US2176346A - Recording system for telephones - Google Patents

Description

Oct. 17, 1939. K. R HYMAN 2,176,346

RECORDING SYSTEM FOR TELEPHONES Filed March 28, 1938 5 Sheets-Sheet 1 INVENTOR. ,Ke/mdb 2. Hyman ATTORNEY.

oct. 17, 1939. K. R. HYMAN 2,176,346

RECORDING SYSTEM FOR TELEPHNES Filed March 28, `1938 5 Shee'ts-Sheefl 2 7 Ken/76M @man Oct. 17, 1939. K. R. HYMAN 2,176,346

RECORDING SYSTEM FOR TELEPHONES Filed March 28, 1938 5 Sheets-Sheet 3 INVENTOR. L/enne//z //yman BY i z ATTO EY.

Oct. 17, 1939. K. HYMAN 2,176,346

RECGRDING SYSTEM FOR TELEPHONES Filed March 28, 1938 5 Sheets-Sheet 4 INVENTOR Kenna/fh 4 Hyman ATTORNEY.

oct. 17, 1939. K. R. HYMAN 2,116,346

` RECORDING SYSTEM FQR TELEPHONES n Filed March 28. 19758 5 Sheets-Sheet 5 ATTO 'i EY.

Patented Oct. 17, 1939 UNITED STATES PATENT OFFIQE Kenneth It. Hyman, Houston, Tex., assignor to R. E. Willson, San Antonio, Tex.

Application March 28, 1938, Serial No. 198,475

32 Claims.

This invention relates to new and useful improvements in recording systems for telephones.

It is well known that every telephone subscriber is, at some time or another, absent from his home or place of business, when a telephone Call or calls comes through to his station and, as

a result, the subscriber misses the call, or calls, and has no way of knowing that another subscriber has attempted to reach him. Particu- '10 larly, in the case of doctors, or other professional men, Where the incoming call may be important, is this disadvantageous for it may be several hours before the calling subscriber may again put through his call.

ylli It is, therefore, one ofthe objects of this invention to visibly record or register the number of the calling station at the called station, so that' in the event that the called subscriber is absent when the call is put through, said called subscriber, upon his return, is advised of the station of the person who has attempted to reach him during his absence.

An important object of the invention is to provide an improved recording systemfor setting up the number of the calling station, at the called station, wherein the central oliice telephone equpment is utilized to transmit electrical impulses which represent the calling stations telephone number, whereby the recording system may be applied to any usual telephone system without a material change in the latter.

Another object of the invention is to provide an improved system which includes a sending or transmitting unit which is associated with the calling station, being preferably located at the exchange, and a receiving unit located at the called station, both units being electrically connected through the central telephone oflice equipment when the call between stations is o completed through such equipment; the transmitting unit having means for transmitting electrical impulses which represent the number of the calling station, while the receiving unit is provided with means for transposing the im'- pulses in to visible registrations atv the called station, whereby the telephone number of the calling station is set up atthe called station.

A further object of the invention is to provide :an improved recording system, of the character described, wherein the transmitting unit is operated when the call is complete and the connection between the calling and called stations is made, whereby the impulses are transmitted during the ringing period; the receiving unit transposing said impulses into visible indications immediately upon receipt thereof, which is during the ringing period, said receiving unit being so constructed that said visible indications remain until such time as the called subscriber subsequently uses his telephone instrument, at which 5 time the receiving unit is cleared.

Still another object of the invention is to provide an improved recording system including a receiving unit having a plurality of visible registers or recording devices, whereby a plurality of 10 calls made during the absence of the called subscriber may be visibly registered or recorded in their proper order; there being means for clearing said registers when the called subscriber subsequently uses his telephone instrument, 15 whereby said registers are made ready to receive further calls.

An important object of the invention is to provide an improved telephone recording system which is operable on either manual or automatic 20 (machine switching) telephone systems and which is readily adaptable to the rotary and panel systems now in general use.

A construction designed to carry out the invention will be hereinafter described, together 25 with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of -the invention is shown, and 30 wherein: Y

Figure 1 is an elevation of the transmitting unit mechanism, constructed in accordance with the invention, and having the cover of its casing removed so as to show the interior thereof, 35

Figure 2 is a horizontal, cross-sectional view taken on the line 2 2 of Figure 1,

Figure 3 is a partial transverse, vertical, sectional view taken on the line 3--3 of Figure 2,

Figure 4 is an isometric view of the commuta- 40 tor wheel which has portions thereof broken away to more clearly illustrate the same,

Figure 5 is a wiring diagram of the transmitting unit,

Figure 6 is a complete wiring diagram of the 45 transmitting unit and receiving unit, showing the hook-up of these units with the usual telephone equipment of the main oice, Y

Figure 7 is a transverse, vertical, sectional view taken through the receiving unit housing,

Figure 8 is a horizontal, cross-sectional View taken on the line 8 8 of Figure 7,

Figure 9 is an isometric view of one of the indicator disks and its associate parts, 55

Figure 10 is a horizontal, cross-sectional View taken on the line Ill-I@ of Figure 7, and

Figure 11 is a Wiring diagram of the receiving unit.

The recording system shown in the drawings includes a transmitting or sending unit which is connected to each stations incoming line at the central oiiice of the telephone company. This unit, as will be explained, sends the telephone number of its station through the central oice equipment to the called station and this number is transmitted in the form of interrupted impulses of positive and negative electricalpotential. The electrical impulses are of a high frequency current and are superimposed upon the ringing current flowing to the called station. A receiving unit is located at the called station to receive the impulses and transpose them into visible indications or numerals which correspond to the number of the calling station. 'Ihe indications or numerals may be set up by a mechanical register which is located at the called station. The transmitting and receiving units are actuated immediately upon the completion of the connection, through the central oce, between the calling and called stations and are automatically operated without assistance from either the calling or called party. The recording or registration is completed during the rst ringing period at the called station and remains set up and visible until the receiver of the telephone instrument at the called station is lifted and replaced, at Which time the register, or other indicating mechanism is cleared. In the event that the called party lifts his receiver before the first ringing period is complete, the receiving unit is constructed so as to complete the registration.

With such arrangement, a visible recording, setting forth the number of the telephone station which is calling, is set up at the called station. If the called subscriber is absent, then upon his return he can note the recording and thus be advised of the numbers of the telephone stations which have attempted to reach him. Provision is also made in the system, as Will be hereinafter explained, for the recording of several numbers, in the event that several stations call a particular station during the absence of the subscriber of that called station.

The transmitting um't Referring to Figure 1, wherein the transmitting unit T is shown, the numeral I Il designates a casing or housing, which has a general rectangular shape. One side of the casing is open and this open side is closed by a removable cover I I, both casing and cover being preferably constructed of insulating material. This casing is mounted upon a suitable frame (not shown) in the exchange and is electrically connected, as will be explained, with the calling station.

A commutating code Wheel I2, which is constructed of vulcanized fibre, moulded Bakelite, or other insulating material, is mounted Within the casing, being located at one side of the upper end thereof. The code Wheel is journaled on a stub shaft I3 which is secured in the wall of the casing and, as is clearly shown in Figure 2, the shaftextends transversely Within the casing. A

rplurality of metallic commutating bars or contacts I4 are embedded in the commutating Wheel and these contacts are electrically interconnected With each other. The bars or contacts are located adjacent the periphery of the code Wheel and are arranged to represent the telephone number of the station with which the code Wheel is associated. Referring to Figure 5, the contacts are arranged as shown, and said contacts are connected to a source of high frequency electromotive force, which is illustrated as a generator or impulsing machine E5. The negative side of th-e generator is connected by a Wire I5a to a plurality of contacts Ia which are located on one side of the code wheel. These contacts represent the rst numeral of the telephone number. It is noted that four contacts are shown. The positive side of the generator is connected by a wire Ib with a segment Illb, which segment is located on the code Wheel exactly opposite the contacts Ida, whereby the segment Ilb occupies the same radial position as the contacts, except that it is on the opposite side of the code wheel. The current is carried from the Wires Ita and I5b to the contacts and segments on the rotatable code wheel by brushes I5@ Which ride on the periphery of said wheel.

