Title:
Telephone system for recording and reproducing transmissions
United States Patent 2082303


Abstract:
This invention relates to telephone systems and is more particularly concerned with subscribers' station arrangements comprising sound recording and reproducing means which arrangements in addition to recording the transmissions are also adapted to record such transmissions that are intended...



Inventors:
Walter, Schiller Alfred
Application Number:
US75741534A
Publication Date:
06/01/1937
Filing Date:
12/13/1934
Assignee:
Otto, Jaeger
Primary Class:
Other Classes:
360/61, 360/69, 360/89, 379/82
International Classes:
H04M1/64; H04M1/65; H04M3/42; H04M11/10
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Description:

This invention relates to telephone systems and is more particularly concerned with subscribers' station arrangements comprising sound recording and reproducing means which arrangements in addition to recording the transmissions are also adapted to record such transmissions that are intended to be used as dictations, so that these recorded transmissions can be reproduced any number of times later. According to this Invention, this result is accomplished by correlating to the telephone apparatus of a subscriber's station the normal receiving means and loud speaker means in selectively connectable manner as well as sound recording and reproducing means constructed on the same principle as the magnetic sound reproducing devices and combining the said means through the intermediary of a wiring system, in such manner, that telephonic communicatlon is rendered possible either by aid of the receiver means or the loud speaker means each separate, or by simultaneously recording the transmissions and reproducing the same later on, or else by directly recording a dictation independently of the telephone apparatus, so that the dictation can be reproduced any number of times later.

Owing to this arrangement all telephonic communications can be recorded, if desired, preferably so that the recorded transmission is amplified. Furthermore, a device may be provided which is set for ready operation by the subscriber, so that this device automatically responds to a call while the subscriber is absent and transmits to the calling party the line number of the station with the aid of a talking machine such as a gramophone and then gives the signal for the communication to begin, whereupon the latter is automatically recorded, advantageously, without being amplified, to the effect that a sharply accentuated record devoid of distortion is obtained in which the consonants can be distinguished sufficiently clearly to render the reproduction intelligible. On his return the subscriber is enabled to reproduce all communications having been received and recorded in this manner in his absence as many times as he may choose.

50 Moreover, the magnetic sound reproducing device may be adapted for use as a dictating device independently of the telephone service.

In the accompanying drawings a-form of the invention is illustrated by way of example only In which Fig. 1 is a schematic top plan view of the telephone apparatus; Fig. 2 schematically illustrates a sound recording and reproducing device; Fig. 3 shows a larger scale elevation of the 6 sound recording and reproducing means; Fig. 4 shows a plan view of the sound recording and reproducing means partly in section; Fig. 5 shows an elevation of the driving arrangement of the sound recording means; Figs. 6 and 7 show a vertical section and a plan view respectively of the sound translator head or sound head on a still larger scale; Figs. 8a and 8b represent two portions of the wiring diagram inclusive of a switching chart, and Fig. 9 is a sectional view of a detail.

The station arrangement according to this invention comprises as main parts the telephone apparatus T and a sound recording and reproducing device R.

The telephone apparatus T as such consists of a usual apparatus of .the dial switching type comprising a loud speaker, the calls being effected by means of an ordinary dial-switch 1.

The Incoming communications can be received by means of a normal telephone receiver or by means of the loud speaker 2. Furthermore, two microphones 3 are combined with the apparatus. The switching means for effecting the various connections during operating the arrangement are arranged upwardly on the apparatus, viz. a push button switch 4 for checking (a record), two lever key multiple switches 5 and 6 on both sides of th'*dial switch I, and a lever key switch 1 for return-motion (sound record carrier wire or sound wire). A pair of signal lamps is also arranged on the apparatus, the lamp 8 of the pair serving for indicating that the end of the sound wire has arrived at its limit stop, whereas the other lamp 9 indicates that the motor for moving the sound wire is operative.

Above the two signal lamps a scale 11 is situated which is provided with an index 12 which is displaceable along a guide rod '10 the scale permitting observing the unwinding of the sound wire, so that the index indicates at all times during a conversation the position of the conversation on the sound wire. The index is actuated by means of a Bowden drive 13 the pull wire of which is wound on a spring influenced drum s14. The telephone apparatus further comprises besides two amplifier tubes 15 and 16 and the necessary groups of contact arrangements associated with the lever key switches 5 and 6 naturally also all connecting wires leading out through a cable connection 17 to be connected by means of a cable 18 and another cable connection 17 with the sound recording and reproducing device R to which the pull wire of the Bowden drive 13 is anchored at one end. This device accommodates the entirety of recording and reproducing means the essential parts of which are schematically illustrated in Fig. 2.

The device is connected to the alternating current network via a network transformer 19 feeding a low tension rectifier 20 together with an associated filter and a high tension rectifier 21 also combined with a filter.

