US2284173A

US2284173A - Apparatus for recording and reproducing telephone messages

Info

Publication number: US2284173A
Application number: US262206A
Authority: US
Inventors: Soukup Johann; Zerner Friedrich
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-01-31
Filing date: 1939-03-16
Publication date: 1942-05-26
Anticipated expiration: 1959-05-26

Description

M y 26, 1942. J. SOUKUP HAL 2,284,173

APPARATUS FOR RECORDING AND REPRODUGING TELEPHONE MESSAGES Filed March 16, 1939 9 Sheets-Sheet l E v A B t I FIG.'1.

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119 ulo K b 4 LC m y IT b 66 I I 01-65 a [L a as I III Mm 41 h bv'aifih a May 26, 1942. J. SOUKUP ET AL 2,234,173

APPARATUS FOR RECORDING AND REPRODUCING ,TELEPHONE MESSAGES Filed March 16, 1939 9 Sheets-Sheet 2 Jaw/M jy' :LJI'M) A J. S'OUKUP ET AL May 26, 1942.

APPARATUS FOR RECORDING AND REPRODUCING TELEPHONE MESSAGES 9 Sheets-Sheet 3 Filed March 16, 19:59

May 26, 1942. I J, SQUKUP ETAL 2,284,173

APPARATUS FOR RECORDING AND REPRODUCING TELE PHONE MESSAGES Filed March 16, 1939 9 Sheets-Sheet 4 May 26, 1942. sou u ETAL 2,284,173

APPARATUS FOR RECORDING AND REFRODUCING TELEPHONE MESSAGES Filed March 16, 1939 9 Sheets-Sheet 5 5,000! f Spud; V

t d S 5 re 40cm has! 5 May 32/0/47 t 22 /rr 7 gulf I 2 36 3 6 4 m Zuni/W;

May 26, 1942. J. SOUKUP Em. 2,284,173

APPARATUS FOR RECORDING AND REPRODUCING TELEPHONE MESSAGES Filed March 16. 1939 9 Sheets-Sheet 6 FIG .15.

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- APPARATUS FOR RECORDING AND REPRODUCING TELEPHONE MESSAGES Filed March 16, 1959 9 Sheets-Sheet '7 May 26, 1942- .1. SOUKUP ET AL 2,284,173

APPARATUS FOR RECORDING AND REPRODUCING TELEPHONE MESSAGES Filed March 16, 1959 9 Sheets-Sheet 8 /4 I x125} W y 26,1942. J. SOUKUP Em. 2, 84, 13

APPARATUS FOR RECORDING AND HEPRODUCING TELEPKGRS EESSAGES Filed March 16, 1939 9 Shees'iheet 9 FIG-Z1.

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A s a6 K ,ib :5 m4 T BM 3 :2 v H I 7" =17? D 6&7 a8 1 W Patented May 26, 1942 2,284,173 srrana'rus FOB nacoanmc AND REPRO- DUCING TELEPHONE MESSAGES Johann Soukup, Vlenna, Germany, and Friedrich Zemer, Asniere, France Y Application ch 16, 1939,' Serial No. 262,206

In Austria January 31, 1936 50 Claims. (CI.179-'-6) This invention relates to sound recording and reproducing apparatus for use with telephone systems, for the purpose of recording calls incoming during the absence of the called subscriber, enabling the latter to reproduce such records at his leisure;

Means for automatically connecting apparatus of the type set forth in a telephone exchange line by the ringing current and for disconnecting the apparatus from said line after the termination of the call are well known in the art and do not form subject matter of the present invention though embodiments of such means are 1 described for completeness.

It has already been suggested to render apparatus of the kind referred to operative for automatically recording messages by setting a single control to -a recording" position thereby causing such mechanical adjusting and electrical connection of the diiferent elements of the apparatus that without further manual operation, for example by an incoming telephone call, the amplifier for the modulated currents to be recorded is switched in, the driving motor for the sound recording medium is started as soonas the amplifier valve cathodes have reached their emission temperature, a signal is given to the speaker informing him that the apparatus is ready for recording his message, and themotor and amplifier are switched off when the message has been terminated. The apparatus is then ready for recording thenext message in a like manner as long as there is any recording medium available but the apparatus is prevented from operating on the arrival of any further messages as soon as the recording medium is used up, a counting mechanism metering the entire length of the records and either indicating this condition visually or audibly to the operator or stopping further function by disengaging the mechchanical coupling'sand/or electrical connections therefor.

By setting said single control to a rest" position the apparatus is switched oft and the ordinary telephone substation is connected in the usual manner to the exchange lines.

For reproduction of the recorded messages, however, it is necessary to set the control manually to a "rewinding position in which the motor only is switched in for repositioning the recording medium to its initial position, and then to set the control to a reproducing position whereby the amplifier and the motor are both switched in and reproduction of all of the recorded calls from the beginning to the end is effected, unless the apparatus is stopped manually at an intermediate point.

A counting mechanism actuated by the incoming messagesvisually indicates the number of the messages which have been recorded and facilitates manual. adjustment of the recording medium to a point wherefrom repetition may be started. 4 v

'fAfter termination of the reproduction the operator has again to set the manual control to the frewinding position in order to prepare the apparatus for further recording.

Due to the counting mechanism which meters the entire length of the recording medium dur-' ing recording, and meters in the reverse direction during rewinding, the recording" medium is automatically stopped by disengaging and/or switching ofl the driving motor as soon as it ha been repositioned to its initial position. Thereafter, by againsetting the control to the recording position, the apparatus is prepared for new incoming messages.

Before recording new records on the medium, the old ones thereon'have to be effaced and this, is effected by the use of a strong magnetic field which pclarises a steel wire serving as'a recordises the heating period of the amplifier valve cathodes for communicatingamessage prepared by the'called subscribed forz the calling one, it is evident that they do not operate entirely automatically for reproduction but require manual readjusting and consequently a greater amount of personal attention and skill than obtained from the average user.