The contacts la are connected by a Wire I6 With a second series of contacts Ia, which are located adjacent the segment Mb and on the same side of the code Wheel. This places the contacts Ita on the opposite side of the code Wheel, with relation to the contacts Iia, and said contacts Ita represent the second numeral of the telephone number. Directly opposite the contacts Ia and adjacent the contacts Illa, is a segment Ib which is connected to the segment Mb by a Wire I6. The segment Itb occupies the same radial space as the contacts Ia and is on the opposite side o1" the code wheel. A wire Il connects the contacts l'a with a third series 0f contacts, which series is shown as comprising one contact I'Ia representing the third numeral of the telephone number. This contact is, of course, located on the same side of the code Wheel as are the contacts ill-a and segmentV Ib. Directly opposite the contact and occupying substantially the same radial space on the other side of the code Wheel, is a segment Ilb which has connection through a Wire Il with the segment |612. Contacts Ia are embedded in the Wheel adjacent the segment I'Ib, being connected by a Wire I8 to the contact Illa which is disposed on the opposite side oi the code Wheel, and the contacts I8a represent the fourth numeral of the telephone number. A segment Ib, having electrical connection with the segment i'lb through a Wire lS, is located directly opposite the contacts Isa andY occupies the same radial space on the other side of the code wheel. The contacts lila are connected to the wire I5a, through one of the brushes I5e, While the segment I8?) is connected to the Wire I 5b, through the other brush I5e, whereby the positive side of the generator is connected to the segments, while the negativ-e side has connection With the contacts. The contacts and segments on each side of the code Wheel are in the same radial path and manifestly, the contacts and segments are alternately spaced. The number of series of contacts and the number of contacts in each series are subject to variation, being dependent upon the telephone number of the station associated with the code Wheel.

A pair of spring contact brushes or Wipers I9 and 29 are disposed one on each side of the code Wheel (Figure v2) and have their outer ends adapted to engage the contacts and segments embedded in said Wheel. The other ends of the brushes are secured to an insulating block 2I which is fastened to the end Wall of the casing'. When the code Wheel is rotated, the brush I9 vhaving negative potential.

will alternately engage the segments and contacts on its side of the wheel, while the brush 2D will engage the alternately disposed segments and contacts located on its side. Due to the arrangement of the segments and contacts, it is obvious that when the brush I9 is engaging a series of contacts, the other brush 2li is riding on a segment. Similarly, when the brush 20 engages contacts, the brush I9 is contacting the segment on the opposite side of the code wheel. Since each successive series of contacts are on opposite sides of the code wheel and also since each successive segment is on the opposite side of said wheel, it is obvious that the positive and negative potential are caused to be on opposite sides of the code wheel. With the brushes in the position shown in Figure 5, rotation of the code wheel in a clockwise direction, will cause the brush i9 to successively engage the four contacts Illa, while the brush 20 is in constant engagement with the segment or sector I4b. The brush I9 thus makes and breaks four contacts on the negative side of potential while the brush 20 is making continuous contact on the positive potential. Continued rotation of the wheel causes the brush I9 to encounter the segment IBb which has positive potential on it, while the brush 20 makes and breaks the contacts Ia, A lead wire I9a leads from the brush I9 and a similar wire 20a leads from the brush 2li, whereby when the code wheel is rotated and the brushes engage the contacts and segments, as explained, polarized current is sent out over said wires. In effect, the code wheel is a rotating pole-changer and sends out interrupted impulses of positive and negative electric potential, such impulses being -created by the making and breaking of the contacts with the brushes. The high frequency interrupted impulses of alternatingly positive and negative polarity represent the digits or numerals of the telephone number of the station with which the code wheel I2 is associated.

For rotating the code wheel I2, a ratchet wheel `22 is fastened to one face or side of the code wheel and isrotatable on the stub` shafts I3.

AA flat spring 23 surrounds the shaft having one end secured to said shaft, while its opposite end is fastened to the code Wheel and unwinding of the spring rotates the wheel in a counterclock- Wise direction (Figure 1). Therefore, when the ratchet and code wheel are rotated in a clockwise direction, the spring is wound and exerts its pressure to urge the wheel in a counterclockwise rotation;

For rotating the code wheel in a clockwise direction so as to cause the contacts and segments Ato be engaged by the brushes I9 and 20 so as to transmit the alternately positive and negative high frequency impulses over the wires ISa and 29a, an operating pawl 25 has one end riding on the ratchet wheel 22. This end of the pawl is arranged to engage the teeth of the ratchet and when moved in the direction of the arrow in Figure V1, said pawl imparts a clockwise movement to the ratchet and to the code wheel secured to said ratchet.` Movement of the pawl in anl opposite direction causes said pawl to ride over the incline of the next adjacent tooth of the ratchet wheel so as to engage the straight side of the tooth, whereby further clockwise rotation of the code wheel may be accomplished. The code wheel is thus rotated in a step-by-step action and the amount of clockwise rotation which is imparted to the code wheel depends on the number of contacts and segments on said wheel. These contacts and segments are varied in accordance with the numerals of the telephone number which they represent. As shown in Figure 5, the telephone number has only four numerals and therefore, only approximately onehalf of the code wheel is taken up, whereby only one-half a revolution is necessary to cause all of the contacts and segments to engage the brushes I9 and 20, Different telephone numbers, having more or less numerals, will require a rotation of the code wheel through a diiTerent number of degrees.

For reciprocating the operating pawl 25, an armature 26 of a magnetic relay 2'I is pivoted on a pin which extends through a bracket 28 mounted within the casing I0. The upper end of the armature is pivotally secured at 29 to the outer end of the operating pawl and each time the magnetic coil 2'I is energized the armature 26 is attracted thereto, whereby the armature is swung to slide the pawl over one of the teeth of the ratchet wheel and permit it to engage the iiat side of said tooth. A coiled spring 3i) has one end fastened to the extended end of the armature while its opposite end is secured to a leg 3| which depends from an insulating block 32 secured to the underside of the bracket 28. The spring exerts its tension to constantly urge the armature away from the coil and therefore, when the coil is energized, the armature is swung under tension of the spring Sil. Upon de-energization of the coil 21, the spring immediately swings the armature outwardly which moves the operating pawl in the direction of the arrow in Figure 1, and thus it will be seen that it is the force of the spring which imparts the clockwise rotation to the ratchet and code wheel. The coil 21 is merely utilized to slide the pawl back over the ratchet to permit it to engage the next tooth.

From the foregoing, it will be obvious that as the coil 21 is alternately energized and deenergized, the operating pawl 25 is reciprocated to rotate the ratchet wheel 22 and code wheel Ill in a clockwise direction. As the code wheel is rotated in such direction, the ilat spring 23 which has one end secured to said wheel is wound, and to prevent reverse rotation of the wheel, while the operating pawl is slid to engage the next tooth, a retaining or escapement pawl 33 has its upper end engaged with the ratchet teeth. This pawl is pivoted on a pin 34 mounted in a bracket 35 which is fastened to the casing wall and a coiled spring 36 has one end secured to the lower end of the pawl. The spring holds the pawl in constant engagement with the ratchet teeth and prevents reverse rotation of the ratchet and code wheel while in such engagement.

The coil 2l which reciprocates the operating pawl 25 is energized by a battery circuit which is clearly shown in Figure 5. A lead wire 27a leads from one side of the coil while a wire 2lb extends from the other side thereof. The wire Ela is connected to a switch blade 3'! which is mounted in the insulating block 32 below the bracket 28. The blade overlies an elongate contact arm 38 which` has its outer end disposed beneath' an extension lug 3S formed on the lower end of the armature 26, where'os7 when the armature is swung to operate the pawl 25, the arm 32! is also swung into and out of engagement with the blade. The contact arm is connected by a wire 38a with a switch blade 49, which is arranged to move into and out of engagement with a switch arm 4I. The latter arm is connected to one side of the battery i2 by a Wire fila. The other side of the battery is connected by the wire 2lb to the other side of the coil 27.

Thus, it will be seen that the battery 42 supplies the current for energizing the operating coil 27. This current flows from one side of the battery through the Wire 21h, through the coil 2, blade 3l', arm 38, blade il@ and arm 4H and then back to the other side of the battery to complete the circuit. If either one of the switches in the circuit are open, the coil 2'! is not energized. The switch formed by the blade dil and arm @l is the master control switch for the coil and is closed only when the code wheel is ready to operate, as will be hereinafter explained. Normally, with the coil 2l de-energized, armature 25 and pawl 25 are in the position shown in Figure l, with the switch blade 3'@ engaging the switch arm 318, and the arm il disengaging the contact 4%.