The winding and recording' device for the sound wire F which device will be hereinafter more explicitly described comprises as main parts two winding spools 22, 23, to which magnetic couplings 24 and 25 respectively are correlated, a magnetic sound head 26, and a driving motor 27 for alternately actuating the two winding spools by means of a belt drive. For disconnecting the magnets of the couplings for rendering the latter inoperative at the end of the wire two limit switch levers 28h and 29h (Fig. 3) are provided which are mechanically operated by the winding device for controlling the magnetizing circuit of the correlated magnets of :0 the couplings 24 and 25 via the contacts of these magnets, in order to prevent the wire F from being torn when recording is effected up to the end of the wire. In addition thereto, with each magnetic coupling auxiliary motor contact groups 78 and 79 are associated.

Furthermore, with the device R a response talking machine 32 having a pick-up arm 33 is combined, this machine being automatically operated through a call-relay 34 when the station is rung up, this relay serving at the same time for controlling a main relay 35. The latter has the office together with a ring-off relay 36 to automatically control the recording of telephone transmissions.

The shafts of the two winding spools 22 and 23 are mounted together with their driving means on the one hand in the face plate 40 of the device R and on the other hand in a web plate 41 positioned behind said face plate, the two winding spools being housed in a removable casing 42 on the outside of the face plate.

As the mountings and the drives of the two winding spools are identical, these parts will be hereinafter described by taking reference to one of these spools only. From Figs. 3 to 5 it is evident that to the forwardly projecting end of a winding spool shaft 43, mounted in ball bearings 40 and 41, a disk 44 is fixed, for example by means of a key, the disk serving for the adjacent end of the winding spool to bear against and being provided with a number of perforations one of which is engaged by a driving stud 45. On the inner end of each winding spool in a recess thereof, a leaf spring -, 22a is secured to the outer end of which a stud 22b is fastened and which is held by the perforated plate 44 in a position as shown in Fig. 9.

On retracting the casing 42, spring 22a is re7o leased so as to force the stud 22b into engagement with a hole 42a of a punched rim of the casing, thus securing the winding spool against rotation. On the backside of the web plate 41 a coupling magnet 25 is mounted the armature 46 of which carries, by means of two bolts 47, a pressure disk 48. On the shaft 43, in front of the pressure disk 48 a coupling disk 49 is mounted so as to be longitudinally slidable but kept from rotation, this disk being spaced from a mating coupling disk 50 by an intervening compression spring 51, in such manner, that during the time of inoperation the two disks are prevented from engaging. The coupling disk 50, which is in the form of a belt pulley, is mounted in ball bearings so as to rotate lo around shaft 43 but kept from displacement along the said shaft. When the coil of the coupling magnet 25 is energized, its attracted armature 46 forces, by means of the pressure disk 48, studs 49a on the coupling disk 49 into engagement with complementary teeth on the coupling disk 50, and, as the latter is rotated by the winding motor 27 by means of a belt 52, the spool 23 is also turned to wind thereon the sound wire F payed out by the spool 22, As shown in Fig. 3 the sound wire unwinds from the upper side of the spool 22 and is wound onto the lower side of spool 23 adapting the motor to run at all times in the same direction of rotation irrespective whether the wire is wound on one or the other spool. For tensioning the belt 52 a tensioning roller 53 is provided.

The construction of the winding means thus far described is identical for both winding spools.

The shaft 43 is further provided with a worm so thread 43s which meshes with a worm wheel 54 which is situated on the upper end of a shaft 55 mounted in oblique disposition on the backside of the face plate 40 and provided at its lower end with a worm thread 56 into which a worm wheel 57 engages. This wheel is secured on a shaft 58 which is mounted transversely between the face plate 40 and the web plate 41 and the front end of which projects out of the face plate and which carries also a cam 59. Above the 40 shaft 58 an axle 60 is longitudinally displaceably mounted in parallel relation with the same so as to project into the casing 42 with its forward end.

To this axle a guide fork 61 is secured which embraces the cam 59 and engages into a guide groove of this cam by means of a pin, so that during the operation the axle 60 is continually pushed to and fro by a certain throw which corresponds to the length of the guide groove of the cam 59 and thus to the width of the spools 22 and 23.

On the forward end of the axle 60 the sound head 26 is secured which shares in the reciprocating movement of this axle so as to ensure r, that the sound wire T after having passed the sound head is wound in uniform layers onto the respective spool 22, 23. To the forward end of the shaft 58 a bevel gear wheel 62 is fixed which is in mesh with a bevel gear wheel 63 which is o secured on a screw spindle mounted in the casing 42 parallel with the face plate 40. On this spindle a screw nut 65 is mounted for longitudinal displacement thereon and guided in a longitudinal slot of the casing so as to depend down- c wardly therefrom for receiving the pull wire of the Bowden drive 13 in an easily detachable manner.