It is an object of the present invention to simplify the operation of apparatus of the kind recan be ferred to and to render such apparatus entirely automatic, reducing manual operation only to apparatus is provided for recording telephone messages in a subscriber's absence and for subsequently reproducing such messages, which apparatus is controlled by a single control handle individual messag having a plurality of operating positions, in one. of which the apparatus is connected to a tele-'" phone line and prepared for recording incoming messages, in another of which the apparatus is disconnected from the telephone line and a tele:

corded in a subscriber's absence for subsequent reproduction, in which a single control handle is provided for connecting the apparatus to.a telephone line, and for effecting all the necessary 5 mechanical and electrical changes whereby the phone instrument is connected to said line, and

in' another of which recorded messages are produced while the apparatus is disconnected from the telephone line, the operation of said apparatus being divided into periods during which actual recording and actual reproducing take place, 1

periods during whichpreparationfor recording and preparation for reproducing are effected and periods of rest, said periods being grouped together into three adjacent phases, a recording phase, an intermediatephase and a reproducing phase, in such a manner that the control handle when set to any of its positions terminates one phase and simultaneously initiates an adjacent phase, a metering device being provided which limits the operation of the apparatus during recording and reproduction, and during preparation. therefor 'to steps of predetermined length, counting mechanisms being provided which count the number of messages recorded, reproduced and repositioned during preparation for recording and reproducing and serve on reaching predetermined settings to change the mechanical and electrical connections of the apparatus, thereby automatically terminating periods other other than the first one of a phase.

In accordance with another aspect, the invention comprises apparatus for recording telephone messages in a subscriber's absence and for device or devices for recordingreproducing, and the record carrier are automatically brought into their correct relative positions for recording, and

for repr'oducingfrom the earliest recorded message not previously reproduced.

Counting or metering devices have been proposed in apparatus of the type set forth, for in- 1 ,di'eating visually or audibIy the number of the messages recorded or reproduced. Also such counting or metering devices have been proposed for switching offthe apparatus automatically whilst the recording medium was being' fully wound to or'fro. One object of the present invention is to control all of the functions of the apparatus automatically so that the periods abovereferred to are governed as to their beginning and termination by counting mechanisms when they are not initiated or terminated by manual operations of the general control handle to one of its positions or, as is known per se, by an incoming call.

The length of some'periods, for example periods of actual recording or reproducing,- is

so than the last one of a phase or initiating periods subsequently reproducing such messages, which apparatus is controlled by a single control handle having a plurality of operating positions, in one of which the apparatus is connected to a telephone line and prepared for recording incoming messages, in another of which the apparatus is disconnected from the telephone line, and a telephone instrument is connected to said line, and in anotherof whichrecorded messages arereproduced while the apparatus is disconnected from the telephone line, the operationof said which actual recording and actual reproducing take place, periods during which preparation for recording and preparation for reproducing are effected and-periods of rest, said periods being grouped together into three adjacent phases. a

apparatus being divided into periods duringrecordingphase, an intermediate .phaseand a reproducing phase, in such a manner that the control handle when set to any'of its positions terminates one phase and simultaneously initiates anadiacent phase, metering devices being provided one of which meters the length of the positioned during reparation for. repetition, and

recorded, reproduced and remetered by the counting or meteringdevices, and the length of other periods such as rewinding of the recording medium preparatory1to reproducing, or preparatory to another recording is metered back equal amounts so that the recording or reproducing devices are correctly located.

of records is used. Experiments have proved that I a period of approximately 15 to 25 seconds is sufllcient for a telephone message to be recorded, provided the' calling subscriber has been informed beforehand by a message 00' unicated to him by the apparatus that his 0 ll will be recorded,

and an appropriate time has been allotted to him to determine what he is going to say.

Such a limitation of time has the advantage 'that" the calling subscriber is forced to limit his message to essential paints and avoid unnecessary vervosity, thereby economising in the recording medium. The improved apparatus is consequently most suitable for use in connection with ordinary subscriber's stations.

There are, however, applications of the apparatus according to this invention in which auto-' matic recording and reproduction of messages is desirable, the length of which messages is not uniformly prescribed and is limited only by the capacity of the recording medium. This applies for example to telecommunicating systems in use in offices and services, such as fire brigades and the other of which cumulatively meters: the

length of the messages recorded, "reproduced and 1 repositioned during preparation for repetition,

and serves on reaching a predetermined setting to change the mechanical and electrical connections of the apparatus, thereby automatically ter-'. minating the period of actual reproducing, and a 3 switch being provid'ed which is normally held open by the recording-medium itself and is closed thereby at the ends of the periods of 7' preparation for recording and preparation for reproducing so as to terminate said periods.

According to yet another aspect, the invention comprises sound-recording and reproducing apparatus whereby telephone messages may be re the like, where trained callers are accustomed production to enable further recording. Other methods require the recording medium to be re- 71; placed when its capacity has been exhausted.

This metering is facilitated if a uniform length relate to embodiments of the invention, in which and in such cases the records may be stored for future reference. v I

In the case of a recording medium not capable of being regenerated within the apparatus, it is particularly desirable to be able to continue recording on a medium on which-a series of messages has already been recorded during previous occasions, in order to use up the entire capacity of the medium before exchanging it. Heretofore in known apparatus of this type. it has-been Y necessary to start reproduction either from the commencement of the first record even if the first series had already been reproduced on a previous occasion or to adjust the apparatus manually to the commencement of the later recordings.

In preferred embodiments of this invention, repetition of any individual record may be obtained at the end of the reproduction of that record, by simply operating a repetition button or key without necessitating any manual adjustment of the recording medium or of the reproducing device to the commencement of the record to be repeated.

In certain embodiments of apparatus according to the present invention, all the messages which have been recorded on the recording medium are reproduced serially, suitable intervals being provided between the reproduction of 'the individual messages to enable the operator to note the contents of the messages and also to decide whether he wishes repetition of the mes- /sage immediately preceding the interval. For

example, when a tape is used for the recording medium, the length of which tape corresponds substantially to the length of the individual records thereon in parallel tracks side by side, such intervals are provided by the time necessary for rewinding said tape between each two successive reproductions.

In apparatus in which the records are recorded in alignment, reproduction of the inditomatically switching off the sound recording and reproducing device. 1

Fig, 6 is a diagrammatic view of a mechanism two tapes serving alternately vidual records would be eilected continuously without intervals unless an uneconomical length of unused :recording medium is provided between successiverecords (as is done with certain known systems). In order to avoid such waste of recording medium, in apparatus of this type'according to the invention, the movement of the recording medium is stopped after the reproduction of each message, and the reproduction V of the next message is obtained by operation of a suitable button or key. To repeat reproduction of a message, a suitable key is depressed at the end of the reproduction of that message. This however is considerably simpler than the manual adjusting of the apparatus which has been necessary hitherto.

The general ideas of the invention as briefly outlined hereabove and manydnventive details enabling automatic functioning of the apparatuswill be more readily understood from the following description of some embodiments, shown diagrammatically and only by way of example, of the invention as illustrated in the drawings aflixed to this specification and forming part thereof. The invention is, however, not limited to these embodiments, and details described in connectionwith one embodiment may be readily exchanged for details of other ones.