When the master switch is closed, the blade di! is engaged with the arm il and the battery circuit to the coil 2'! is closed, whereby the coil is energized and the armature 26 is attracted and swung to move the pawl 25 into engagement with the next tooth of the ratchet wheel 22 secured to the code wheel lli. The swinging of the armature also disconnects the contact arm 33 from the blade 371, thereby breaking the battery circuit and (ie-energizing the coil 2l. De-energization of the coil permits the coiled spring 3D to immediately swing the armature 25 outwardly to impart movement to the operating pawl 25 in the direction of the arrow in Figure l, whereby the ratchet and code wheel are rotated. As soon as the armature has been swung outwardly, the arm 38 and blade 3l are again engaged to again energize the coil 2. Thus, the coil is alternately energized and de-energized by its own armature and such action is continued until the rotation of the code wheel is completed, which is at the time when all contacts and segments on said code wheel have been contacted by the brushes l 9 and Zt, and the alternately positive and negative electrical impulses have been transmitted over the wires 25a and la. Thus, it will be seen that when the battery circuit to the coil 2'@ isl closed by the master switch, which comprises the blade Ml and arm al, the code wheel is rotated to set up and transmit the positive and negative impulses which represent the numerals of the telephone number.

For controlling the operation of the master switch, as well as for releasing the retaining pawl 33, a differential relay 55 is mounted below the coil 2i within the casing on a suitable bracket 5i. The relay includes two windings ll and 59-2, the former being arrangedto be energized by central oii'ce equipment, as will be explained, while the latter is energized by a battery circuit. The relay is provided with an armature 52 which is pivoted at its lower end to an ear 53 formed on the bracket. The armature is provided with an angular leg 5 which overlies the Contact arm f, l! of the master switch. When the relay is deenergized and in a normal position, the armature is spaced from the relay and the contact arm M is disengaged from the blade 40.

The upper end of the armature 52 has one end of an actuating bar 55 pivoted thereto and the opposite end of said bar is slotted at 56. A pin 5'! in the extreme lower end of the release pawl extends through the slot 5t to connect the pawl and bar. vWhen the armature and bar are in the position shown in Figure 1, with the relay 5i! cle-energized, the pawl 33 is disengaged from the ratchet wheel 22 and the code wheel is free to be rotated by the spring 23. A bell crank lever 51 is mounted on the code wheel shaft I3 and has one arm 53 pivotally secured to the actuating bar 55, while its other arm underlies the operating pawl 25. With the bar 55 in the inactive position (Figure 1) the crank is swung so as to raise the pawl 25 out of engagement with the teeth of the ratchet wheel.

Coil 5--l of the relay 5@ is energized by wires 55a and 50h, as will be hereinafter explained, and such energization occurs when the connection from the calling to the called station is made through the central telephone oflice equipment. When the coil ,5E-i is energized, the armature 52 of the relay is attracted whereby the bar 55 is moved to engage the pawls 25 and 33 with the teeth of the ratchet wheel 22. At the same time the contact arm @l of the master switch is engaged with the switch blade fiii to close the battery circuit to the coil 2'! and operate the same, as has been described.

Below the master switch A which is actuated by the relay a trio of switches B, C and D are provided. The switch B includes a switch blade it and a switch arrn P34, the latter being connected to the arm el by an insulating bar 40. The switch C includes a switch blade 53 and a switch arm 59, the latter being connected to the blades ii and i3 by the insulating bar i. The switch D includes a switch blade i5@ and switch arm Si and said arm connected to the arms 59, i3 and ii by the bar till', whereby all of the switches are operated simultaneously. When the relay 55 is energized the arms fil, 513, 59 and El are moved into engagement with their respective blades 555, 13, 58 and Si? to close the electrical circuits therethrough and when the relay is deenergized, said arms are simultaneously disengaged from their respective blades to open the circuit therethrough.

The switch blade i3 of the switch B is connected by a wire i3d to one side of the coil 5&3-2 of the relay. The other side of the coil 55-2 is connected by a wire to a battery 45. A lead wire 55d extends from `the battery to a iixed contact 43. A switch arm et is normally engaged with the contact #33 and has its end disposed in the path of a radial pin 't5' (Figure l) which extends outwardly from the periphery of the code wheel lli. The pin is located on the periphery of the wheel sc that when the rotation of the wheel is completed and the impulses, which represent the numerals of the telephone number have been sent, lsaid pin strikes the Contact arm eli to separate the same from the contact Q3. The switch 14 is connected by a wire Ma to the switch arm il@ of the switch B and manifestly, when the arm iii is engaging its' blade 3, the circuit to the coil titi-2 of the relay is completed. This circuit remains closed to hold the armature 52 inwardly of the relay 5@ until the code wheel has completed its rotation, at which time the pin 45 engages the switch arm fiel to disengage the same from the contact ffl-3 and thereby open the circuit to the coil 575-2 to rie-energize said coil. This deenergizes the relay and permits the armature 52 to return to its normal position, which causes separation of the switch blades iii and @3 from their respective arms i lid. Separation of the blade it@ and arm ii breaks the'battery circuit to the operating coil 2'5 and stops further rotation of the code wheel.

From the foregoing, it will be manifest that the relay 50 is rst operated by the energization of its coil Ell-l, which coil is energized through the wires 50a and 59h which lead from the central onice. As soon as the armature 52 is attracted, the switch B is closed and the circuit to the second winding 56-2 of the relay is closed to energize this second winding. The winding 50-2 remains energized until the circuit is broken by the separation of the blade 44 and contact 43 which separation occurs when the code wheel hascompleted its rotation. The second winding %-2 and its separate battery circuit is provided to assure the relay 50 remaining energized throughout the rotation of the code wheel as the circuit through the wires 53a and 5th from the central office may be interrupted before said code wheel has completed its operation. Thus, the winding 553-2 and its associate parts pro-vide positive means for assuring complete rotation of the code wheel.

The switch blade 53 of the switch C' is connected to one of the calling stations line terminals 'l0 by a wire 53a, while the arm 59 which engages said blade is connected with the wire 20a, which leads from the brush 20. The wire I9a is connected to the switch arm 6l of the switch D, while the switch blade 60 of said switch is connected by a wire 66a to the other line terminal 'H of the calling station, as will be presently explained. Thus, it will be manifest that when the relay 5K3 is energized the switches A, B, C and D are operated or closed. The switch A closes the battery circuit to the operating coil 2l so as to ro-tate the code wheel, and the switch B closes the auxiliary battery circuit to the winding 58-2 of the relay, while the switches C and D electrically connect the brushes I9 and 20, which engage the contacts and segments of the code wheel, to the central oilice equipment, whereby the alternately positive and negative high frequency impulses may be transmitted over the central oce equipment.

The central oce equipment From the foregoing, it will be seen that the calling station is provided with a transmitting unit T, whereby alternately positive and negative electrical impulses, which represent the telephone number of the calling station, are set up and transmitted through the switches C and D. In order to describe how these impulses reach the called station, it is necessary that a general outline of the central oce equipment of the usual telephone system be given. In Figure 6, the transmitting unit is illustrated as connected with the usual Strowger step-by-step automatic telephone system which is now in general use. For a comprehensive understanding of the details of this system, reference is made to Telephone theory and practice by Kempster B. Miller, lst edition, 1933, published by McGraw Hill Company, and this volume is quoted hereinafter, with regard to the action and operation of the telephone equipment illustrated.

In Figure 6 oi the drawings, a telephone connection between the calling station and called station is shown and in this gure S indicates the calling station, O a portion of the central office equipment and S indicates the called station. The transmitting unit T, hereinbefore described, is connected with the calling station S while a receiving unit R is connected with the called station S', as will be explained. For the sake of clarity, the complete central oflice equipmentof `first, second and third selectors which merely extend the calling stations trunks selectively to a nal selector or connector is not shown; the nal selector is shown complete with all essential relays and magnets except the test and supervisory wiring, which do not enter into the; operation at this time.