The stop levers 28h and 29h7 of the limit switches 28 and 29 project into the path of 7o movement of the nut 65 at either end of its traverse. The ratio of gearing of the driving mechanism between the shaft 43 and the screw spindle 64, i. e. the screw nut 65, is so chosen that during the complete winding or unwinding ., of the sound wire F the nut 65 travels from one end of its traverse to the other to alternately actuate the stop levers 28h and 29h cooperating with the limit switches 28 and 29, so that the correlated coupling magnets 24 and 25 respectively are operated for disconnecting the couplings 49, 50 of that spool which is then winding on and at the same time for stopping the driving motor 27 in order to avoid breakage of the wire. The movement of the driving mechanism is transmitted to the index 12 of the device T by means of the Bowden drive thus permitting to read on the scale 1 the length for which the sound wire has been shifted in either direction. The casing 42 is fastened to the device by means of two lateral spring-influenced latches 66, so that the casing can be readily removed together with the two spools after the sound head 26 has been opened and the pull wire of the Bowden drive 13 is detached. It will be understood that a screw spindle 64 and a bevel gear wheel 63 are provided in each spool casing. While pushing the casings into position, the driving studs 45 of the spools are held in the perforations of the correlated disks 44, so that the bevel gear wheel 65 is caused to intermesh the bevel gear wheel 62 automatically.

The sound head 26 (Fig. 6) is made in two parts and contains two pairs of magnets 70 and 71 the individual magnets of each pair being offset relatively to one another for about the width of a magnet core. The pair of magnets 71 serves for pre-magnetizing and checking and the other pair 70 for recording on the sound wire passing between the magnet cores while being talked. The pairs of magnets 70 and 71 are embedded in the two halves of a body .member 26t, each of these halves being provided on the inner side with a glass plate 26a. The respective 10 ends of the magnet cores are flush with the exterior sides of the glass plates and are joined therewith by means of putty. Owing to this construction the portion of the sound wire F passing between the glass plates though contacting, 15 with the magnet cores is prevented from causing wear thereon. At each end of the upper half of the body member 26t two guide plates 26b for guiding the sound wire laterally are arranged, each pair of these plates being separated by an i0 intervening spacing plate 26c.

In consequence of the magnet cores being offset relatively to one another a thorough magnetic saturation of the wire practically devoid of dispersion is obtained, so that notwithstanding ;5 the very low speeds of the wire down to 0.5 meter per second a clear reproduction devoid of distortion ensues, the wire being pre-magnetized before every recording operation. The device is provided laterally beneath the cable connection 0 17 with terminal studs 37 (Fig. 3) for connecting it with the alternating current network, whereas further terminal studs 38 serve for connection with the telephone wires a and b.

The wiring diagram for the entire station ar5 rangement is illustrated in the Figs. 8a and 8b inclusive of a switching chart for the different positions of the lever key switches 5 and 6. Concerning the various apparatuses as far as these have not already been more particularly de0 scribed above, the following explanations are given: The network transformer 19 serves for connecting the station arrangement with an alternating current network of 100-250 volts tension Sand 40-60 kh. and is provided to this end with tap points for certain intermediary voltages.

The alternating current energy is on the one hand directly supplied to the driving motor 27 for actuating the drive of the winding spools and on the other to the driving motor for the response talking machine 32, 33. Both motors are of the normal monophase induction type having a short circuited rotor. The record of the talking machine can be talked in the following manner. Here No .... Frederic Brown, please speak slowly and clearly, your communication will be recorded. The talking current impulses that are transmitted during the then following communication are led directly to the modulating magnets 70 of the sound head 26, so that the recording on the sound wire is effected without amplification. The low tension rectifier 20 and the high tension rectifier 21 are of the' dry plate type which renders the device fit for ready operation at all times without the necessity of waiting for tubes to heat up.

The main relay 35 consists of a direct current relay, the call-relay 34 and the ring-off or final relay 36 are high ohmic alternating current re- 2 lays. Furthermore, for the recording of dictations, the reproduction and for the loud speaker telephone transmission a two-tube low frequency amplifier 72 is provided.

The telephone apparatus T is provided with a 3( call-alarm buzzer 73 for the ordinary telephone traffic and a selector switch 74 and as calling and dial switching is effected as usual further describing and illustrating the respective devices can be dispensed with. 75 refers to a microphon3 .3 inseparably connected to the telephone apparatus, the loud speaker 2 may alternatively be replaced by a normal telephone receiver. By 76 a return motion switch for reversing the movement of the sound wire F is designated and by 77 a switch for checking the recording operation. The lighting of the signal lamp 9 indicates that the winding motor 27 is operative, whereas the lighting of the signal lamp 8 indicates that the sound wire F is completely wound off from one or the other spool. With the coupling magnets 24 and 25 of the couplings of the winding spools the necessary motor control contact keys 78 and auxiliary contact keys 79 are correlated. The two lever key switches 5 and 6 serve for controlling the individual operations in their different positions of setting, that is, the middle or normal position m and their off-positions 1 and r to the left and right respectively. The lever key switch 5 controls the groups of contact springs or keys 81i-v and 831-iv and the lever key switch 6, the groups of contact keys 84z-iv and 851-vr. In all the contact arrangements of these groups as well as all the others the individual contact springs or keys of each pair are designated by a and b respectively. The brief chart at the top of the wiring diagram indicates the different setting of the two lever key switches for the various switching combinations, wherein ,5 the character T stands for normal telephone traffic, T and Rg telephone traffic combined with recording, D recording of dictation, Rp reproduction of dictation, and ARg automatic recording of telephone transmissions. The operation of the station arrangement described will be hereinafter explained by taking reference to the wiring diagram, while it is assumed that the following connections are permanent, that is, permanently put in. The positive pole of the anode potential, i. e. the conductor 101 extending between the rectifier and the amplifier, the negative biased voltage conductors 102 and 103 of the grid, the middle point of the heating conductor 105 which point is connected to earth at E and to the zero point of the source of anode potential, and the negative pole of the source of heating current 104 for the tubes of the amplifier 72. In the normal position m of the lever key switches 5 and 6 the rectifier is permanently connected to the network 37A and 37B, the amplifier 12 is under tension but witlhout being heated, as the connection between the tube heater arrangement and the source of heating current 18i is interrupted by the contact keys 85vi and 83n of the lever key switches 5 and 6 being connected in parallel. The telephone line 38a,b is closed via the selector switch contact 74n, condenser 69, call-alarm device 73, contact keys 84n and 82v of the lever key switch 6 and contact keys 82n of the lever key switch 5.