Figs. 1-12a. of the drawings relate to embodiments of the invention in which is used a recording medium not capable of regeneration and on which the individual messages are recorded side by side in parallel tracks, while Figs. 13-20 being regenerated within the apparatus.

1 In the drawings. Fig. l is a circuit diagram representing circuits of the apparatus connected to public supply a recording medium is used which is capable of means, the circuitsderived therefromand the 4 Q circuits connected to the exchange oflice. Fig. 2 is a side elevation, partly in section, of a device for automatically repositioning the recording and pick-up device to the commencement of the first record which has not yet been reproduced or alternatively to the commencement of the unused space on the recording medium.

Figs. 3 and 4 are details of the device shown in Fig. 2, in front elevation respectively.

Fig. 5 is a side elevation of a device for auior coupling reels of tape serving as a recording medium, with a driving motor for rotating the reels in either direction. 1

Fig. 7 is a circuit diagram similar to Fig. l,

but modified somewhat and representing only the circuits connected to and derived from the public supply mains.

Fig. 8. is a diagrammatic view of mechanism for coupling reels'of recording medium with a motor to rotate the reels in either direction.

Figs. 9 and 10 are a front, elevation and a section, respectively, of a device for automatically repositioning the recording and reproducing pickup means to the commencement of the first record not yet reproduced, and also for automatically switching off the apparatus, which device may also be applied to an arrangement using medium.

Figs. 10a, 10b and 100 show details of the arrangement shown in Fig. 10, representing different positions of the mechanism.

Fig. 11 is a circuit diagram of the mechanism shown in Figs. 9 and 10.

Fig. 12 is a diagrammatic view of an apparatus for recording messages in alignment.

Fig. 124 is a sectional view on theline XI-IH in Fig. 11. Y

Fig. 13 shows diagrammatically a motor and an amplifier circuit diagram for the 1 apparatus shown in Fig. 11.

Fig. 14 is a circuit diagram of a metering device for the apparatus.

Fig. 15 is a circuit diagram of controlling electromagnets for the apparatus.

Fig. 15a is a diagrammatic view of the mechanical arrangement of these electromagnets.

Fig, 1615 a modification of the circuit diagram shown in Fig. 14. c

Fig. 17 is a circuit diagram of a metering device of an embodiment of the apparatus for recording messages which are not of predetermined and in cross-section as recording Fig. 21 is a modified circuit diagram of the exchange line circuit and reproduction circuit.

Referring to the drawings, the reference letter u before a reference numeral denotes that the element enumerated is controlled by the general control handle U.

When a switch is operatedby a motor-driven element such as a cam, a control shaft or the recording medium, the letter m is placed before the reference numeral, such as m2.

All the relays are denoted by the letter H and another index. When a switch is operated by a relay the letter h is placed before its reference numeral, such as m.

Switches operated by the centrifugal governor G are denoted for example 02. Switches operated by counting mechanisms are denoted, for example cl.

Switches operated'by denoted, for example 22.

Switches operated by the receiver hook of the telephone instrument Y are denoted, for example, 112

a thermal switch Z are a and b contact one another while contact c of this switch is disconnected. uiabc signified that U to abc for recording so that both the motor M and the amplifier W are thereby connected to the public supply mains N. After a predetermined number of revolutions ofthe motor M corresponding to the time for-heating up the cathodes of the amplifier W, and for recording the. incoming call, switch ml is temporarily opened by a cam driven by said motor, whereby the circuit of primary transformer coil [2! is opened, relay HA ole-energised, and switches hal and halopen'ed. The apparatus is then switched all three contacts a, b and c of switch u! simultaneously contact one another.

Switches admitting only a closed and an open position are shown in their normal positions and oblique numerals placed below their reference numerals indicate the period during which the switches are moved to their other positions. When a numeral is bracketed, it indicates that the switch appertaining thereto might be closed or open during that period.

' The exchange lines are denoted by A, B while E is the earth wire.

Referring to Fig. 1 of the drawings, the exchange lines AB are connected by means of 'a switch at either to the ordinary subscriber's station Y when set by the general control handle U to be or to the sound recording apparatus when set by the handle to ab. When set to ab,. an alternating current as used for a ringing signal arriving from the exchange lines AB, energises a relay H whereby switch M is temporarily closed allowing a current to pass from the public supply mains N to the primary coil of a transformer l2l, switches 06 and 01 being normally closed. (Switch a6 is also closed by the general control handle U. when set to "recording position (1).) The secondary coil of the transformer- I2! is connected to a rectifier 0.22, preferably a dry rectifier, the direct current circuit of which includes the coil of a relay HA, switch hal and haZ which are operated thereby being open before the arrival of the ringing signal. As switch hal shunts switch hi, the circuit from the public supply mains N of the primary coil of transformer I2l is maintained even when switch M is opened again after termination of the ringing current, as long as a switch 'ml is in its normally closed position.

Switch u! is set by the general control handle ringing. signal.

of! and prepared to react on the next incoming The arrangement as above described ensures a safe and silent contact and also ensures switching-in of the apparatus even in parts of the exchange network where the alternating ringing current is very weak. It can be simplified when 'su-fllcient strength of ringing current is available in all parts of the exchange .network and, on the other hand when the current supplied by the'public supply mains is a direct current. Alternatively, it may be replaced by another calling rel'ayarrangement.

The relay H is connected directly to the exchange lines AB throughthe condenser K. When contact b of the switch'u engages contact a, a number ofswitche'sGl, m2, m3, ml, m5 arranged in series, are connected in parallel with the relay H across the exchange lines AB. Normally, switches GI and G2 are open and switches m3, ml and mi are closed. These switches ensure the reliabilityof the apparatus as a whole in a simple manner. Thus, switch GI is closed only when the motor M maintains a regular speed, by a centrifugal governor or the like G, arranged on the shaft of the'motor or on a shaft coupled thereto. Instead of a centrifugal governor, any

other control means, the action of which depends on speed (for example a fan, Frony brake, dynamo with relay or the like) may serve for the same purpose of switching off the'exchange circuit as soon as themotor ceases to function in the normal manner.

The switch m2 isclosed when the motor M has made a'predetermined number of revolutions. depending upon the number of ringing signals which are to be given before the device is switched in. The closure of switch m2 is effected, for example, by rr ans of a. cam driven by the motor and preferably arranged on the control shaft of the sound recording and reproducing device. The direct current circuit of the exchange lines AB is thus closed and the alternating current circuit of the ringing signal is cut out.