The calling station includes the line terminals or normals l' and 'H which are adapted to be connected to the main trunks l2 and 13 of the central oce equipment when the receiver is lifted oir its hook 14 at said calling station. The lifting of the hook also causes the electrical current to flow through a line relay (not shown) which is associated with the calling station at its terminals at the main distributing frame of the central oice equipment. This line relay is energized by the .central oice battery and starts a series of operations preparing and selecting oice trunk circuits to the rst numerical switch or line finder equipment. When the person calling hears the dial tone, he proceeds to operate the dial 'i6 to dial the number of the station he desires. The impulses from the dial rI6 progressively extend the calling stations line over central oice trunks to first, second and third selectors (not shown) and thence to the iinal selector or connector O. This nal selector has access to the multiple of all the lines and selects the line called for in the usual manner. When this last selector h-as been actuated, the calling stations lines 'l0 and 'H are metallically extended through the trunks l2 and 'I3 to upper and lower contacts 'Il and 'I8 of a relay 19 in the connector. If the called line is busy, a busy signal will be sent back over the trunks l2 and 13 and to the lines 'l0 and 'Il of the calling station S. The equipment for setting up this busy signal is not shown, as it forms no part of the present invention.

If the called station S is not busy, the last relay B in the iinal selector O is energized and connects the called stations lines 10' and 1l', through the oice trunks l2 and 13 to upper and lower armatures 8| and 82. Thus, when the relay 80 has been energized, the calling station S has its line Ill connected to the trunk 12 which is connected to the contact 'll of the relay 19. The trunk 'I2 is also connected to the trunk 'l2' through a condenser 83 and the trunk l2 is, of course, connected with the line 'l0' of the ,called station S. The other line 1l of the called station has connection with the trunk 73' which leads to the armature 18 of the relay 19. This trunk is also provided with a condenser 83' of suitable capacity. Normally, this armature is engaged with a ground wire 84 and therefore, when the last relay 8d in the connector is operated, the connection between the lines 10 and 1I of the calling station S and line 18' and 'H' of the called station S', is not complete because the circuit is grounded to the wire 84.

However, when the relay 80 is energized, it closes the circuit between the ringing generator 85, which is common to all telephones, and the current from said generator flows through a wire 85 which leads to a contact 86, said contact being normally engaged by the upper armature of the relay 1S. Thus, it will be' seen that the calling lines 'I0 and 'll and the called lines l0 and 'H' are open at the upper and lower contacts 'Il and 18 of the relay 'I9 during the ringing period. These lines will be closed only when the armatures 19a. and 19h of the coil 19 are swung to engage said contacts and such swinging of the armatures occurs upon energization of the relay 19. The energization of the relay 19 is accomplished when the hook 'i4' of the called station S is lifted. Therefore, when the called party answers his telephone, the connection between the stations S and S is complete.

At the moment that the relay 80 is energized, the ringing current from the generator 85 is impressed on the line of the called station S and as soon as the called station answers by lifting the hook 74', the ringing generator 85 is disconnected. At the instant that the ringing current is impressed on the called line and during the ringing period, but before the called station answers, the transmitting unit T is set into operation and the alternately positive and negative impulses, which represent the telephone number of the calling station, are superimposed upon the ringing current.

The transmission of impulses As has been stated, the transmitting unit T is connected with the calling station S and such connection is clearly shown in Figures 5 and 6. The differential relay 50 may be termed the starting relay, for said relay must be energized to close the switches A, B, C` and D in order to set the transmitting unit in operation. This relay is supplied with current through the wires 50a and 50h, the former being connected to a suitable ground 8l. The latter Wire 50h has a condenser 88 connected therein and has its opposite end connected to the ungrounded side of the trunk I0 of the central oil-lee equipment. When the ringing current is impressed on the called station, the-audible ringback current is impressed on the calling station, flowing through the condenser 83, trunk l2, and line '|0 of said calling station. This current iiows through the wire 50h, condenser 88 and to the coil 50| of the relay 50, whereby said relay is energized to attract its armature 52 and close the switches A, B, C and D to set the transmitting unit T into operation. Thus, when the ringing period begins, the transmitter is actuated.

As has been explained, the closing of the switch B closes the auxiliary battery circuit to the coil 58-2 of the relay 50 and said relay is thereby maintained energized during the complete rotation of the code wheel lll. Such rotatio-n of the code wheel sets up and transmits alternately positive andnegative high frequency impulses over the wires 60a and 58a, which lead from the switch blades til and 530i the switches C and D. The Wires Gila and 53a are connected to the line terminals le and 'll of the calling station S (Figure 6), at the main distributing frame at the central ofce. High frequency current from the generator l5 is connected to the commutating contacts and segments on the code wheel and in rotating, the wheel causes make and break contacts to be made and this interrupted current is impressed on the lines and 'H and on the ofce trunks 'l2 and '53. It is noted that a battery |50 may be substituted for the generator l5 as a source of current for the impulses and this battery could be connected to the wires |5a, and lb by means of a switch |5d, as shown in Figure l. The switch ld is shown in this figure as connecting the generator l5 to the lead wires ld and |55 but may be readily moved to the position shown in dotted lines to cut out the generator and connect the battery in the circuit.

From the foregoing, it will be seen that as soon as the relay of the central oflice connectorv Ol is energized at the time the ringing period begins, the relay 50 of the transmitter T is actuated to set the code wheel |4 and its associate parts into operation. The alternately positive and negative impulses of a high frequency current are thus impressed through the Wires 58ur and 60a. on the lines 'l0 and of the calling station S and on the oflice trunks 'i2 and '|3 thence through the condenser shunts 83 and 83' and onto the lines i0 and il of the called station S. These impulses are received at the station S and are transposed into visible numerals by the receiving unit R, as will be presently explained. It is noted that impulses are sent or transmitted immediately upon operation of the relay 80 of the oiiice connector O, which is during the ringing period. The relay 'I9 of the connector O has not operated, since this relay is energized when the hook l of the called station S is lifted. Therefore, the high frequency alternately positive and negative impulses may be said to be superimposed on the ringing circuit.

The receiving um't The high frequency positive and negative polarity impulses are, thus, on the lines 10 and of the called station S and these impulses are received by the receiving unit R which is located at the called station. The construction of the receiving unit is shown in Figures 7 to 11, while the wiring of said unit is clearly illustrated in Figure 1l.

The receiving unit includes a casing or housing |00 (Figures '7 and 11), which is preferably constructed of electrical insulating or non-conducting material and said casing is preferably located in close proximity to the telephone instrument of the called station S. A double winding relay mi is mounted within the casing |00 and this relay has one winding which is energized when the relay 80 in the connector O is energized to make line selection in theline multiple of the central oce equipment. When this relay |0| is energized, it attracts its armature |02, whereby said armature operates a switch |02 to close a circuit to the second winding of said relay, whereby a second armature |03 is attracted. This second armature operates a switch |03 which has connection with the line l0 of the called station S', over which the high frequency impulses travel, and is adapted toengage a contact lll when moved inwardly by energization of the second winding of the relay. The contact lll is connected to the windings |05 and l of a polarized relay |01, which relay is mounted within the casing |00 at the lower end thereof. A pivoted armature |03 is located adjacent the ends of the windings |05 and |06 and is adapted to be attracted to one or the other of said windings, depending upon which one is energized.

The Winding |05 is arranged to be energized by positive polarity while the winding |06 is arranged to be energized by negative polarity. Therefore, when the connection between the calling and called stations S and S' is made and the relay |0| is operated, the positive and negative polarity pulsations traveling over the lines 'l0' and 'll' of the called station are conducted through the switch |03 and the contact |04 to the windings |05 and |06. The first impulses, being positive, represent the first numeral or digit of the calling station, and energize the positive Winding |05, a number of times in accordance with the number of impulses, whereby the armature |08 is swung a similar number of u times in one direction. As shown, the code wheel I4 in the transmitting unit first sends out four positive impulses, thereby energizing the winding |05 four times and swinging the armature |08 four times. This indicates that the first digit or numeral of the calling station is four. The negative winding |56 is then actuated a predetermined number of times, in accordance with the number of negative impulses transmitted, whereby the armature |238 is swung in an opposite direction a given number of times. This swinging of the armature in an opposite direction by the negative impulses indicates the second digit of the telephone number of the calling station S. As illustrated, this second digit is also four. The third digit is represented by positive impulses, the fourth by negative impulses, and so on, whereby the polarized relay lill is operated alternately by positive and negative impulses throughout the rotation of ythe code wheel and until the entire telephone number of the calling station, as represented by the impulses, is transmitted. The armature |08 is, of course, swung in accordance to the energization of the windings |05 and |06 of the relay |01.