When the station is called up, the call-alarm buzzer operates. The called party thus being advised of a call changes the lever key switch 5 over to position r, whereas the lever key switch 6 remains in position m. Thereby the call-alarm clock circuit 38b, 74u, 69, 73, 84n, 82ni, 38a is interrupted at contact keys 82n1. However, before contact keys 82Ib,c open, contact keys 82iiba are already closed, so that the telephone line conductor 38a, is not interrupted but connected to point a of induction coil 86 the other end of which is permanently connected to conductor 38b via selector switch 74n. The amplifier heater arrangement circuit is closed at contact keys 82v, the amplifier thus being prepared for operation.

The microphone 75 is connected to point a or b respectively of the primary side of the induction coil 86 via the contact keys 85IIa,b or 85ma,b of the lever key switch 6 which is in condition of rest. Point d on the secondary side of the induction coil is directly connected to the input terminal 93 of the amplifier 72 via the contact keys 82m then closed of the lever key switch 5, whereas point e of the induction coil 86 is connected to the second amplifier input terminal 92 via a damper-winding resistance 87 and the contact keys 821 then also closed of the lever key switch 5. The talking current impulses amplified in the amplifier 72 flow from the amplifier output terminal 94 via contact keys 84Ib,c, which is closed in the normal condition of the lever key switch 6, via the compensating resistance 88 to the terminal 2b of the loud speaker, i. e. from the amplifier output terminal 95 via the contact keys 85rva,b of the lever key switch 6 which contact keys are also closed in the position of rest of this switch, to the other terminal 2a of the loud speaker, the loud speaker thus reproducing the incoming telephone transmission. The damper winding resistance 87 is so adjusted that an 'acoustic back coupling effect between the loud speaker 2 and the microphone 75 is avoided.

If instead of the station being called up from outside calling from the station is desired, at first the lever key switch 5 is moved into position r, while the lever key switch 6 remains in position of rest, as before, in which way all the switching connections described immediately above are completed. As soon as the signal "line free" is heard from the loud speaker, the 7. desired line member is selected by means of the dial switch, so that, in a known manner, the contact keys 74n interrupt the line circuit, while at the same time at contact keys 74i the induction coil is short-circuited. On the termination of the selecting operation contact 741 of the dial switch is opened to remove the short-circuit from around the induction coil, whereupon the apparatus is in condition for conversing.

When it is desired to record the conversation, the lever key switch 6 which up to this time had remained in position of rest, is set to position r, while the lever key switch 5 further remains set to position r. In this manner the contact 25a of the coupling magnet 25 for advance motion, the contact 25b of which is permanently connected to the positive pole 101 of the anode potential via the limit switch keys 29IIa,b is connected to the negative pole 96 of the anode potential via the already previously closed contact keys 82 IV,a,b of the lever key switch 5 and the but then closed contact keys 84iV,a,b of the lever key switch 6. In consequence thereof, the coupling magnet 25 attracts its armature and connects the dog clutch for advance movement of the sound wire. At the same time this magnet actuates the contact keys 79II,a,b thereby closing a circuit from the alternating current network via the permanent connection 99, 27b main motor, 27a 79II,b,a, 98, so that the main motor starts to run. In addition, the coupling magnet 25 also closes the contact keys 79I,a,b thereby closing a circuit from the branch conductor 91 of the low tension alternating current winding via the permanent connection 91, 8b, the signal lamp of the motor, Ba, 79I,a,b and back to the branch connection 90, so that the signal lamp I of the motor is lit, thus indicating that the motor runs. The sound wire P is thus set in motion and prepared for receiving a record.