The switches m3, m4 and ms serve to maintain the direct current circuit of the exchange lines AB when once established, even when a number of auxiliary devices of the system are alternately connected to and disconnected from the circuit one after another. For this purpose these After a definite further number of revolutions I cate portions of that of the. motor M, switch mtis first opened by means for example, of a cam mounted on a shaft rotated by the motor,- and in consequence, the direct current from the exchange lines is led through a pick-up Q which is connected in parallel with the switch m3 and is the pick-upv of a device for communicating messages prepared for the calling subscriber by the called subscriber (not to be confused with the pick-up of a sound recording and reproducing device D for recording messages from the calling sub scriber which will be referred to later).

As soon as the pick-up Q has communicated the message prepared for the calling subscriber, switch m3 is again closed and switch m4 is opened after further rotation of the motor shaft. An electric siren S or like instrument for the generation of an alternating current of sound frequency now sends a signal to the calling subscriber. The end of this signal indicates the A, which is modulated by the speech of the callreadiness of the device for recording, which may take place. when switch m4 is closed and switch plifier W to the closing again of the switch mt m5 opened after further rotation of the motor shaft. In a like manner also the stateof preparation of the apparatus for recording and the end thereof may be indicated by other signals,

shunting the siren S is longer than the time reguired to heat up the valves of the amplifier.

Instead of using a siren, a microphone which transfers acoustic signals to the exchange line eBmay be shunted across the switch m4. Alternatively, anotherpick-up Q may be arranged as-or in addition to the siren S in parallel with the-switch 1nd, or with another switch which is controlled according to the number of revolutions of the motor M, which pick-up Q transmits a recorded message to the Exchange Omce line AB from a sound record prepared by the called subscriber.

The duration of the'signal emitted by the sirerror the like is detemiined by the time which must be allowed for the calling subscriber to decide upon the message he wishes to record for the absent called subscriber. This period also enables the amplifier valves to be heated up.

The switch me which is shunted across the siren S, may be opened temporarily during or just before the recording period in order to indiperiod, or the approaching beginning orend thereof.

Instead of, using an electric sirenhaving atoothed wheel, the blades of a fan or an exhaustuniform.

pending on the quality of J the loudness of the voice of ing subscriber passes via switch ml through switch a! to the input transformer IT'of the amplifier W and therefrom through switch a8 back to the exchange line wire B.

Instead of being applied through an input transformer IT to the amplifier W, a modulated.

alternating current may be applied directly to the grid of the amplifier input valve, after being diverted from the exchange line direct current circuit by means of an alternating current shunt. This result will be obtained if, for example, the direct current circuit is closed, when the switch m5 is opened, through a choke F, the alternating current resistance of which is so high that the modulated alternating current of sound frequency cannot pass therethrough, whereas its resistance to direct current is suited to the wiring of the telephone system. A condenser C, on the other hand, cuts ofi the direct current circuit from the amplifier.

The contact I) of the switch a! is new connected to the grid of the amplifier input valve. and the contact b of the switch 148 is connected to the negative line of the amplifier. The potentiometer-P enables the necessary grid potential to be obtained, and also permits adjustment of the amplifier so that the end stage thereof is protected against overloading. This adjustment must be made when the device is installed since the terminal energy of the altemating speech currents will be considerably different at diflerent points of the telephone system, even with energising sound energy.

But even at the same point of the telephone network the modulated alternating currents of sound frequency will be of different intensity dethe microphone, on the calling subscriber,

' and on the condition of the exchange lines at ing machine for removing shavings of the rec- ,ord ,ca'rrier produced by cutting the sound record of "the message may be employed. If the speed oi the exhausting machine is too high for practical purposes, some of its blades may be made from a non-magnetisable material and others from a temporarily magnetisable one.

The magnet of the siren may be an electromagnet which is energised by direct current from the exchange line. In this case a contact may be disposed immediately adjacent to each of the terminals of the electromagnet, which contacts are closed just before the switch m4 is opened,

and opened immediately after this switch is closed again. The capacity of these contacts should be as small as possiblein order to render theirresistance to alternating. currents so high the time. The potentiometer P must, in practice, be adjusted to an average value and the.

difierences of sound volume when recording must be compensated upon reproduction as far as possible by means of a sound volume regulator R (potentiometer) When the difierences in the intensity of the received alternating speech currents are very high, the amplifier may be equipped with automatic sound volume regulation (contrast compensation), as is well known in the telephone and radio art.

The conduction of the alternating speech currents to the grid of the input amplifier in the manner indicated above has many advantages over coupling by means of a transformer.

The amplified modulated alternating currents of sound frequency pass from the amplifier outlet 0 by switch all to an electromagnetic recording and reproducing device D and therefrom by switch all! back to the amplifier output. The

device D is adapted for recording the sound on a record carrier.

When the recording period is over, the control shaft rotated by the motor thereof has been turned sufilciently for the switch m2 in the exchange line circuit to be opened by cams or the position circuit for initiating the reproducing operation of the apparatus are not yet closed. At this moment the switches id, at, u! and all! may or may not be closed in the position for reproduction (1. e. the contacts b and c thereof engaged),

but if not closed inthis position they may be so closed by setting the control handle into its position for reproduction.

If now the calledsubscriber wishes to have any records reproduced, he sets the control handle into its position for reproduction, whereby the contacts b of the switches a1, a8, usand all! are connected to contacts thereof if this has not already been done in the intermediate position.

Gil

ture and switch 1 is closed, so that one of the wires to the exchange is connected to the earth wire E as long as the camrotated by the motor keeps the switch mia closed, which is during the entire recording period after s. predetermined number of revolutions of the motor.

The called subscriber's station thus gives the engaged signal to any further subscriber calling during this period. When the entire cycle The recording and reproducing device D is adjusted by the control handle to its picking-up and then sends weak sound frequency alternating currents through switch 11.1 to the amplifier inlet IT and thence through switch n8 back to the recording and reproducing device D.-

Aregulator, such as a potentiometer R, connected in parallel with the device D, permits regulation of the sound volume. From the amplifier output 0, the amplified modulated alternating currents of sound frequency pass via switchas to a telephone receiver ordoudspeaker T, and thence through switch all! back to the amplifier output.

By suitably constructing the recording and reproducing device D, it is possible to hear the modulated alternating currents produced thereby with a telephone receiver and without amplification. In this case the switches ul. ul, 119 and uiil are modified accordingly. us, for example, the contact 0 is omitted from the switches ul and u8. The contacts b of these switches are then closed by connection with contacts a for recording, and opened for reproduction. Inthe case of the switches a9 and ulil, the contact a is in' each case disposed as the middle ,one andthe contact b as the left one, i. e. the

two contacts are interchanged with one another.

The arrangement somewhat modified as shown by Fig. 21.

In this modified arrangement, a relay L is arranged in the line leading from'the exchange line A to the switches GI, m2, m3, ml and m5,

connected in series with respect to one another.

