US1527820A - Automatic telephone system - Google Patents

Description

Feb. 24, 1925.

W. T. POWELL AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1919 ATTORNEY MMO zu m.

Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

WINERED m. POWELL, or ROCHESTER, NEW YOEE, essieNoE To THE srEoNrEEEG- CARLSON TELEPHONE MANUFACTURING COMPANY, or ROCHESTER, NEW YOEK,

A. CORPORATION 0F NEW-YORK.

.AUTOMATIC TELEPHONE S-YSJ'JEILVI,`

Application :tiled July 1, 1919. Serial No. 307,815.

To zZZ whom it may concern Be it known that I, VVINFRED T. POWELL, a citizen of the United States, residing at Rochester', in the county of Monroe and State of New York, havepinvented certain new and useful Improvements in Automatic Telephone Systems (Oase 47), of which the following is a full,clear, concise, and exact c lescription.`

This invention relates to telephone systems, and more particularly to telephone systems employing automatic switches in completing Connections between calling'and called subscribers.

In systems of this character it has formerly been the practice to directively operate an automatic switch by impulses transmitted from a distant point and then to directively select lthe ywanted line in the group previouslyv selected. This method of operation required group and line selecting mechanisms as well as change-over mechanisms, that is, means for disabling the group seletting mechanism while the line selecting` mechanism is in operation.

One of the features of this invention is the provision of means whereby an au-tomatic switch may be advanced a distance proportional to the number of impulses transmitted in several series.

Another feature of the invention is the provision of means whereby an automatic switch moves in 'the` same direction inr response to a. plurality of impulses from a distant point, the total number of steps taken by the automatic switch being equal to the sum of the impulses of the various series transmitted.;

Another feature of the invention relates to means for signaling a wanted telephone line.

An additional feature of the invention is the provision of circuits for testing a wanted line.

Fig. l of the drawings diagrammatically represents a portion of the telephone system employing the present invention, and shows a calling llineeXmllidecl through the brushes or Wipers of a numerical Switch te a called line. The portion of the drawing included within the dotted circles represcate impulse Senders which may be of any ofthe well known types that have shuntae SpringsL for shuntng the transmitter.

during the transmission of impulses. A push button is provided at each of the substations to control a break point in aV conductor other than the talking conductors that is employed for testing and signaling the wanted line. y

Fig. 2 of the drawings is a front view of the dial of the sender indicating that the sender is arranged to transmit impulses on the decimal basis in addition tO` other series of impulses, one having twelvev impulses in the series and the other twenty impulses. Fig. 3 of the drawings is va schematic showing indicating that the switch, represented by the brushes 20, 2l and 22 of Fig. l, has fifty-two terminals. This view also indicates the various adjustments of dial of Fig. 2 to set the brushes of the swit h in engagement with any ofthe desired lines. V

The switches employed in this system are of the well known rotary t-ype, preferably provided with fifty-two terminals as men-- tioned which are arranged in an arcuate bank for engagement by brushes which are progressively advanced step-by-step by a ratchet and pawl arrangement and are restored to normal by a well known release magnet. The release magnet enployed in connection with the switch may be of any type'which has a sluggish armaturel to control the. holding dog'. It should be stated that all of the terminals of the switch are connected to outgoing lines. In the present arrangement the rst terminal of the switch designated trunk in Figi 3 is connected to ank outgoing trunk to a distan-t exchange. To select this trunk it is neessary only to remove the receiver from its switchhook whereupon the switch individual to the calling line will move -to an offV normal position as will be described. The push button is then depressed to signal the distant eX- change. i i

Although a dial sending any number of impulses may be employed in connection with the present system, it is desirable in the present arrangement yto employ a sender which sends series of twelve impulses 'and twenty impulses inaddition tothe decimal `arramgement of impulsingnow in use.

W'ith this brief description of the apparatus employed, it is believed that the Vpresent inyention will best beunderstood describing the method of establishing a connection between a calling subscriber at A and a called subscriber at B. lVhen the calling subscriber at A removes his receiverl from its switchhoolr, a stepping relay SR- individual to this line is energized in a circuit extending from grounded battery, winding or' the relay SR, ring conductor l, primary winding ot the induction coil at the substation through the transmitter and impulse spring 2, tip side ot the line 3, winding of the impedance Coil d, to ground. In response to the energization of the stopping relay Slt, the motor magnet Mii/i7, is operated over a circuit completed from grounded battery, through its winding, armature and back Contact, inner front contact and armature or the stepping relay SR, contact ft', ott normal spring ON, lett hand low resistance winding ot the relay 5, to ground. The motor magnet MM is operated in this circuit and causes the numerical switch which it controls, to advance one step to an off normal position in which it remains until the calling subscriber dials a series of impulses.

ln response to t-he first series ot impulses, the stepping relay SR vibrates its armatures once for each impulse transmitted,` and the motor magnet MM is operated in synchronism with the stepping relay SR, over a circuit traceable from grounded battery, winding ot the motor magnet MM, conductor 6, lower-most bach contact and armature of the relay 7, conductor 8, right-hand bac-lr contact and armature of the stepping relay SR, contact 9 and od normal spring ON, winding of the relay 5, to ground. The motor magnet Mhil thus advances its numerical switch one step in response to each imA pulse transmitted 'from the substation at f The lower winding of the relay 7 has previously been energized over a circuit completed from grounded battery, lower winding of the relay 7, contact 9 and ott no 1mal spring, winding of relay 5. to ground. rlhe energization of only the lower winding of the relay 7' will not cause this relay to attract its armatures, but will maintain these armatures in their alternate position whenever attracted.