When the switch 6 was set to position r the following further circuits have been established: The circuit of the premagnetizing coils 71 is closed via the positive pole 101 of the source of potential of the anode, the permanent connection 101, 95, the contact keys 84mI,a.b then closed of the lever key switch 6 and terminal 7Ia of the pre-magnetizing coil 71, through the latter and from the terminal 71b via the permanently connected resistance 67v and the permanent connection 67, 103 to the negative pole of the source of anode potential. Pre-magnetizing current now flows through the coils 71 for pre-magnetizing the wire F and at the same time removing all modulations that may be present on this wire. Contact keys 84II,b,c 55, open, which is, however, of no effect at this time, as the contact keys 82II,b,c of the lever key switch 5 which are connected with the former keys have previously opened. Contact keys 84I.b,c of the lever key switch 6 are thus opened to close contact keys 84I,a,b, so that the following circuit is established: The output energy of the amplifier no longer passing from terminal 94 via the contact keys 841,b,c as before to the compensating resistance 88 and from there directly to the loud speaker 2, flows via contact keys 841,a,b to point 67m of the potentiometer 67 and from there In certain proportions partly through the section 67m, 67a of the potentiometer and partly through the section 67m, 67c then of decisive importance of the potentiometer, through the condenser 68 and modulating coils 70 to point E7a of potentiometer 67 and from there via the return motion tripping contact keys 76In,ab of the coupling magnet 24 for return motion which Skeys are closed during the advance motion, and then through the closed contact keys 83U,b,a of the lever key switch 5 directly to the loud speaker terminal 2b. The potentiometer 67 for controlling the degree of modulation of the wire F and the resistance 88 are so balanced relatively to one another that the exterior resistance of the amplifier 72 remains constant so that, provided that otherwise the existing conditions remain unchanged, the strength of sound in the loud speaker with the reproduction means put in or out remains constant.

By effect of the portion of the amplified alternating talking current flowing through the modulating coils 70 the wire F is, in a known manner, magnetized to variable saturation in conformity with the frequency of the talking current impulses and proportionally to the amplitudes thereof. If during the recording the wire F is completely wound off, the apparatus 43 to 65 for counting the number of meters of wire payed out, the speed of which is highly accelerated, actuates at first the switch keys 29i of the limit annunciator signal lamp so that this lamp 9, the terminal 9b of which is permanently connected to the branch conductor 91 of the low tension alternating current winding of the main feed transformer 19 is supplied with current via the terminal 90 of the low tension winding, the terminal 19a, the then closed contact keys 29i,a,b and a permanent connection, and is thus lit.

The lighting of this lamp indicates that only a short length of wire is still available for the recording operation. If this operation is nevertheless continued, a short time later the key contacts 29II,a,b are opened by action of the apparatus for coupling the number of meters of wire payed out referred to immediately above. In this way the circuit 96, 84IV.a,b, 82V.,a,b, 25a,b, 29II,a,b, 101 of the coupling magnetizing current is broken and thus the coupling magnet 25 released, whereby the driving arrangement of the wire winding device is set at standstill by mechanical means. Incidental to the coupling magnet releasing, the contact keys 79II,a,b and 79I,a,b operated by this magnet are opened in consequence of which on the one hand the motor circuit 99, 27b, 27a, 79n,b, 79i,a, 98 is interrupted and therefore, the main motor 27 is stopped, and on the other hand the circuit 91, 8b, Ga, 79I,a,b, 90 is interrupted, so that the motor signal lamp 8 is extinguished, thus indicating that the motor is at standstill. Due to the limit contacts keys 89sIIa,b for advance motion having been opened, it is thus impossible to operate the coupling magnet 25 for advance motion in any positions of any lever key switch with a view to starting the motor, which would result in Sbreakage of the wire.

As obviously the necessity exists to wind the wire back after it is completely unwound and at this time the respective switching operation is the only one that can be carried out in regard to the movement of the wire, the switch 76 for Seffecting the return motion is operated after the lever key switch 6 has been set to normal position m. In consequence tlhreof the following circuit is established: From the negative pole of the source of anode potential 96, via return motion switch contact keys 76a, b, return motion coupling magnet 24b, 24a, return motion limit contact keys 28I,a,b to the positive pole 101 of the source of anode po75gtential 96. Consequently the return motion coupling magnet 24 energizes to connect the coupling for effecting the return motion of the sound wire. At the same time the return motion coupling actuates during its shifting movement the following contact arrangements: contact keys 78m,a,b which are in parallel with the two contact keys 79n,a,b the latter being, however, open at this time. Thus a circuit is established from the alternating current branch conductor 99 through the driving motor from 27a to terminal 27b thereof, through contact keys 78m,a,c and from there back to the alternating current network through branch conductor 98, so that the driving motor 27 starts to move again.