The armature |08 is provided with an extension or arm |09 (Figure 10) which is, preferably, integral therewith so as to swing simultaneously therewith. The arm is conned between switch blades |I0 which have an inherent resiliency, whereby said blades urge the arm to an upright position to normally hold the armature |08 away from the windings |05 and |06. When the winding |05 is energized, the armature IBS and arm |09 are swung so that one or the blades H0 is swung into engagement with a contact arm III. Energization of the other winding IE5 swings the armature and blade in an opposite direction to engage the other blade II@ with a contact arm ||2. 'Ihe blades H0 are connected to a common ground, while the contacts III and IIE are connected with a register, as will be explained. Thus, the direction of movement of the armature and the number of times of such movement, controls the actuation of a register, whereby the swinging of the armature is transposed into visible numerals, indicating the telephone number of the calling station as represented by the transmitted impulses.

The register mechanism The register is located within the casing |00 and includes a plurality of rotatable disks II3, I|3a H35, IISc, IIS@ and |I3e which disks are rotatably mounted on a transverse shaft I|4 which extends through the casing (Figures 7 and 8). The disks are provided, one for each numeral or digit of the telephone number and are rotated in accordance with the positive and negative pulsations energizing the relay II and actuating the armature l 08. Each disk has the numerals l to 0 displayed on its periphery and one of these numerals is visible through a window |00' provided in the top or" the casing il above the disks.

For rotating the disks, a plurality of magnetic relays or coils IE5, II5a, H55, I|5c, |i5d and II5e, are mounted on a support H5 within the casing |00 and each coil controls the operation of one o1 the disks. As the operating connection between each coil and its respective disk is exactly the same, a description of one will suilice.

Each coil II5 to ||5e has an armature III which has its lower portion pivoted to the end of the support I I 6, the extreme lower end of said armature having one end of a coiled spring |20 fastened thereto. The other end of the spring is secured to an ear |20 which depends from the support and the spring |20 exerts its tension to constantly urge the upper end of the armature II'I away from the coil I5. When the coil is energized the armature is drawn inwardly under tension of the spring I2@ and when de-energized, the spring immediately swings the armature outwardly.

An operating pawl I2I has one end pivoted to the upper end of the armature II? and its opposite end rides on a ratchet wheel |22 which is secured to the register disk I I3. The pawl is arranged to engage the teeth of said ratchet wheel and impart rotation thereto, in the same manner as the pawl 25 imparts rotation to the ratchet wheel 22 of the transmitting unit. Each time the coil H5 is energized, the disk H3 is rotated the distance of one tooth on the ratchet wheel |22 and the teeth on said wheel are arranged to coincide with the numerals on the periphery of the disk, whereby each movement of said ratchet wheel by means of the pawl |2| causes the next successive numeral on the disk to become visible through the window I 00 in the casing. Thus, if the coil I|5 is energized four times, the pawl |2I is reciprocated four times to move the numeral four on the periphery of the disk II3 into view through the window |00.

A ilat spring |23 (Figures 8 and 9) is disposed adjacent the disk |I3 and surrounds the shaft illl. This spring has one end secured to the shaft and its opposite end fastened to the disk and said spring is wound as the pawl I2I rotates the wheel, whereby it constantly urges the disk in a reverse direction. For preventing such reverse rotation while the pawl |2| is reciprocating, a retaining or escapement pawl |26 engages the teeth of the ratchet wheel. This pawl operates in a manner similar to the escapement pawl 33 of the transmitting unit and is pivoted at its lower end on a pin |25. A coiled spring |26 has one end secured to the pawl below the pivot and its opposite end is fastened to the casing wall, whereby the spring holds the pawl in engagement with the teeth of the ratchet wheel.

From the above, it is manifest that the relays or coils I|5 to ||5e control the rotation of the register disks H3 to |I3e, whereby the numerals visible through the window 00 ane ,set up through the operation of these relays. The relays are energized by means of the contacts III and ||2 and the switch blades IIB, which blades are moved by the armature |08 of the polarized coil. rhe wiring details and hook-up between the contacts I|l and l I2 and the relays |I5 to |5e will be hereinafter explained. At this point, it is noted that when the armature |08 is swung by the energizaton of the positive winding E05 of the relay |07, the blade is engaged with the contact Iii. Such engagement closes an electrical circuit to the rst relay or coil I I5, whereby a rotation is imparted to the rst register disk I3. This disk is rotated so long as positive impulses are carried to the winding |05 and the coil ||5 is energized the number of times that the blades Iii! engage the contact III, whereby the disk IIS is rotated to indicate the number of such instances. As illustrated in the drawings, four positive impulses pass to the winding S05, which means that the blade IIU engages the contact III four times, thereby energizing the coil IIS four times and rotating the disk I I3 so as to move the numeral four on its periphery into alinement with the window in the cas- After the disk H3 has been actuated in this manner, the negative impulses transmitted from the unit T, energize the winding |96 to swing the armature 33 so that the blade ||l engages the contact |52. The engagement of this contact closes a circuit to the next coil l |5a and the negative impulses energize this coil to impart rotation to the next register disk lla, whereby the number of negative impulses are transposed into a visible numeral. After the coils H5 and ||5a have been actuated, the circuit thereto is opened, as will be explained, and therefore the next positive impulses received by the winding |35 again swing the blade |||l into engagement with the contact Ell; the second closing of this contact does not again operate the coil H5 but operates the coil H517; which rotates its disk lli-lh. Similarly, the next engagement of the blade Il@ with the contact ||2 actuates the next coil HEC, and so cn until all of the coils and register disks, necessary to record the transmitted impulses, have been operated. Thus, it is obvious that the alternately positive and negative polarity impulses actuate the coils H5 to ||5e in successive order to set up on the registering disks H3 to ||3e, the telephone number of the calling station S. The disks may vary in number depending upon the number of digits in the telephone numbers in the particular locality where the system is employed.

Referring next to Figure 11 wherein is shown the electrical wiring diagram illustrating the connection between the contact arms and ||2 and the registering mechanism, it will be seen that the contact arm is connected by a wire Illa to a metallic actuating arm |21 of the disk ||3a. This arm has its lower end secured inan insulating block |23 mounted on the casing wall, while the upper end of said arm carries a roller |29 which rides on a circular cam |33', formed integral with one side of the disk |3a. The cam has a fiat portion |3| and when said roller engages this flat portion, the arm |21 is swung inwardly to engage a contact blade |32. When the roller is riding the periphery of the disk |I3a, the arm |21 is swung outwardly to engage a contact blade |33. It is noted that each of the disks H3 to ||3e is formed with the cam. |30 and the arm |21, as well as the blades |32 and |33 and it is through the medium of these parts, that the register disks are operated successively by the alternately positive and negative impulses sent out from the transmitting unit. Normally, all of the rollers |28 are engaging the fiat portion |3| of their respective cams |30, whereby the arms |21 are engaging the blades |32.

As explained, the contact above the polarized relay |91 is connected by the wire Illa with the swinging arm |21 of the relay H311. This arm is engaged with the blade |32 and the current fiows through this blade and through a wire BEa to one side of the relay coil I5. The other side of said coil is connected to a commonI supply wire H5', which is connected to the line normal of the station S. Therefore, when the positive impulses are transmitted to the winding |65 of the relay |01, the contact is engaged by the blade ll and the circuit to the rst relay coil H5 is closed to operate the first register disk H3. The coil H5 is energized as many times as the contact is engaged by the blade Ill, which is dependent upon the number of positive impulses in the rst transmitted series. It is noted that when the first register disk ||3 is actuated, the arm |21, engaging the flat surface |3| of the cam |33 on said disk, rides off of said portion and onto the periphery of the disk, whereby the arm E21 associated with the disk ||3 is disengaged from the blade |32 and engaged with the arm |33.

When the first series of negative impulses energize the other windings |03 of the relay |31, the blade ll is engaged with the contact ||2. This contact l2 is connected by a wire |2a with the contact blade |33 of the first disk H3. The blade |33, as explained, is engaging the arm |21 and the current flows through this arm |21 and through a wire |21a to the arm |21 of the third register disk H32). Since this third disk has not yet been rotated, its arm 21 is engaging the blade |32 thereof and the blade |32 is connected through a wire |32aa with the second relay coil |5a. The relay ||5a has its other side connected to the common supply H5. Thus, it will be seen that when the armature |38 of the relay |01 is swung by the negative impulses to engage the contact arm ||2 with the blade HB, the second coil is actuated. It is pointed out that to reach the coil ||5a, the current must flow through the arm. |21 and blade |33 of the first register disk H3, whereby said first disk must be operated before the second disk ||3a can be rotated. The current must also flow through the arm |21 and blade |32 of the following or third disk l |313` which assures that the third disk has not been actuated.