It will be noted that a circuit for the release magnet REL is closed in parallel with the operating circuit of the motor magnet M'M just described, but since the armature 10 of the release magnet is sluggish, it will notbe attracted during momentary energizations of the release magnet and therefore the numerical switch will not be released at this time.

In response to the next series ot' impulses, if the Wanted substation is designated by a two-digit designation, the numerical switch under consideration will continue to be advanced in the same direction stcp-bystep in 'response to the impulses from the sender at substation A, at the end ot which series the switch will have a number ot steps equal to the sum of impulses of the two series. It it is necessary to dial a third series of impulses, the numerical switch will continue to be advanced in the same direction as in the case of the preceding series ot impulses until the terminal ot' the wanted line is reached. Y

lt now becomes necessary to test the want,- ed line to determine whether or not it is engaged, and if it is notengaged, to apply signaling current to it. These operations are accomplished in the following manner. The subscriber at A after having completed the sending ot' the directive impulsesv` presses the push botton 11, and thereby closes' a circuit from grounded battery, winding of the ringing relay 12, upper winding el the electrically polarized relay 7, conductor` 13, contacts of the push button 11, contact 14 and shunting spring of the sender, contact 2 of the impulse spring, tip conductor 3 of the line, winding of the impedance coil el., to ground, and since the upper winding of the relay 7 is energized in the same direction as the lower winding, this electricallj.' polarized relay 7 attracts its armatures.

The relays 7 and 12 are energized in the circuit ust described and attract'their arinatures to apply signaling current to the wanted line. At the lower armature and front contact of the relay 12, a circuit is closed from ground, over conductor 15, back con-- tact, armature and winding ot the magnet 1G ot the ringing machine, to grounded battery. The ringing machine thereupon operates to induce an alternating current in a circuit extending from ground, lamp 17, secondary winding of the induction coil, lamp 18, conductor 1 9, uppermost' trout con-Y tact and armature ot the relays 12 and 71 brush of the numerical switch through the closed impulse contacts of the sender through the condenser and bell ot the substation at B, ring conductor ot the `allcd line, brush 21 of the numerical switch` inner-most front contacts and armatures ol relays 7 and 12, toground. The relay when energized as described vabove is maintained energized during conversation through its' lower winding.

Let it be assumed that the wanted subscriber is busy when the brushes 20, 21 and 22 ot the numerical switch were placed in engagement with the terminals of this line. Under this assumption a guarding ground will be present on the test terminal 23 of the wanted line, which is applied through the low resistance winding ot the relay 5, an ott' normal spring and contacty similar' tol 9. a conductor similar to 24 of the other numerical switch that is in engagement with the wanted line, to the test terminal 23.

Under this condition the upper winding ot lll the electrically polarized relay 7 may be energizedtrom this ground` on test terminal 23, test brush 22, inner-most lower back contact and armature and uppei windingl oit the relay '7, conductor 13, push button 1l, contact 14 and shunting spring ot the sender, the transmitter andY through switchhook contacts, primary ,winding of the induction coil at the substation'A.,windingfofthe stepping relay SR, to grounded batter-y. ln this instance the windings ot the electrically polarized relay are energized in opposite directions so that this rela-y does not att lact its armatures, and ringing current is not applied to the wantedline. The relay 12, however,v which is energized whenever the pushbutton 1l is depressed, closes` a` circuit trom ground, lower armature and front contact of relay 12. conductor 15, armature, back contact and right hand winding of relay 5. to; grounded battery. In this circuit the relay 5 rapidly vibrates its armatures-thus inducing acurrent which causes a tone in the receiver ot the calling subscriber at A in a circuit extending from ground, left hand winding of the relay 5, ott' normal spring andk contact similar to 9, conductor similar to 24 and test terminal 23 of the wanted line at the switch already in engagement withl this line,test brush 22 of the numerical switchy individual to the calline line. inner lower back con-tact and upper winding of the relay 7, conductor 13, push button 1l, contact 14C, shunting spring of the sender through the condenser and secondary winding of the induction coil at the substation, through the receiver and switchhook contacts, primary winding of the in-p duction coil, stepping relay SR, to grounded battery.