The direction of winding of the sound wire is, however, now reversed, by the return motion coupling 24 being connected. The motor signal lamp circuit is closed at the contact keys 781, so that the connection from the low tension winding through branch conductor 91, signal lamp terminals 8b, 8a, coupling magnet contact keys 78i,a, 78I,b, branch conductor 90 and back to the low tension winding is established, so that the signal lamp 8 is lit thereby indicating that the motor 27 is operative. During the end of the return motion the counting apparatus for the number of meters of wire payed out actuates similar contact arrangements as during the advance movement beginning with closing a contact arrangement 28u of a return motion limit annunciator signal lamp. In this manner, the end signal lamp 9 is supplied with current through a circuit which continues from conductor 91 via 9a, 8b limit contact arrangement 28I,b,a, back to conductor 90, thus indicating that the end of the wire approaches. If the return motion is nevertheless further continued, the limit contact arrangement 28I,a,b of the respective coupling magnet is opened to interrupt the coupling magnet circuit 96, 76a, 76b, 24b, 24a, 28Ia, 28Ib, 101 so that the coupling magnet releases. Consequently the motor circuit 99, 27b, 27a, 78I,b,a, 98 is broken, the motor 27 thus being set at rest. Therefore, further return motion of the sound wire F is prevented, the only possible way of moving the sound wire being forwards by operating the respective lever key switch.

During the return motion the return motion coupling magnet 24 effects also the opening of the contact keys 78n,a,b, thus ensuring that the modulating coils 70 are disconnected in any circumstances, in order to prevent current from flowing through the modulating coils 70 and thus causing undesirable modulating effects by any erroneous switching operations or leakage currents, that may arise during the return movement of the sound wire.

Automatic recording of telephone transmissions When a telephone call is received from the line in the absence of the called party, the latter is adapted to prepare for the station arrangement operating automatically to answer the call and record the incoming communication by setting the lever key switch 5 to normal position and setting the lever of the switch 6 to position r.

This setting of the lever key switches can be effected in advance as no circuits are closed in this manner to the effect that electric energy is consumed. By these preparatory switching operations the following connections are effected.

The call current impulses (alternating current of about 30 Hertz) flow via terminal 38b of the telephone service connection via the selector switch 74i, condenser 69 to the alternating current relay 34 and from there via the closed contact keys 35IIb,c of the direct current relay 35 to the then closed contact keys 84na,b of the lever key switch 6, through the also closed contact keys 82n,b,c of the lever key switch 5 and back again to the terminal 38a of the telephone service connection. Consequently the relay 34 energizes thereby closing the contact keys 341 and 34i. Direct current then flows from the positive pole 101 of the source of anode potential via the direct current relay 35a,b and contact keys 34I,a,b to the negative pole of the source of anode potential 96, thus causing this relay to energize. At the same time current is fed to the motor of the gramophone 32 through a circuit traced from conductor 98, through the contact keys 34n,a,b having just closed of the alternating current relay 34 back to conductor 99 via 32b,a, this motor thus starting to run. Due to the direct current relay 35 having been energized holding contact keys 35Iva,b are closed, so that current can flow through relay 35 independently of the contacts of relay 34 from conductor 101 through the closed contact keys 36I,a,b of the final relay 36 and the holding contact keys 35IV,a,b to 96, thus maintaining relay 35 in energized condition.

Due to relay 35 having energized the commutation contact 3511 is changed over from position 351b.,c to position 35II,a,b. In this way the callrelay is de-energized so as to release, as the circuit 38b, 74ni, 69, 34a winding of relay 34 and its contact 34b, 351ic, 35iIb, 8lIIa, 84IIb, 82Hc, 82IIb, 38a is interrupted at contact keys 35n1,b.

The relay however, remains still energized by effect of the above-mentioned holding contact keys being closed. But, upon energization the relay 35 effects in conjunction with contact keys 35n the changing-over operation which otherwise is effected by lever key switch 5 at contact keys 82II,a,b,c. This Is due to the fact that at this time a circuit is closed, from the telephone service connection 38a, via 8211b,c, 84Hb,a, 35IIb,a, 83Ia,b, 78iIb,a, 67a, 70a,b, 35IIa,b, 100IIb,c to 38b.

In this condition of the station arrangement the sound wire F is directly talked by the communicating party, thus without amplification, which method results In a very good reproduction devoid of distortion. Furthermore, in this peculiar condition of the system listening to the telephone transmissions by third parties is entirely obviated, as the loud speaker as well as the microphone are put out, perfect discretioni thus being provided for the conversation transmitted through the apparatus by the communicator.

The pre-magnetizing cooperation is effected through a circuit from 95 (101), contact keys 84IIIb,a, pre-magnetizing coil 7 la,b and resistance 67v back to 103. By energization of the main relay 35 the coupling magnet 25 for advance motion is supplied with current through the circuit 96, 84IVb,a, 35Ia,b, 25a,b, 291Ib,a and 101, and at the same time the main motor 27 is started in the manner previously described. Moreover, the wire feed is stopped upon release of the relay at the end of the conversation, due to the contact keys 351,a,b opening.

When the call-relay 34 attracts its armature by means of alternating call-current impulses, the talking machine starts to run as aboveexplained, but would be stopped again incidental to the call-relay releasing. However, at this 6 moment a cam disk 32n driven by the motor has moved through an angular displacement of such an extent that two contact arrangements 100i and 100Iz are then closed one of which closing that circuit through the motor in parallel with the corresponding contact arrangement of the call relay which thus upon release of the call-relay continues from 99 through the motor 32, cam contact arrangement 100In,a,b to 98, so that the motor is maintained running.