After the first and second coils ||5 and ||5a have been actuated, the next series of positive impulses to the relay |01 again swings the blades into engagement with the contact The current flows over the wire la to the arm |21 of the second disk ||3a but cannot again pass through the blade |32 to the first coil l5, as this blade has been disengaged from the arm by rotation of the disk l |3a. Instead, the current flow through the blade |33 of the disk ||3a, then through arm |21 and blade |32 of the fourth disk ||3c and finally to coil ||5b to actuate the third disk.

The next series of negative impulses to the relay closes a circuit to the coil H50 of the fourth disk lld, passing through the arms |21 and blades |33 of the disks ||3, ||3b and ||3d to reach the coil ||5c. The next positive series of impulses again connects the blade E it to the contact and the current ows to the coil ||5d through the arms |21 and blades |33 of the disks ||3a and H3C. The next series of negative impulses actua the last coil ||5e, the current passing through the arms |21 and blades 33 of the disks H3, ||3b and ||3d.

An additional contact blade |34 is provided aduiacent the next to the last register disk ||3d and this blade is adapted to be engaged by a contact arm |35 which arm is secured to the arm |21 of the disk so as to be movable therewith. When the disk i3d is inactive, and before it has been rotated this contact is in engagement with the blade. The blade |34 is connected by a wire lda to the contact |34 of the armature |33 which is actuated by the relay ll, while the blade |35 is connected to the ground at the blades through a wire |35a. The contact |34 is separated from the blade |35 when the disk ||5d is rotated.

The contact blade |21 of the last disk ||3e is connected with the wire |35a, while its contact |32 is connected to the wire |34a, whereby before 75 the disk ||3e is rotated, the circuit is closed between the blade and contact. However, when the last disk |3e is actuated, the blade and contact are separated and any further impulses which might be transmitted to the relay |01 will have no elTect on the registers.

The register disks are actuated, as described, to set up the numerals or digits of the telephone number of the calling station S, as represented by the high frequency alternately positive and negative impulses transmitted to the polarized relay |01. The registering is done simultaneously with the ringing current and is superimposed thereon; however, the numerals are set up practically during the initial ringing signal. Since the polar relay |01 is not tuned to the ringing current it will not operate on it, nor will the ringing coils be effected by the high frequency code current, since said coils are not tuned to that frequency, having different impedance values.

'Ihe double winding relay |0|, which attracts the Varmature |03, so as to provide a path for the high frequency current to the polar relay |01, is of the slow release type, whereby the armature is held in its operative position for a suflicient length of time to permit the register disks to operate. Release of the armature breaks the contact to the polar relay |01 and disconnects the register operating coils ||5 to V||5e from their battery supply. kAs explained, further operation of the register is not possible even though additional high frequency impulses may be transmitted to the relay |01 and therefore, the number set up by the disks remains so until the disks are returned to original starting position by the lifting of and returning of the receiver hook at the called station S', as will be presently explained.

The vregister clearing `mechafriz'sm From the foregoing, it is obvious that the telephone number of a calling station is set up at the called station and if the subscriber is absent when the call is made, he can readily note the number which has called him during such absence. For clearing the register and returning the disks ||3 to ||3e to their starting position, a double wound release relay 40 is mounted within the casing below the coils ||5. This relay has a winding |4| and winding |42, the former being arranged toattract an armature |43 and the latter adapted to attract an armature |44. The armature |43 is pivoted to an ear |45 and has a laterally directed leg |46 at its lower end, whereby when the armature is swung, the leg is also swung. The leg is conned between switch blades |41 and |49 and when the armature |43 is in an outer position, the leg moves the upper blade |41 into engagement with a contact arm |48. When the winding |4| is energized, the armature is attracted and the leg |41 disengages the blade |41 from the contact arm |48 and engages the blade |49 with a contact blade |50. A third blade |5| is secured to the blade |49 and is movable therewith, being arranged to engage a contact arm |52 when the armature |43 is attracted by the energized winding |4|.

For latching the armature |43 in its inner position (Figure 7) a latching bar |53 overlies the relay |40 and has a pawl |54 at one end for engaging over the upper end of the armature. The opposite end of the bar |53 is pivoted on a transverse bar and the upper end of the armature |44 of the winding |42 is secured thereto. When the armature |44 is attracted, the bar is swung upwardly tov release Ythe armature |43. A pin |55 extends upwardly from the bar |53 and is arranged to engage a contact blade |56, which blade normally engages a contact arm |51. When the bar is latching the armature |43, the blade and arm are engaged to close an electrical circuit therebetween, but when the armature |44 'is swung inwardly, due to the energization of the winding |42, the bar 53 is swung upwardly to disengage said contacts.

The armature |44 has its lower end fastened by a link |58 to an angular release member |59. The member is provided with a pin |60 slidable in a slotted supporting member |6| which depends from the support ||6 and when the armature is swung, the member is moved laterally Within the casing. The extreme outer end of the member is connected with the lower end of the retaining pawl |24 by means of a shaft |6| and slot |62, the latter being in the member. The shaft is connected to all of the pawls |24 of the disks by the shaft |6| and when the member is moved by the swinging of the armature |44, all of the pawls |24 are disengaged from the ratchet wheels |22. A bell crank |63 is provided for each operating pawl |2|, being pivoted on the disk shaft 4, and the upper arms of said bell cranks extend beneath the pawls |2|. The lower arms of said bell cranks are connected by a transverse shaft |64 which is secured to the member |59. With such arrangement, movement of the .member by means of the armature |4 simultaneously disengages the pawls |2| and the pawls |24, whereby the fiat springs |23 may return the disks to a starting or normal position. The reverse rotation of the disks is limited by a peripheral pin |65 which strikes the underside of the top of the casing |00 (Figure '7).

For operating the release mechanism when the hook 14 of the called station S is lifted so as to clear the register disks ||3 to ||3e, a pair of contacts |66 and |66 are provided above the hook and a second pair of contacts |61 and |61 are provided below the hook. Normally, the hook is in a lowered position in engagement with the contacts |61. One of the contacts |61 is connected by a wire |61@ with the winding of the operating relay |0| which relay actuates the armatures |02 and |03, as has been explained. The other contact |61' is connected by a wire |5|a to the switch blade below the relay |40. When the hook is raised, the circuit to this relay is opened at the contact |61, whereby said relay |0| is inoperative so long as the hook is raised.

The raising or lifting of the hook 14', not only disengages the contacts |61 and |61', but also engages the upper contacts |66 and |66'. The upper contact |66 is connected through a wire |66a with the switch blade |41 which is normally in engagement with the arm |46. The contact |48 is connected by a wire 48a with one side of the winding |4| of the relay |40, they opposite side of said winding being connected by a wire |4|a to the line normal 1|l of the station S. Thus, when the hook is raised to engage the con'- tact |66, the current i's conducted to the winding |4| to attract the armature I 43 and swing the same. Swinging of the armature causes the upper end to engage beneath the pawl |54 of the latch bar |53 so as to lock the armature in its inner position and also the leg |46 of said armature disengages the blade |41 from the contact arm |48 and engages the blades |49 and |5| with their respective arms |50 and |52. Disengagement of the blade |41 and contact |48 breaks the circuit to the winding |4| to de-energize the same but the armature |43 cannot swing away from the relay because of its latched condition. This condition of the armature |43 prepares a circuit to the other winding of the relay 40 when the hook |4 is again lowered by placing the receiver on said hook. l Y

When said hook is again lowered, the current flows through the contact |61' and wire |5|a to the blade |5|. This blade is engaging the arm |52,l being held so by the locked armature |43, and a wire |52a leads from the arm |52 to one side of the winding |42 of the relay |40. 'I'he other side of this Winding is connected by a wire |42a to the contact arm I5? which is located above the latch bar |53. This arm is normally engaging the blade |56 and said blade is connected through a wire |56a with the blade |49 below the relay. The blade is held in engagement with the switch arm |50, which arm is connected by a wire |a to the line normal of the station S. Thus, it Will be seen that when the hook I4 is lowered, by replacing the receiver of the instrument thereon, the current flows to the winding |42 of the relay |40, passing through the blade |5I, arm |52, blade |55, arm |5|blade |49 and arm |50. If any one of these blades are out of engagement with their respective arms, the circuit to the winding |42 is not complete.