(Switch m5 may be dispensed with as 'will be explained hereinafter.) When switch GI has been closed by the centrifugal governor G (Fig. 1) and switch m2 by a cam or the like. the reas shown in Fig. 1 may be lay L is energised by the direct current com-y ing from the exchange line. The-armature of relay L then opens a switch 1 and thereby prevents the exchange lines from being connected, through a switch mid, to the earth wire'E.

The switch 1n2a is closed and opened concurrently with switch m2 by means of a cam. driven by theoperating motor M (Fig. l) for the general device.

Now when the calling subscriber does not wish to communicate any message to the called sub scriber and accordingly interrupts his connection with the latter, the relay L drops its armagovernor G so that it remains closed as long as the motor M maintains its normal speed, may

be included in series with the switches l and Another improvement in the arrangement shown in the circuit diagram of Fig. 21, as compared with the arrangements shown ,in Fig. 1, consists in that the pick-up Q for communicating messages prepared by the called subscriber to a calling subscriber and/or the signalling means (siren S or the like) are not simply shortcircuited by the switches mI-and rml respectively, but are shunted by pote'ntiometersP: and P4, respectively, whereby the sound intensity communicated by these auxiliary devices to the calling subscriber is regulable. v

A further modification consists in that the switch ms of the'arrangement shown in Fig. l is omitted in the arrangement shown in the diagram of Fig. 21. The exchange line circuit may also be coupled to the inlet circuit of the amplifier W by means of a transformer J, one terminal of which is connected to the frame of the amplifier and the other terminal to the contact a of switch ul. Contact b of this switch is connected as usual to' the amplifier inlet IT, the other terminal of which is connected to the frame of the amplifier.

Contact c of switch 11.1 is connected to one terminal of the recording and reproducing device D, the other terminal of which device is connected to contact b of switch at, contact c of which is connected to the frame of the amplifier W. Accordingly. when the switches ul and at are set to reproduction by means of the control handle, the recording and reproducing device Dis connected to the inlet IT of the amplifier As to the switches a9 and ulil, the contacts 11 thereof are connected as according to'Fig. 1 to the output 0 of the amplifier W, and the coni tacts care connected'to the telephone receiver, or loudspeaker T. The sound frequency modu lated currents produced by the device D when picking-up the recorded messages are amplified by the amplifier W and reproduced by the teleare, as described hereabove, transmitted over the transformer J and switch 1:1 to the amplifier} inlet IT. The device D is, as explained here-- nection with these switches.

(b) A recording medium and recording and 4 pick-up means therefor,

(c) A control shaft or shafts for autbmatically engaging and disengaging certain mechanical elements, and switching on and oil. certain circults during the cycle of operations corresponding to the "recording (I) and to the "reproducing" phase (III), respectively (d) Devices 'for counting the number of messages, and for positioning the recording stylus or other device and reproducing pick-up means to the appropriate place with respect to the recording medium, and switching ofi the apparatus after reproduction of the last record or when the capacity of the recording medium has been exhausted.

These mechanical arrangements will first be described with reference tothe recording" phase (I). Referring now to Fig. 6 a control shaft I is shown as being coupled by means of the general control handle U to a motor driven shaft 2 so as to make one revolution during one recording. On shaft I are provided severalcams only one of them, 3, being shown in the drawings (cam 3 serving for use during reproduction, will be described later). The cams not shown serve for the control of certain switches such as ml or m2 as will be described more fully in com- The cam 3 acts on a slidably or tiltably arranged member 5 which will be referred to shortly'as the slide 5. On the inner side of said slide are provided two wedge shaped faces 8 and i respectively each of which cooperates with a pair of scissors-like levers 8, 9, and II), II, respectively,

which are normally closed by the springs l2 and |3,respectively, so as to bring rollers |4, l5, and l6, l1, provided respectively at the ends of

levers

3, 9, and "I, ll, into engagement'with a roller length which-allowing for 7 a recording stylus 22 of the electioacoustic system (D. Fig. I).

The surface of the'roller 2| is acoustically insulated with respect to its axis layer of soundproof material. This rollermay be forced by a spring 23 against the stylus 22 of the electroacoustic system.

As in this embodiment the individual records are recorded in parallel tracks on a tape of finite fixture, and starting and stopping-is approximately equal to the 'average length of the individual message records,

the slide 5 to be shifted to and the reel roller is the recording medium must be wound back when the record is terminated in order to be ready for the recordingof the next record. This winding back is effected in the following way: after a predetermined number of revolutions of the driving motor (M, Fig. 1) corresponding for exampleactual recording, the

to the termination of the shaft I has been turned so far that cam 3 allows the left, so that the levers I, H are opened" by the wedge and the coupling between themotor driven roller l8 disengaged. Simulta neously the roller I3 is coupled by means of the rollers, I! to the reel roller |9 so that the record tape is wound back from the reel driven by roller 28 onto the reel driven by roller 1 9.

The levers 8, 9 are connected by means of a link '24 to a'lever 28 supporting the bearings of roller 2| which is thus 22 before the rollers i9 and the motor driven pulley l3. A knife edge may serve as a fulmust be effected I 8 driven by the motor (M, Fig.1) and either one of two rollers I9 and 20, connected respectively to two reels on which the recording medium is wound.

Depending upon the position of the slide 5, at least one pair of coupling rollers l4, l5, or l8, II

are disengaged by the action of the wedges 8 and I, respectively.

The slide 5 is biased by' a spring (not shown) to contact with the cam 3 during recording. Thiscam is so shaped that during its rotation, the slide 5 remains in its mid position, but as soon as the apparatus is ready for actual recording, the slide 8 is moved to the right (in'Fig. 6) so as to bring the wedge .1 out of engagement with the levers I8, I! which consequently are closed by the spring i3.

The rotation of the roller I8 is thus transmitted to the reel connected to the roller 20, whereby the tape recording medium is wound onto this reel from the reel driven by the roller I9 passing over a roller 2| whereon it is exposed to crum for the lever 28 and the roller 2| is moved against the bias of the spring 23. *Altematively,

the stylus 22 may be liftedaway from the roller 2| by means of the link 23'.

In addition to winding back the recording medium, .a transverse movement of the recording stylus 22 with respect to the recording medium prior to the next actual record-' ing,.in-order that the next record shall be made parallel to the foregoin'g one. This is effected by a device shown in Figs. 2 and 4. l

The shaft 28 of reel roller I9 is equipped with a toothed wheel v2'| toothed wheel 28 slidably mounted on a shaft 29 and is biased by a spring 30 to the left (Fig. 2). I The toothed wheel 28 is connected to an arm 3| supporting a pin wheel 33 which provides a step-by-step motion gear for lateral shifting of the stylus 22. For each revolution of the toothed wheel 28, the Geneva wheel 33 is rotated through'o'ne step, and between successive movements, it is fixed by engagement of a cylindrical member 34 carrying the arm 3| which cylindrical the concave portions of the Geneva wheel.

