the ringing current may be still further improved and atthe same time the mutual action of the tele- I graph and telephone branches greatly reduced or'entirely' eliminated. In Fig. '3 the telegraph branches T T, are connected to the line circuit atthe points 00 which are midway between the serially connected secondary windings I 1,, and I, I respectively, of the repeating coil. The primary I of said repeating coil, as before, is shunted across the drop side of the composite system between the points p p. It will be obvious that the points 0 0 in Fig. 3, which are respectively between the outer ends of the two coils of each of the two sets of secondaries of the repeating coil, are points having their potential unaflected by the development of varying current such as ringin current .in the primary of said coil, so that the telegraph instruments are not affected by said'current.

' It will be sc'cn conversely that the telegra h currents im ressed on the system at t e points 0 an 0d1v1deand lnduce approximately equal and opposite efiects in the primary I -so that the'harmful effects of such currents upon the telephone receiver will be reduced to a minimum or entirely avoided. A suitable adjustment of the condensers 0' c" and o, 0 whereby the amplitudes I and hases of the currents'fio'wing in opposite irections from the points 0 0- may be regulated, will aid in accomplishing this result. v 4 An extension of the principles shown in Fig. 3 is represented in Fig. 4, which shows an arrangement whereby the eflieiency of transmission of the ringing currents is still further increased by connecting the primaries I I, of the re eating coil in series with the In the system shown in Fig. 5 the condensers'C C, may be employed as before between the secondaries of the repeating coil and the shunts which include the impedances L L,, but the condensers O O, can be eliminated and the primaries I andI, connected -metallically in series. -'Ihese con densers being-discarded, the addition of a condenser C', as shown, between-the inner terminals of the secondaries assists in the elimination of the'effect of the telegraph currents in the telephone instruments and in-- creases the efficiency of the repeating coil..

In Fig. 5 the telegraph branches are connected at points 0 0, between which there is developed a practically zero difference of potential by the ringing currents of the telephone system, so that the operation of thetele phone system will not appreciably affect the telegraph receiver. Conversely, the currents impressed on the system bythe telegraph branches divide and induce approximately equal and opposite effects in the primary windings I, I, of the repeating coil so that the telephonereceivers will'not be injuriously affected by said currents. This may be accomplished by suitable adjustment of the condensersC and C or the coils L L or by-the adjustment of both sets of coils and condensers. It will be obvious to those skilled in the art that a simple repeating coil, or one having a plurality of secondaries, or a plurality of primaries and a plurality of secondaries, may be employed in various ways to associate the telephone branch of a composite signaling system with the line circuit, and therefore I desire it tovbe understood that although I- have described in detail several arrangements whereby the objects-of the present invention may be effected, I do not wish to limit myself to the said specific arrangements, inasmuch as they have been selected from a number of equivalent systems merely for the purpose of more fully disclosing the presentinvention.

I claim:

- 1.. In a composite signaling system, a line circuit, a telegraph branch, a telephone branch, a repeating coil having all of its secondaries connected in series with each'other nection from the to egraph branch to the line branch with said line circuit, said repeating I primary of said repeating coil across the teleand with the two sides of the linecircuit, a connection from the primary of said repeating coil to said tele hone branch, and .a concircuit through one of said secondaries.

2. In a com osite signaling system, a line circuit, two to egraph branches, a telephone branch, a repeating coil having all of its secondaries connected in series with each other and with the two sides of the linercircuit, a connection from the primary of said repeating coil to said telephone branch, and connections from the telegraph branches to the two sides of the line circuit through said secondaries respectively.

3. In a composite signaling system, a line circuit, a telegraph branch, a telephone branch, a repeating coil operatively associating said telephone branch with said line circuit, said repeating coil having a plurality of secondaries in series with each other and with the line circuit, and a connection from said telegraph branch to the :line circuit throu b one of said secondaries. I

4. n acom osite si naling system, a line circuit, two teegraph ranches, a telephone branch, a repeating coil operatively associating said telephone branch with said line circuit, said repeating coil having a plurality of secondaries in series with each other and. with the line circuit, and connections from the telegraph branches to the two sides of the line circuit through said secondaries respectively.

5. In a composite signaling system, a'li'ne circuit, a composite set including a telegraph branch and a telephone branch, are eating coil operatively associating said to ephone coil having a plurality of secondaries in series-1- with each other and with the'line circuit, a cbnnection I from said telegraph branch to the line circuit through one of said seconiilaries and connections bridging the phone side of said composite set.

6. In a composite signaling system, a line circuit, a telegraph branch, a telephone graph branch to the line circuit at a oint having its potential unaliected by the evel- 8. In a composite si naling system, a line circuit, a telegraph ranch, a telephone branch, a repeating coil having two second-' aries connected 111 series w1th each other and with one of the sides of the line circuit, 'a connection from said telegraph branch to a point between the outer ends of said secondaries, a lated to sai from said telephone branch to said primary winding.

9. In a composite si naling system, a line circuit, a telegraph ranch, a telephone primarywindi'ng inductively resecondaries, and'a connection branch, a repeating coil having two sets of secondaries each set consisting of two-coils connected in series with each other and with one of the sides of the line circuit,'a connection from saidtelegraph branch to a point between the outer ends of the twocoils of one of said sets-of secondaries, a primary winding inductively related to said secondariesand a connection from said telephone branch to said primary winding.

10. In a composite signaling system, a line circuit, two telegraph branches, a-telephone branch, a repeating coil having two sets of secondaries, each set consisting of two coils connected in series with each other and with one of the sides of the line circuit, connec- .tions from said telegraph branches to points between the outer ends of the two coils of each of said sets of secondaries, a primary winding inductively related tosaid secondaries and a connection from said telephonebranch to said primary winding.

In testimony whereof, I have hereunto subscribed HENRY B. STONE. Witnesses:

FREDERICK F. MANcnEsT -R, WILLIAM G. KENDALL.

my name this 16th day of July

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