The energization of the winding |42 attracts its armature |44 and moves the release member |59', whereby the pawls 2| and |24 are disengaged from theregister disks ||3 to |3e, said disks being returned to their original or starting positions by the fiat springs |23. Swinging of the armature |44 also raises the latch bar |53 to disengage the bar from the armature |43, permitting said armature to swing away from the winding |4|. Upward movement of the latch bar |53 disengages the blade |56 from its arm |51 which breaks the circuit to the winding |42, and all of the parts associated with the relay |40 are returned to a normal, or starting, position.

From the foregoing, it will be seen that the telephone number of a calling station is recorded or registered during the ringing period. This registration remains visible until the subscriber at the calling' station lifts his receiver, at which time the release mechanism is prepared for operation. Replacement of the receiver on the hook, resulting in downward movement of said hook actuates the release mechanism and clears the register, placing the same in readiness for thev next recording.

Up to this point the operation of the transmission to, and indication of, calling subscribers numbers at the called station is limited in its scope to setting up only one set of numbers; in other words, only one call can be registered at the called station. Any subsequent calls from the same or other sources would not be registered and would therefore be lost.

Therefore, in order to enlarge its scope and provide facilities for transmittal and reception of two or more incoming calls at the called station it is only necessary to provide two or more additional groups of registering relays, similar to the rst group, together with their associated ratchet and digit wheels, and releasing mechanisms. All groups will be cleared by the master clearing relay at the subscribers station as in the single registration by the double relay |40.

To accomplish the visual registration of two or more calls to the same subscribers station there are provided as many multiple groups of kregistering relays as itis desired to have calls registered. Any number may be installed to suit traffic conditions. Reference may now be had to Figure 6. To the cam |30 of the last operable relay |3e of the first group is added an additional make and break contact or switch IZla. Battery from the line serving the iirst group of relays is brought to one contact of this switch while the other terminal of this contact serves the battery feed to the second group of registering relays. The corresponding last relay in this second group is similarly equipped'with a switch |270 serving battery to a third group of registering relays and the last relay of each succeeding .group has a similar switch serving each following group of relays, etc., for any number of groups. Ground is multiplied through the relay groups as are also the negative and positive impulse bus bars from the contacts on the polar relay |01.

The operation is as follows: After the first call number has been received and registered by the first group of relays, as previously described, the last operable relay in the first group closes the contacts oi the switch |2la and puts battery on the second group of relays. The next call will not effect the first group since all coil contacts are open at the cams |30 but it will effect the second group. This group will then proceed to follow the impulses sent to it from the polar relay |07 and set up the second called numbers. The last operable relay in the second group closes its back contact and puts battery on the third group preparing it for the reception of the third calls, etc. Figure 6 shows the wiring arrangement of a two call registration unit. Each group of registering relays receives its battery supply through contacts from the same central oiiice battery brought to it progressively by the operation of the cam contacts from the preceding group.

There is no limit to the number of groups or relays that may be provided. A private branch exchange may have a greater number than an individual. No attempt is' made in this application to prescribe any particular size or mechanical features of the units, as this is mainly subject to shop methods of different manufacturers.

Upon the called subscriber returning he will make note of all calls set up in his register; he then proceeds to-call any one of these or another number. The numbers as set up will remain visible duringv hisl rst conversation; when he hangs up, the clearing out relay |40 will clear all registrations from all the relays and set them back ff to zero or starting positions.

The above description and outline of operation covers the application of the transmission and reception of calling numbers to called stations to the step-by-step method of automatic telephone operation, but obviously, the invention may be adapted to any type of telephone system, either automatic or manual.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. The method of transmitting the telephone number of a calling station which includes, setting up electrical impulses representing the number of the calling station, transmitting the impulses to the called station, receiving said impulses at the called station, transposing the electrical impulses into visible numerals, registering the numerals at the called station, and clearing the registered numerals when the telephone instrument at the called station is used to make a subsequent call.

2. The method of transmitting the telephone number of a calling station to a called station which includes, setting up electrical impulses which represent the number of the calling station when the connection between the stations is made, superimposing the impulses on the ringing circuit of the called station, receiving said impulses at said called station, transposing the electrical impulses into visible numerals, registering the numerals at the called station, and clearing the registered numerals when the telephone instrument at the called station is used.

3. The method of transmitting the telephone number of a calling station to a called station which includes, setting up electrical impulses of alternately positive and negative polarity which represent the number of the calling station when the connection between the stations is made, superimposing the impulses on the ringing circuit of the called station, receiving said impulses at said called station, and transposing the impulses into visible numerals to indicate at the called station the number of the calling station.

Ll. A telephone recorchng system for transmitting the telephone number'of a calling station to a called station including, means for setting up electrical impulses which represent the number of the calling station, means for transmitting said impulses to the called station during the ringing period, and means at the called station for receiving said impulses and transposing the same into visible numerals, whereby the telephone number of the calling station is recorded at the called station.

5. A telephone recording system for transmit- `ting the telephone number of a calling station to a called station including, means independent of the telephone instrument at the calling station for setting up electrical impulses which represent the number of the calling station, means for transmitting said impulses to the called station, means at the called station for receiving said impulses, and a register at the called station actuated bythe receiving means for transposing the electrical impulses into visible numerals to record the telephone number of the calling station.

6. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means associated with the calling station for setting up electrical im'- pulses which represent the number of the calling station, means for transmitting said impulses to the called station, means at the called station for receiving said impulses, a register at the called station actuated by the receiving means for transposing the electrical impulses into visible numerals to record the telephone number of the calling station, and means for clearing said registerV when the telephone instrument at the called station is subsequently used.

'7. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means associated With the calling station for setting up electrical impulses which represent the number of the calling station, means for superimposing the electrical impulses on the ringing circuit of the called station whereby said impulses are transmitted to said called station, means at the called station for receiving said impulses, and means for transposing the same into visible numerals to record the telephone number of the calling station.

8. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means for setting up electrical impulses which represent the number of the calling station, means for superimposing the electrical impulses on the ringing circuit of the called station whereby said impulses are transmitted to said called station, means at the called station for receiving said impulses, means for transposing the same into visible numerals to record the telephone number of the calling station, and means for clearing the recording when the telephone instrument at the called station is subsequently used.

9. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means associated with the calling station for setting up electrical impulses which represent the number of the calling station, means for superimposing the electrical impulses on the ringing circuit of the called station whereby said impulses are transmitted to said called station, means at the called station for receiving said impulses, and a register at the called station actuated by the receiving means for transposing the electrical impulses into visible numerals to record the telephone number of the calling station.

l0. A telephone recording system for transmitting the telephone number of a calling station t0 a called station including, means associated with the calling station for setting up electrical impulses which represent the number of the calling station, means for superimposing the electrical impulses on the ringing circuit of the called station whereby said impulses are transmitted to said called station, means at the called station for receiving said impulses, a register at the called station actuated by the receiving means for transposing the electrical impulses into visible numerals to record the telephone number of the calling station, and means for clearing said register when the telephone receiver at the called station is lifted and replaced subsequently using the instrument at the called station.

1l. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means associated with the calling station automatically actuated when the connection between the stations is made for setting up electrical impulses of alternately positive and negative polarity, which impulses represent the number of the calling station, means for transmitting said impulses to the receiving station, a polarized relay at the receiving station actuated by the electrical impulses, and means operated by said relay for transposing the impulses into visible numerals to record the telephone number of the calling station.

12. A telephone recording system for transmitting the telephone number of a calling station to a called station including, means associated with the calling station and actuated when the connection between the stations is made for setting up electrical impulses of alternately positive and negative polarity, said impulses representing the number of the calling station, means for transmitting said impulses to the receiving station, a polarized relay at the receiving station actuated by the electrical impulses, a register operated by said relay for transposing the electrical impulses and transposing them into Visible numerals to record the telephone number of the calling station, and means for clearing said register when the telephone instrument of the called station is subsequently used.

i3. A telephone recording system for transmit-- ting the telephone number of calling stations to a called station including, means associated with the calling station for setting up electrical i.A pulses which represent the number of the calling station, means for transmitting said impulses to the called station during the ringing period, means at the called station for receiving said impulses, a plurality of registers at the called station actuated by the receiving means for transposing the impulses into visible numerals, and means for operating said registers independently and in a desired order to register the telephone numbers of a plurality of calling stations at the called station.