The ratio between the

gear wheels

21 and 28 is such that for each winding back of the recording medium on to the reel driven by roller ill, the Geneva wheel 33 is moved one step. (Instead of being driven from the shaft 28, the arm 3| may equally well be controlled directly from the control shaft I (Fig. 6) for example by means of cams, levers, toothed gears or the like).

by an intermediatewithdrawn from the stylus which meshes with another 32 for rotating a Geneva member'engages in one of 38. By means of a spring 31 a onto the reel driven winding back of the recording medium, the stylus 22 ofthe electroacoustic system is moved one step transversely or the recording medium so that this tape medium is covered successivelyby sound records recorded in parallel grooves.

In order to prevent the Geneva wheel 33 from being moved backward, whilst the recording medium is being wound back onto the reel driven by roller 23, i. e. during reverse rotation of the shaft 25, the spring 30 is provided to force the toothed wheel 23 and the arm 3| to the left so that the pin 32 is brought out of engagement with the Geneva wheel 33. On the other hand, in order to couple the Geneva wheel 33 to the member 34 during winding of the recording medium by roller I9, the member 34 is forced, against the action of spring 30, into engagement with the Geneva wheel 33 by means of a lever 42. This lever is controlled by a cam 43 which is connected to a toothed pinion 44 and is held in operative engagement with the lever 42 by means of a spring 45. The toothed pinion 44 meshes with a toothed rack 46 which is oscillated by the reciprocating movement of the slide 5 (Fig. 6).v Alternatively, the rack 46 may be controlled by a cam (not shown) on the control shaft I (Fig. 6).

Depending upon the position of the slide 5, the cam 43 is positioned so as to press the lever 42 against the member '34 as long as the reel driven by roller I9 is coupled with the motor driven roller l8, and is in a position so as to allow the lever 42 to come out of engagement when the reel driven by the roller is rotated.

In order to prevent the Geneva wheel 33 from being rotated unintentionally when the pin 32 on member 34 is out of engagement with it, the member 34 is provided with a lateral extension so as to form a complete cylinder which engages one o! the concave recesses of the Geneva wheel 33 during the entire rotation of the member 34.

Asdescribed hereabove the Geneva wheel 33 is coupled with a toothed wheel 38 by engagement of a lateral pin 40 into a hole by the action of a spring 31. This toothed wheel 33 meshes with another toothed wheel 41. As each step of the Geneva wheel correspondsto one winding back of the recording medium, such a step constitutes the unit of a metering or counting device formed by or connected to said toothed wheel 41.

The toothed wheel 41 is connected to a spring which is preferably arranged within said wheel, and is tensioned by the step-by-step motion of the Geneva wheel. As will be described more in detail in connection with the reproduction of the records, the force of this spring is used for mov- 'ing the electroacoustic-system backwardly transversely of the recording medium, the electrobeing connected .as described with the nut 4| onthe threaded spindle 36 which is coupled with the toothed wheel 38 meshing with the toothed wheel 41.

On a fixed shaft 43 for is rotatably mounted a disc 49 having laterally projecting

pins

50 and 5|. The projection 50 is engageable in a single hole provided in the lateral face of the toothed wheel 41, and the projection 5| is engageable in one of a series of holes 53 in the toothed wheel 41,

Geneva wheel 33 which.

is held against disc 4' a plate 52 (see also Fig. 3) which rotation in order to arrest rotation of the when coupled therewith.. This plate 52 is laterally slidable so that it can be brought out of range of the projection 5| tor a purpose which will be described more in detail in connection with the reproduction of the records. 7

The disc 43 isi'urthermore provided at its periphery with two radial extensions 54 and 55 transversely of the recording which may bear on projections 53 and 51, respectively, extending laterally from the toothed wheel 41 and the frame 53. As will be described in greater detail in connection with the reproduction of the records. the projection 51 serves as a fixed starting point for the movement of the recording and the reproducing pick-up means, medium, and the projection 54 serves as a movable starting point, in order that reproduction may be started from the commencement of the first record which has not already been reproduced, and continue recording from the end of the last record reproduced.

By means of a bell-crank lever n59 operated by the general control handle U, the disc 49 may be shifted axially in one direction so that the pin 50 projecting laterally therefrom may engage the hole in the toothed wheel 41 or in the other direction so that the pin 5| may engage one of the holes 53 in the plate 52. Each of the holes 53 in plate 52 corresponds to a longitudinal zone of the recording medium and between the last and the first holes (531) and 53a, Fig. 3) is a sector, to allow for the projections 54 and 55 of the disc 49 and the projections 55 of the toothed wheel 41, and disc 51 of the frame 58.

The ratio between the gears 38 and 41 is such that the hole in the toothed wheel 41 aligns with the last hole 53b in the plate 52 when the capacity of the recording medium has been exhausted.

The operation of the device is as follows: preparatory to recording, the operator by setting the general control handle U to its recording" position (I) moves the crank lever 1:53, to its right hand position so that its projection 5| engages one hole 53 in the plate 52, whereby the disc 49 is prevented from rotating.

In the case of a first record on a new recording medium, the projection 5| is engaged in the first hole 53a of the plate 52. In this position, the lateral projection 50 of the disc 49 is disengaged from the single hole in the toothed wheel 41. The peripheral projections 55 and 54 on the disc 49 bear respectively on the projections 51 of the fixed frame 53 and on the projection 55 on the toothed wheel 41. When the latter is caused to rotate by the toothed wheel 33, due to the movement of the Geneva wheel 33, the projection 55 on the toothed wheel 41 moves away from the projection 54 on the disc 49, which latter is fixed against rotation during this phase.

For each record the toothed wheel 41 is rotated As will be described in greater detail with reference to'the reproducing phase (III), the device is set to the-position corresponding to the first hole 53a in the disc 52 for reproduction of the first series of record. After reproduction of the last record of this series, it is again in the position where it was after recording of the last record.

when the device is again adjusted for recording, the disc 45 is again moved to the right until disc 49 through the bellthe lateral pin therein engages the hole the plate 52 corresponding to the number of records which have been already reproduced.