At the same time the pick-up arm 33, one terminal 33a of which is permanently connected to the service connection 38a, is put with its other terminal on the terminal 38b of the service connection through the contact arrangement 100i,a,b the talking current frequency thus passing out from the pick-up arm into the line only without being unnecessarily recorded.

In the meantime the sound wire is idly kept in motion, so that desirable intermissions are obtained between the various recorded conversations.

While the automatic telephone response means have transmitted the number and name and so forth of the subscriber and have given the signal for the conversation to begin the cam disk 32n has completed one revolution, whereupon the motor contact arrangement 100l opens again, thus stopping the motor, as the circuit 98, 32a,b, 1OOIIa.b, 99 is now interrupted. At the same time the line conductor 38b is disconnected from the pick-up arm and connected to the main relay 35 again by means of changeover switching, so that the initial circuit for recording is re-established. The calling party may now speak while the conversation is recorded.

When the calling party has finished talking and replaced the receiver, the thus arising abrupt current impulse causes the extremely sensitive high-ohmic relay 36, which during the talking connection was connected across the telephone line 38 in parallel with the talking circuit from 38b through the condenser 69, 36a,b, 84Ina,b, 8211e,b to 38a, to suddenly energize to open the contact keys 361, whereby, however, the holding circuit 101, 35a,b, 361%, 36Ib, 35ivb,a, 96 is broken and the main relay 35 is released, so that the coupling magnet 24 is devoid of current and thus the main motor 27 is stopped, the station arrangement being thus restored to original condition ready for receiving a call.

Applicability for dictation When it is desired to use the arrangement as an ordinary dictation apparatus, the lever key 55 switch 5 is set to normal position and the switch 6 to position 1. In this way the coupling magnet 25 is energized via the circuit 96, 85vb,a, 85a,b, 29iIb,a, 101 and the coupling for advance motion is connected and the main motor 27 is operated in the hereinbefore repeatedly explained manner.

At the same time the amplifier 72 is prepared for operation by connecting the heater arrangement thereof via the circuit 104, contact keys 85VIa,b, amplifier 72. The microphone 15 is connected to the input terminals of the amplifier through the direct current low tension circuit 104, contact keys 85Ia,b, amplifier input terminals 92, 93, contact keys 85nc,b, microphone 75b,a, contact keys 85IIIb,c and 91. The output side of the amplifier is connected to the modulating coils 10 through the circuit from output terminal 94, via contact keys 84Ib,c, compensating resistance 88b.a, contact keys 83Isa,b, return motion tripping contact arrangement 7iua,b, modulating coils 709,b, condenser 68, potentiometer 67c, E7m and back through the resistance 89 and the contact keys 85IVd,c, to the output terminal 95 of the amplifier, so that the wire F can now be talked by means of the microphone and thus the arrangement can be used as a dictation apparatus. Furthermore, in this condition of the arrangement provision is made that the loud speaker is prevented from operating during the dictation, so as to ensure that the transmission which otherwise may be disturbed is plainly intelligible, by disconnecting the terminal 2a of the loud speaker from the output terminal 95 of the amplifier at the contact keys 85IVa,b.

The pre-magnetizing operator is connected via the circuit 95 (101), contact keys 85v,.a,c, premagnetizing coil 71a, 7ib, resistance 67v, 103.

In order to reproduce the conversations recorded on the sound wire F, this wire is first caused to run backwards which is effected by means of the return motion switch 16 in the 25 condition of the station arrangement originally described. Thereupon the lever key switch 6 is set to normal position and the switch 5 to position 1. In this way the loud speaker is prepared for ready operation by connecting the 30 heater arrangement through a circuit from 104 via contact keys 83Ima,b to the amplifier 72. The coupling 25 for advance motion is put in through a circuit from 96 through contact keys 831V~,b, 25a, 25b, limit stop contact arrangement k9IIb.a 35 to 101 and the driving motor 27 is rendered operative in the manner previously described. The alternating electromotive force induced in the modulating coils by the magnetic modulation in consequence of the moving wire circulate through 40 the circuit 70a, 67a, return motion limit contact arrangement 78IIa,b, contact keys 83$1b,c to the input terminals 92, 93 of the amplifier and from there again back via contact keys 83ib,a to the modulating coil 10b. The output of the 45 amplifier circulates from the output terminal 94 via the contact keys 84bo,c of the lever key switch 6 to the conipensating resistance 88 and from there to the loud speaker 2b, 2a and back via the contact keys 85IVb,a of the lever key switch 50 6 to the output terminal limit annunciator signal lamp 95 6f the amplifier. The talking current frequency arriving from the modulating coils is then audible in the loud speaker.

In order to permit of checking the conversa55 tions entirely or partly, provided that they have not already been checked every time a fresh record was made, a check push button switch 17 is provided which supplies the pre-magnetizing coils 71 with direct current through a circuit 60 from the negative pole 103 of the source of anode potential through the resistance 67v pre-magnetizing coils from 71b to 71a, to push button switch 77 and to the positive pole 101, thus checking the conversation by a surplus of mag65 netic saturation while the wire Is moved backwards. During the normal advance motion of the wire every conversation is actually already checked by effect of the normal pre-magnetizing operation prior to the wire passing in between 70 the modulating coils 70.