Battery is supplied to the calling` party through the windings of stepping relay Slt and impedance coil 4. Talking battery for the called subscriber is supplied through the stepping relay and impedance coil individual to his line. It should be noted that as soon as the calling subscriber operated.

the relay 7 in testing the called line, the impedance coil 27 is bridged across brushes 2O and 21 to close a circuit for energizing a stepping relay corresponding to SR, and the motor magnet of the switch individual to called line is operated to cause the switch to advance to an ott normal position where it. remains during the conversation. TVith the called subscribers switch in an off normal position, ground is applied to the test terminal ot the called line, through the low winding of relay 5, to apply a guarding potential to this terminal.-

lVhen the callingsubscriber replaces his receiver on the switchhook at the close ot the conversation or because the wanted line is busy. the 'energizing circuit of the stepping relay SR is interrupted and causes this relay to retract its armatures. The release magnet REL is now energized for a long interval in the circuit previously 'traced from grounded battery, winding ot the release magnet, conductor 8, outer back contact and armature ot the stepping relay SR, Contact 9 and ott' normal spring, ylett hand winding ot the relay 5, to ground. The release magnet in this inst-ance attracts its sluggish armature 10 and thereby releases the holding dog et the switch which returns to nor'n'ial position in the well known manner. The apparatus and circuits are now in condition tor operating on another call.

ln accordance with an additional feature ot the. present system, conference calls,A that is, calls between three or more parties, may be established without the intervention of an operator. The conference callsare established in the following manner. Each of the conferees the time when a conference is to be held, removes his receiver from the switchhook at his substation whereupon the switch individual to his line moves to its first set of terminals corresponding to those designated ctrunk in Fig. 3. `and he then presses the push button located at his station as ir" to signal a wanted party. ln providing` ttor this arrangement, it is only necessary that the tirst terminals ot the connector' switches` that is. the terminal designated trunk in Fig.' 3, should not be connected to any outgoing line. The multiple connections between these first terminals at all the switches are the same as any subscribers line. ln disestablishinp` the connection it is only necessary to have the parties replace their receivers on the swi'tchhooks as is the case oitV an ordinary call.

1. In a telephone system, incoming lines, a plurality ot outgoing lines, automatic switches for interconnecting said incoming` lines with any of said outgoing lines, a test conductor for each ot said outgoing lines, means for applying a busy condition to the test conductor ot a busy line, and a busy signal arranged to be transmitted to an incoming line when said line is extended to a busy outgoing line, said busy signal being transmitted over a portion of the test conductor or' said busy outgoing line.

2. In a telephone system, incoming lines, a plurality of outgoing lines, automatic switches for interconnecting` said incoming lines with any of said outgoing lines, a test conductor for each ot said outgoing lines, means for applying` a busy condition to the test conductor of a busy line, and a busy signal arranged to be transmitted to an incoming line when said line is extended to a busy outgoing line, said busy signal being transmitted over a portion of the test conductor of said busy outgoing line and a talle ing conductor.

llO

3. In a telephone system, incoming lines, a plurality of outgoing lines, automatic switches for interconnecting said incoming lines with any of said outgoing lines, means for applying a busy condition to the test conductor ot a busy line, and a busy signal arranged to be transmitted to an incoming line when said line is extended to a busy outgoing line, said busy signal being initiated and continued over a portion of the test conductor of said busy outgoing line.

el. in a telephone system, incoming lines, a plurality oft outgoing lines, automatic switches tor interconnecting said incoming` lines with any of said outgoing lines, means including a manually controlled mechanism for testing said outgoing lines, means for applying a busy condition to the test con` rluctor of a busy line, and a busy signal arranged to be transmitted to an incoming line when said line is extended to a busy outgoing line, said busy signal being initiated by said manually controlled means and transmitted over a portion of the test conductor ot said busy outgoing line.

5. In a telephone system, an incoming line, an impulse transmitter associated with said line, a plurality of outgoing lines, an automatic switch, means for receiving several series of impulses and Jfor advancing said switch a distance proportional to the number of impulses received to seize a wanted outgoing line it idle and testing means including an electrically polarized relay for testing said outgoing lines.

6. Ina telephone system, a plurality ot telephone lines, an impulse transmitter and a progressively movable switch associated with each telephone line, means associated with each switch for receiving several series -ot impulses from its associated impulse transmitter and for advancing said switch a distance proportional to the number of im` pulses-received to seize a wanted outgoing line and means responsive to such seizure for operating the switch of the wanted outgoing line to render said line unselecta-ble.

7. ln a telephone system, a plurality of telephone lines, an impulse transmitter and an individual progressively movable switch for each telephone line, each of said switches having a normal position, means associated with each automatic switch 'for receiving several series of impulses and for advancing said switch a distance proportional to the number of impulses received to seize a wanted outgoing line and means responsive to such seizure and independent of the respense of the wanted party for advancing the switch individual to the wanted line to an oit-normal position.

8. A telephone system including a sub scribers line, an automatic adding-type connector switch individual to said subscribers line controlled over the two sides of the subscribers line in series, a single row or level ot bank contacts 'for said automatic switch, other subscribers lines terminating in said bank contacts, subscriber controlled means for said switch governed over the two tall:- ing conductors of said telephone lines in series for connecting said rst subscribers line to any one of said other subscribers lines, subscriber-controlled means for ringing the called substation, and automatic` means for moving said switch to normal position.

In witness whereof, I hereunto subscribe my name this 30th day of J une, A. D. 1919.

`VVIl.\TI*`RED T. POWELL.

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