The new incoming calls cause furtherstep-bystep movement of the Geneva wheel 33, and ac-,

cordingly of the toothed wheel 41, the spring connected to which is further tensioned, and the projection 56 on which is again removed from contact with-the projection 54 on the disc 49, which disc is now in a position corresponding to the commencement of the unused space on corded on the recording medium, the movable starting point 64 is again displaced, and recording of a fresh series of records begins from the new position of the projection 54 until the record tape has been recorded on over its entire width, i. e. until its recording capacity is exhausted.

When this capacity is very large, so that the ratio of the gears 38 and 41 becomes abnormally high, the projection 56 may be provided on a planet wheel (not shown) instead of on the toothed wheel 41, whereby the ratio between the wheels 38 and 41 may be reduced to a practical value.

0n the other lateral face of the toothed wheel 41 a further projection 60 is provided which operates the switch 0'! (see also Fig. 1) when the toothed wheel 41 is rotated further by the operation caused by a new incoming call, after the last record for which there was a space available on the recording medium, has been recorded. This switch 01 is normally closed and is opened by the projection 60 so that all the circuits of the device which are connected to the public supply .mains N are interrupted and the device as a whole is rendered inoperative on further incoming calls.

When after one or a series of calls have been recorded, the subscriber wishes to attend permediate" position (11), they must be opened now by setting the control handle U to the reproducing-position (III), and at the same time the switches a3 and M must be closed. Switch 06 being normally closed, a current nowpasses from the public supply mains N through switch a3 to the amplifier W and through switch M to a thermal switch Z which closes switch zl and thereby starts the motor M after a time delay, corresponding to the time requiredfor heating the cathodes of the amplifier valves up to emission temperature.

The thermal switch Z and the switches zl and a l may be dispensed with when. amplifier valves are used which attain their emission temperature at once, or when an electroacoustic system is used with the pick-up D which produces audible modulated currents without requiring any amplification.

sonally to incoming calls (for example after having returned from an absence), the general control handle U must be set to its intermediate position (11). The switch ul is thereby set to be, the apparatus thus disconnected from the exchange lines AB and the subscriber's station Y connected to the exchange lines. By setting the general control handle U to the intermediate" position the condition of a number of other switches may or may not be altered to prepare them for subsequent reproduction. For-example,

the switches u6 and n2 may be opened already by setting the general control handle U to the "intermediate position because this has no infiuence on the operation of the apparatus in this phase. The switches a3 and uimust not, however, be closed. in this position of the general control.

If now the subscriber wishes to reproduce any of the records made during his absence, he sets the general control handle'U to the position for reproduction" (III), whereby the switches ul,

. a8, a9 and all are set to be, the reproducing pick-up D is connected to the input IT of the As will be more fully described with reference to Fig. 5, switch at is opened automatically as soon as the reproduction of the last record has been completed, and all circuits connected to the public supply mains N are thereby interrupted.

Referring now -to-Fig. 6, by setting the general control handle U to the reproduction position (III) the control shaft l is coupled to the shaft 6| which is also driven by the motor M, but preferably the ratio of gearing between the shaft l and the shaft 6| is different to that between shaft I and shaft 2. One revolution of the control shaft ,l corresponds'to the duration of one recording (I) or reproducing (III) operation and these durations are generally of difierent length for the following reasons:

Primarily, the current supplied from the public supply mains N to the amplifier W is generally an alternating current and 'an appreciable lag of time is thus required for heating up the cathodes of the valves to emission temperature. Generally the individual records are recorded. at comparatively long intervals so that the amplifier valves will require heating-up anew each time a call is made whereas the records will generally be reproduced one immediately after the other so that one heating-up of the Secondly, in most cases it will be necessary to inform the calling subscriber that his mes-- sages will be recorded, to allow him' time to formulate his message and finally to advise him lag of time is usefully employed. In reproducthat the apparatus is prepared for recording.

During the heating-up time of the amplifier valves, the signs, signals or .informations may be given to the calling subscriber, so that this tion such information and the like is not required. 1

Accordingly it is advisable to include the heating-up time of the'amplifier valves in the amplifier W and the receiver or loudspeaker T g is connected to the amplifier output 0. This setting of the contacts ul, a8, 1L9 and all) may alternatively be effected when the general control handle U is set to the intermediate position.

It the switches uli and a2 have not been opened "recording cycle for each call but not in the reproducing cycle. This can be achieved by starting the motor for recording while the amplifier is still being heated-up whereas for reproduction the motor is not started before'the amplifier valves have reached their emission temperature. Consequently the duration of reproducing is difierent from that of recording.

On the control shaft I is provided a second I 4 set of cams for reproduction of which the cam by setting ofthe control handle to the inter- 7 4 only has been represented in Fig. 6. This cam acts on the slide 5, in asimilar manner as described with reference to cam 3 for recording.

the duration of the two periods is made equal,

a single control shaft I may be used which is permanently coupled to the driving motor Also if the length of both operations happens to be the same, a single set of cams would suffice.

For the actual reproduction of each individual record, the reel driven by the roller It is coupled to the motor driven roller 18 by the coupling rollers l4 and I5, and for winding back the recording medium preparatory to the reproduction of the next record, the reel driven by the roller 20 is coupled to the roller it by means of the coupling rollers l6 and' I1, depending upon the difierent positions of the slide 5 which is controlled by the cam 4 exactly as described with reference to cam 3 for recording. There is, however, the general diiference that the apparatus is switched off after recording each individual call by opening switch ml (Fig. 1) in order to prepare the apparatus for receiving the next incoming call, whereas it is not necessary to switch oil the apparatus after reproduction of each individual call, so that after completion of one revolution the shaft l continues to rotate thereby automatically effecting. the reproduction of the next record. This can lie effected satisfactorily since suitable intervals are provided between the actual reproduction of successive records due to the rewinding of the recording medium, the length of which in this embodiment, as already mentioned, corresponds to that of each individual record. As will be described with reference to another embodiment where no intervals are provided between reproduction of successive records, due to the nature of the recording medium, reproduction (III) may be stopped automatically after the reproduction of each individual'record. This difference is, as will be understood, merely for convenience and is not essential forthe operation of the apparatus according to this invention.