Instead of using a single driving motor as described a separate driving motor may be provided for each winding spool so as to be adapted to actuate the driving shaft of the respective 75 spool through the medium of a unidirectional clutch in such manner that during winding the sound wire on one of the spools the motor of the other spool is at standstill and thus no resistance is opposed to the starting movement by inertia of ineffectively moving masses. Alternatively, the sound head may be constructed in such manner that the cores of the magnets are longitudinally displaceably mounted and urged on the sound wire by spring action. I do not limit myself to the particular size, shape, number or arrangement of parts as shown and described, all of which may be varied without going beyond the scope of my invention as shown, described and claimed. What I claim is: 1. Sound recording and reproducing means, including a magnetic sound translator, a driving motor combined with said sound translator, actuating means coupled to said motor, a sound record carrier wire advanced and returned through said sound translator by said motor by aid of said actuating means; means including a first signal lamp adapted for indicating the operated condition of said driving motor and means including a second signal lamp for indicating that said sound record carrier wire has completed a passage through said sound translator.

2. In an arrangement of a telephone subscriber's station adapted for recording and reproducing the transmissions, in combination, a telephone apparatus including a microphone, normal receiving means, loud speaker means and sound recording and reproducing means associated with said telephone apparatus by a wiring system including control means in selectively connectible manner, a rectifier and amplifier aggregate included in said recording means for operating said loud speaker means, a magnetic sound translator included in said sound recording and reproducing means, and an adjustable damper winding resistance comprised by said wiring system located in the circuit of said loud speaker whereby to avoid acoustic back coupling between said loud speaker means and said microphone.

3. Sound recording and reproducing means, including a magnetic sound translator, a normally stationary driving motor combined with said sound translator, a sound record carrier wire, two winding spools, a disconnectible electro-magnetic coupling intercalated between said motor and each of said winding spools, energizing coils for said electro-magnetic couplings, switching means included in the circuit of said electro-magnetic couplings for alternately connecting or disconnecting said couplings for winding said wire on the driven spool by action of said motor, while the other spool is released for unwinding said wire, for advancing or returning said wire through said sound translator respectively, limit switch arrangements for said disconnectible electro-magnetic couplings, a stop means cooperating with each of said limit switch e5 arrangements, a screw nut cooperating with either of said stop means, a driving member readily removably connected to said screw nut, a screw spindle threadedly engaging said screw nut, a speed reduction gear operatively connecting said screw spindle with one of said winding spools for transmitting the rotational movements of the respective spool to said spindle for stopping said sound record carrier wire by said screw nut travelling longitudinally thereon at the end of the respective passage of said wire through said sound translator, and a scale cooperating with an index, said index being operatively connected with said driving member for indicating on said scale the length of said wire passed through said sound translator.

4. Sound recording and reproducing means, including a magnetic sound translator, a driving motor combined with said sound translator, a sound record carrier wire, two winding spools adapted to be alternately driven by said motor to wind said wire on the driven spool while the other spool is unwinding said wire, for advancing or returning said wire through said sound translator respectively, a coupling member provided on each of said winding spools, a driving shaft for each of said windings spools, a complementary member to said coupling member provided on each of said driving shafts and adapted to engage with the correlated coupling member in different angular positions of the respective driving shaft, a casing surrounding said winding spools and adapted to be removably pushed into position of use to provide engagement between said coupling members and said complementary members, a spring catch intercalated between each of said winding spools and said casing, said spring catches releasing when said casing is pushed into position of use and locking said winding spools to said casing when the latter is removed to prevent distortion of said winding spools in said casing and to provide immediate operative engagement between said driving members and said complementary members, when said casing is pushed into position of use again.

5. In a recording and reproducing communication system, a telephone subscriber's station comprising a telephone line, receiving means and speech transmission means adapted for connection to said line, a telephone answering and message recording device comprising a phonographic apparatus including a record having the outgoing message recorded thereon, and a pick up device to cooperate with said record, sound recording and reproducing means associated with said telephone subscriber's station including a magnetic sound translator, circuits operatively interconnecting said telephone subscriber's station and said answering and message recording device, and switching means comprising a pair of key controlled multiple circuit switches for selectively controlling the interconnection of said subscriber's station and said recording and reproducing device whereby to provide individual and combined operation thereof.

6. The combination of claim 5, wherein one of said pairs of key controlled switches is adapted to condition said circuits to cause said phonographic apparatus to repeat the message on the record thereof to said line, and to cause said answering and message recording device to record speech currents transmitted over said line, and a relay operated by ringing currents received over said line to initiate operation of said phonographic apparatus and said answering and message recording device, automatic means to terminate operation of said phonographic apparatus after transmission of the recorded message, and a second relay operated over said line to terminate operation of said answering and message recording device. ALFRED WALTER SCHILLER.