14. A telephone recording system for transmitting the telephone number of calling stations to a called station including, means actuated when the connection between the stations is made for setting up electrical impulses of alternately pcsitive and negative polarity, said impulses representing the number of the calling station, means for transmitting said impulses to the receiving station, a polarized relay at the receiving station actuated by the electrical impulses, a pluralityT of registers at the called station actuated by the relay for transposing the received electrical impulses into visible numerals, and means for opn erating the registers one at a time in a desired order to record the telephone numbers of a plurality of calling stations at the called station.

l5. A telephone recording system for transmit-- ting the telephone number of a calling station to a called station including, means associated with the calling station and actuated when the connection between the stations is made for setting up electrical impulses of alternately positive and negative polarity, said impulses representing the number of the calling station, means for transmitting said impulses to the receiving station, a polarized relay at the receiving station actuated by the electrical impulses, a plurality oi registers at the called station actuated by the relay for transposing the received electrical impulses into visible numerals, means for operating the registers one at a time in a desired order to record the telephone numbers of a plurality of calling stations at the called stations, and means for clearing all the registers when the telephone instrument at the called station is subsequently used.

16. The combination with an automatic telephone system wherein calling and called stations are connected through central oflce equipment of a recording system including, means associated with the calling station and automatically actuated when the connection between stations is made for setting up electrical impulses which represent the telephone number of the calling station, said means being so connected to the central office equipment through the calling station that the electrical impulses are transmitted over the ofce trunks, being superimposed on the ringing circuit of the called station, and means at the called station for receiving the impulses into visible numerals, whereby the telephone number of the calling station is recorded.

i7. The combination with an automatic telephone system wherein calling and called stations are connected through central oice equipment of a recording system including, means associated with the calling station and actuated when the connection between stations is made for setting up electrical impulses which represent the telephone number of the calling station, said means being so connected to the central oce equipment through the calling station that the electrical impulses are transmitted over the office trunks, being superimposed on the ringing circuit of the called station, means at the called station for receiving the impulses and transposing them into visible numerals, whereby the telephone number of the calling station is recorded, and means for clearing said recording when the telen phone instrument of the called station is Subsc-- quently used.

18. The method of transmitting the telephone number of a calling station to a called station which includes, setting up electrical impulses which represent the number of the calling station immediately after the ringing circuit to the called station is complete, transmitting said impulses over said ringing circuit to the called station, receiving said impulses at the called station, and transposing the same into visible indications to indicate at the called station the number of the calling station.

19. The method of transmitting the telephone number of a calling station to a called station. which includes, automatically setting up electrical impulses which represent the number of the calling station as soon as the ringing circuit to the called station is complete, transmitting said impulses to the called station, receiving said imn pulses at said called station, and transposing said impulses into visible indications to indicate the number of the calling station, at said called station.

20. The method of transmitting the telephone number of a calling station to a called station which includes, automatically setting up electrical impulses which represent the number of the calling station as soon as the ringing circuit to the called station is complete, transmitting said impulses to the called station over said ringing circuit and during the first ringing period, receiving said impulses at said called station, and transposing said impulses into Visible indications to indicate the number of the calling station at said called station.

21. The method of transmitting the telephone number of a calling station to a called station which includes, automatically setting up electrical impulses which represent the number of the calling station as soon as the ringing circuit to the called station is complete, transmitting said impulses to the called station over said ringing circuit and during the rst ringing period, receiving said impulses at said called station, transposing said impulses into visible indications to ind;- cate the number of the calling station at said called station, and clearing the visible indications when the telephone instrument at the called station is used to make a sub-sequent call.

22. The method of transmitting the telephone number of a calling station to a called station which includes, automatically setting up electrical impulses which represent the number of the calling station as soon as the ringing circuit to the called station is complete, transmitting said impulses to the called station, receiving said impulses at said called station, transposing said impulses into Visible indications to indicate the number of the calling station at said called station, and automatically destroying the visible indications upon the subsequent use of the telephone instrument at the called station.

l 23. The method of transmitting thetelephone number of a calling station to a called vstation which includes, automatically setting up electrical impulses which represent the number of the calling station, transmitting said impulses to the called station, receiving said impulses at the called station, transposing said impulses into visible indications to indicate the number of the calling station at the called station, and automatically clearing the indications to destroy the same upon the next subsequent use of the telephone instrument at the called station.

24. The method of transmitting the telephone number of a calling station which includes, setting up at the calling station electrical impulses representing the number of such calling station as soon as the ringing circuit to the called station is complete, such impulses being of a different frequency than the frequency of the ringing current so as not to interfere therewith, transmitting said impulses to the called station during th-e ringing period, and receiving and transposing said impulses into visible indicatio-ns at the called station to indicate the number of the calling station.

25. A telephone system for transmitting the telephone number of a calling station to a called station including, means for setting up electrical impulses which represent the number of the calling station and being automatically operated when the ringing circuit to= the called station is complete, means for transmitting said impulses to the called station, means at the called station for receiving said impulses, and registering means at the called station actuated by the receiving means for transposing the electrical impuls-es into visible indications to record the telephone number of the calling station.

26. A telephone system for transmitting the telephone number of a calling station to a called station including, means for setting up electrical impulses which represent the number of the calling station and being automatically operated when the ringing circuit to the called station is complete, means for transmitting said impulses to the called station, means at the called station for receiving said impulses, registering means at the called station actuated by the receiving means for transposing the electrical impulses into visible indications to record the telephone number of the calling station, and means for clearing said registering means to destroy the indication when thetelephone instrument at the called station is subsequently used.

27. A telephone system for transmitting the telephone number of a calling station to a called station including, means for setting up electrical impulses'fwhich represent the number of the Y calling stati'n and being automatically operated 28. A telephone system for transmitting the' telephone number of a calling station toa called station including, means for setting up electrical impulses which represent the number of the calling station and being automatically operated when the ringing circuit to the called station is complete, means for transmitting said impulses to the called station and over the ringing circuit during the initial ringing period, means at the called station for receiving said impulses, registering means at the called station actuated by the receiving means for transposing the electrical impulses into visible indications to record the telephone number of the calling station, and means actuated by the receiver hook of the telephone instrument at the called station for clearing the registering means upon the next subsequent use of said instrument.

29. A telephone recording system for transmitting and recording the number of a calling station to a called station including, means independent of the telephone instrument at the calling station for setting up electrical impulses which represent the number of the calling station, such impulses being of a frequency different from the normal ringing current of the telephone system, transmitting said impulses to the called station over the ringing circuit of the called station and during the ringing period, means at the called station for receiving said impulses, and means for transposing the same into visible indications to indicate the number of the calling station at the called station.

30. A telephone recording system for transmitting and recording the number of a calling station to a called station including, means independent of the telephone instrument at the calling station for setting up electrical impulses which represent the number of the calling station, such impulses being of a frequency different from the normal ringing current of the telephone system, transmitting said impulses to the called station over the ringing circuit of the called station and during the ringing period, means at the called station for receiving said im* pulses, means for transposing the same into Visible indications to indicate the number of the calling station at the called station, and means actuated by the receiver hook of the telephone instrument at the called station for clearing the indications upon the next subsequent use of said instrument.

31. The combination with an automatic telephone system wherein calling and called stations are connected through central office equipment of a recording System including, means at the calling station independent of the telephone instrument at such calling station for setting up electrical impulses which represent the telephone number of said calling station, said impulses being of a higher frequency than the normal ringing current of the telephone system, means for superimposing said high frequency impulses on the ringing circuit of the called station, and means at the called station for receiving said impulses and transposing them into visible numerals, whereby the telephone number of the calling station is recorded at the called station.

32. The combination with an automatic telephone system Wherein calling and called stations are connected through central oiice equipment of a recording system including, means at the calling station independent of the telephone instrument at such calling station for setting up electrical impulses which represent the telephone number of said calling station, said impulses being of a higher frequency than the normal ringing current of the telephone system, means for actuated by the receiver hook 'of the telephone instrument at the called station for Vautomatically clearing said indications upon the nnext subsequent use of said instrument.

KENNETH R. I-IYMAN.

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