As recording i made by mechanically engraving, in the embodiment now under consideration,

a needle 62 (see Fig. 6) 'is connected to the electro-acoustic system D for reproducing. By the general control handle U, this pick-up needle 62 is brought into operative position with respect to the recording medium instead of the stylus 22 when the apparatus is switched from the "recording" position (I) to the reproducing" position (III). The pressure of the spring 23 may also be reduced, but when the pick-up needle 62 is so arranged as to yield'in the direction of the pressure of the spring 23, this adjustment may be dispensed with. It will be understood that these settings may be effected by the setting-of the general control handle U to its intermediate position (11) Referring now again to Figs. 2 and4, the operation of the mechanism represented corresponds generally to that described in connection with the recording" (1). During each winding back of the recording medium preparatory to the reproduction of the subsequent record, the-Geneva wheel 33 is moved one step and the pick-up I means which is connected to the nut 4| on the threaded spindle 3C is moved transversely to the recording medium so as to be correctly positioned on the next succeeding parallel record. During The action of the cam 43 on the lever 42 can since it rotates under the lower end of the lever 42 whereby it is prevented from being raised by the spring 45. When the cam 43 has rotated clear of the lower end of lever 42 it i returned to its upper position by'the spring 45, and on further rotation, it rocks the lever 42 so that the apparatus proceeds to the reproduction of the next record. However, by again depressing thebutton 63, each record can be repeated as often as desired.

The step-wise motion of the Geneva wheel 33 which corresponds to the lateral movement of the pick-up from one record to the next, also rotates the wheel 41 which accordingly counts the individual reproductions in the same manner as it counts the individual recording.

Before reproduction can commence, the electro-acoustic device which is connected to the nut 4| .on the threaded spindle 33 must be positioned from the last recorded record to the first one the reproduction of which is desired. To this pu ose by setting the general control handle U to its intermediate position (II), the toothed wheel 38 is disengaged from the Geneva wheel by means of the bell-crank lever uil. Consequently the .spring connected to the toothed wheel 41 is retion 56 on the wheel 41 comes to rest against the projection 54 on the disc 43.

In order to ensure that the tension of the spring connected to the toothed wheel 41 is sufilcient to drive the pick-up back to its initial position opposite to the first record, it is advisable to impart a preliminary tension to this spring.

' which is mounted on shaft 23.and consequently the toothed wheel 41 is again moved stepwise by means of the gear 21, 23, the arm 3l, the Geneva wheel 33 and the toothed wheel 33, and this time the disc 4! iscoupled to the wheel 41 so asto be rotated therewith. The radial projection 33 on the periphery oi the disc 43 accordstarting point.

after reproduction of thefirst series'the apparar' tus is again set by the control handl U for recording (I). The lateral projection thereon thus-engages in the hole 53 in the plate 52 which corresponds to the-number of records in the first series. When after recording of a second series of records the general control handle U is set toits intermediate position (II), and the wheel 41 is released so as to rotate in the reverse direction under the influence of the spring connected thereto, the projection on the periphery of the disc 49 is in a position corresponding to the hole 53 engaged by the projection 5|, and the wheel 41 therefore does not rotate back to its initial position but only until the projection 56 abuts against the projection 54 on the disc 49. I

If the apparatus is again set to reproduction (III) by the general control handle U, reproduction starts from this new position of the stop 54 which is the movable starting point, and the automatic however, the further function of disconnecting the apparatus from the public supply must be performed automatically. In*previous arrangements, switching-oil is only effected of its endp'ositions i. e. either when its capacity hasbecome exhausted or when it hasbeen fully wound back. Incarrying out the invention,

either a single counting'mechanism may be arranged which for recording is moved one way and for reproduction is moved in the reverse direction, cutting out the apparatus as soon as j when the recording medium has reached one during recording," switching off the apparatus [as soon as it has reached the position reached first record of the new series is thus the first one tobereproduced.

These cycles are repeated on each occasion that a new series of records is made and reproduced. When finally the capacity of the reswitched off by means of the switch c'l, which is opened by an abutment 60 on the wheel 41 in a known manner, as described hereabove. In order to render the apparatus again operative, the recording medium must be exchanged and the apparatus must be reset to its initial position where the stylus 22 of the electroacoustic system is in alignment with'the zone on the fresh recording medium where the first message is to be recorded.

To this purpose, the shaft is released from the Geneva wheel 33 by withdrawing the pin of the wheel 38 therefrom, the projection on the disc 49 is disengaged from the hole in wheel 41,.and the plate 52 is shifted to the right so that the right hand pin 5| of the disc 49 does not engage any hole of this plate. All these movements are preferably caused by setting the awaiting reproduction;

by the first one.

Apart fromtheir function as automatic switching off means, these counting mechanisms may also serve to indicate visually to the subscriber the number of records not yet reproduced i. e. before reproduction of the last series of recorded records has been started the total number of this I series and during reproduction the numbe In Figs. 1 and 5 the electrical connections and the mechanical arrangement are shown of an embodiment of a counting mechanism moving in one direction for recording (I) and in the recording medium is exhausted the apparatus is i verse-direction for reproduction In the direct current circuit+-of the am} ducing" (III) by means of the general control handle U. To the contacts a, c, respectively of this switch electromagnets 65 and 56 respectively are connected,.which actuate oppositely toothed ratchet wheels 59 and 10 through pivoted levers rality of semicircular recesses 13 which are general control handle U,to a fourthposition which will be referred to hereinafter as the change position (IV.) v 2 Consequently the wheel 41' rotates in the reverse direction under the influence of its asso-- ciated spring, the projection 56 thereon carrying with it the projection 54 on the disc 49 until the projection on the latter bears against the abutment 51 on the fixed frame 58, i. e., against the fixed starting point.

The toothed wheel 41 serves as a counting mechanism or as a plurality of counting mechanisms whereby complete automatic functioning of the apparatus is obtained. The angular displacement of the latter bears against the abutment 51 ofthe fixed frame 58 (i. e.-the fixed starting point) indicates the total number of records recorded or reproduced or the total length of them, while the angular displacement of this projection 56 from the projection 54 on the disc 48 (i. e. the movable starting point) in- .dicates the number of length of-records recorded but not yet reproduced.

In order to render the apparatuscompletely equally spaced at the samepitch as the teeth of the

ratchet wheels

69 and 10. A springlatchl4 successively engages the recesses 13 of the wheel ll and thereby prevents unintentional rotation thereof. However, when either 'ofthe two. I Q

recess 15, and on the periphery of the wheel slides a curved feeler I6 of the switch 06. This switch is normally closed and is opened only when the feeler 15 engages in the recess 15.

when the apparatusis set for recording (I) I the switch 05 is shunted by switch 1L5 (Fig. 1).

This is necessary because thecam wheel I2 is so adjusted that in the position prior to the first recording, the feeler I6 is in the recess '15 and the switch 05 is accordingly open. For each step of the counting mechanism (i. e. when actually recording or reproducing one individual record) a switch mII arranged in the direct current circuit+', which may be controlled by an abutment 11 on the Geneva wheel driving member 28 (Fig.' 2) is temporarily closed. In the recording phase when switch is set to ob, by closing the switch 17111 the electromagnet 5.5