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Publication numberUS2068106 A
Publication typeGrant
Publication dateJan 19, 1937
Filing dateMay 13, 1933
Priority dateMay 13, 1933
Publication numberUS 2068106 A, US 2068106A, US-A-2068106, US2068106 A, US2068106A
InventorsHorn Milton V, Lovett Herman I, Roy Earnest H
Original AssigneeHorn Milton V, Lovett Herman I, Roy Earnest H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sound emitting apparatus
US 2068106 A
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Description  (OCR text may contain errors)

Jan; 19, 1937. V; HORN AL 2,068,106

SOUND EMITTING APPARATUS Original Filed May 13, 1933 m ri -j Puonm Rama; i'd16 5 LINE I Patented Jan. 19, 1937 UNITED STATES SOUND EMITTING APPARATUS Milton V. Horn, Earnest H. Roy, and Herman I. Lovett, Buffalo, N. Y.

Application May 13, 1933, Serial No. 670,932

' Renewed June 19, 1936 14 Claims.

This invention relates to certain new and useful improvements in sound emitting apparatus and more particularly to a combined radio receiving set and phonograph or like device from which recorded messages or the like may be produced.

One of its objects is to provide an apparatus of this character which is designed to automatically offer radio entertainment interspersed with recorded messages of general interest or of an advertising nature.

Another object of the invention is to provide a novel and efficient sound producing apparatus designed for installation in stores, public places, street cars, and other places and having simple, efiicient and positive means for controlling at predetermined time intervals the operation of the radio receiving set and the phonograph.

A further object is the provision of a combined radio receiving set and phonograph including means for efiecting the manual control of such sound producing devices at the will of the user. I

A still further object of the invention is to provide an apparatus of this character having means for visibly indicating to the listeners which of the two sound-producing devices is operating, and also to indicate whether the apparatus is working under manual or automatic control.

Other features of the invention reside in the construction and arrangement of parts hereinafter described and particularly pointed out in the appended claims.

In the accompanying drawing:-

Figure 1 is a front view of a cabinet embodying the apparatus constituting our invention.-

Figure 2 is a diagrammatic view of the apparatus embodying our invention.

Similar characters of reference indicate corresponding parts throughout the several views.

In its general organization, our apparatus which We have termed an autoradiograph, consists of a radio receiving set, an auxiliary sound producing unit preferably in the form to produce recorded messages and illustrated herein as an electrically operated phonograph, a loud speaker common to the radio set and the phonograph, means for automatically rendering either the radio set or the phonograph operative, and a time control mechanism for predetermining the playing of the phonograph and the switching on of the radio receiver to alternately ofier radio entertainment interspersed with recorded announcements for advertising or other purposes.

In carrying out our invention, theradio receiving set and phonograph are preferably housed in any appropriate cabinet I0, the radio receiver being of any suitable and well known construction and indicated generally by the numeral ll, while l2 indicates the tuning dial, l3 the tuning knob and M the volume control knob thereof. The phonograph may likewise be of any well known construction, I5 indicating the record-supporting turn table, It the motor for driving it and I! the tone arm equipped with a magnetic pick-up l8 shown diagrammatically in Figure 2. Common to both the radio receiver and the phonograph is a loud speaker unit It including a vacuum tube amplifier connected 15 with the tone arm of the phonograph to step-up or increase its tone volume. Instead of employing a phonograph, any other sound reproducing device may be used, such for example, as an apparatus for reproducing sound from film. If 20 desired, a clock 2| may be mounted on the front or control panel of the cabinet, such clock being employed for controlling, at predetermined time periods and through other instrumentalities, the

playing of the phonograph and the radio receivmg set.

The means for automatically rendering the! phonograph or the radio receiving set independently operative at predetermined time intervals, and thereby afiord radio entertainment interspersed with appropriateannouncements or advertising messages suitable to a given occasion or to the store or other place wherein the apparatus is installed, is preferably electrical, embodying generally a time controlled switch which, when closed at a pre-set time as when the phonograph is to play, establishes a circuit which not only breaks or cuts off the current supply to the radio receiver to silence it but which simultaneously closes the circuit of the phonograph and brings it into operation. After a predetermined lapse of time, governed bythe length or duration of the recorded message or announcement to be given, a switch controlled by the tone arm or like governing element of the phonograph is closed and functions through the medium of the other elements in the circuit to cut off the phonograph to silence it and at the same time reestablish and close the circuit to bring the radio receiver again into operation. Means are also provided for manually controlling the circuits, so that the phonograph can be played as long as desired or the radio receiving set can be played continuously. The phonograph may also include any suitable and well known means (not shown) for automatically effecting the repetition of one or more records. In its preferred construction the mechanisms and circuits for accomplishing these results are constructed and arranged as follows:

Referring now to the circuit diagram depicted in Figure 2, 22 indicates the line or power switch and 23, 24 the feed wires leading from the switch terminals for supplying the current used in the operation of the various instrumentalities included in the circuit. The letter A indicates generally the electric clock control unit which may be of any ordinary :and. well known construction; B indicates one or more relays which will be hereinafter referred to'as the master control relay and which; 'in" its normal deenergized position; maintains the controlling circuit of the radio receiver. closed,-so that it will operate, and the circuit of the phonograph open, sothat it will be inoperative" or silent, while when said relay is energized it acts to render the radio set inoperative or silent and the phonograph'operative; C indicates a second relay which will be hereinafter referred to as the cut off relay and which is incooperative relation with: or in'the circuit of the master control relay to act as a breaker therefor, as

wwhen automatically switching from the playing -of the phonograph tothe playing 'of the radio receiver; and D indicates a manually controlled switchywhich when in its normal or neutral position, places the circuits in'condition for the automatic control-of.- the phonograph and the radio receiver, and which when set in one or the other of two positions permits the playing as long as desired ofthe phonograph or the radio receiver.

The master controls-relay B, diametrically shown in Figure 2, comprises a coil 25 and two armature sections "26 and 27, the armature secwith companione-fixed contact members 32,33, M34 :and 1355 .while the companion armature sec- -.-tion-. Zhoarries :similarw-contact. members aiiL -ltl,

38 and 39 which are adapted to makeand =-ibreak-withr companion fixed 'contactmembers e40,- 4I-,-.42 and-43. .The cutoff-relay C includes a coil:25'- and an armature contact member 44 adaptedeto make. and break with a companion fixed contact -member 45. The manual controlled switchD consists of an operating-lever "-phonograph and the radio receiver, respectively,

the switch'element' l'l carrying contact members M9 and SKI-adapted to engage-corresponding com- "panion contacts Stand-'52, whilethe switch "element 48 hascontact members. '53 and- 5d 'adapted -to engage" companion: contacts ES-and :---;56; respectively. #When the switch lever 45 is inits pendant or'neutral position, the apparatus is in proper". positiomafor automatic operation,

while when'this leveris shiftedto the left it isiinposition-for manual control of thephonograph and whenshifted to the right is in position for manual control of the radio receiving .wset.

deenergizedcondition, the phonograph is silent andthe radio is playing. Thev control circuit established for playing. the radio-set may be independent and-isshown as-including the wires 51 and. 58 which.are connected at one end to a switch 60 employed for manually silencing the radio, when desired, and connected at their other ends to one of the tubes in the radio circuit to control the filament voltage supply, the wire 58 having interposed in series therewith the companion contacts 30 and 34 of the relay armature-section 26, such contacts constituting a switch for automatically controlling the on and off positions of the radio receiver. When the relay B is energized, the contacts 30 and 34 are broken and the voltage supply to the connected radio tube is cut off, causing .theufilament in the tube to gradually cool off and reduce the emission thereof and producing a fading or dying out of the radio signal. When said relay is deenergized the reverse effect takes place. Other contacts, namely, contacts 29 and 33, operated by this relay are made to establish a circuit for bringing the phonograph into play, as will presently appear.

The energization of the master control relay B which is responsible .for the closing of the motor circuit of the phonograph torender it operative, is automatically effected through the e,.ti-vely with the feed wire 24, the wire-'65 leading directly to such feed wire and the wire 66 being a common and connected to the coils E5 and 25 of the relays B and C, respectively. The master control relay contact member 29 is connected by a wire 61 with the feed wire 24 and the companion contact member 33 is connected by a wire 68 with one terminal of the motor It, the other terminal of .the motor being connected by a Wire 59 with the other feed wire 23 of the power line. Therefore, whenever contacts 29 and 33 are closed, the phonograph motor is operated and thephonograph is brought into play, and when said contacts are broken the motor circuit is opened. and the phonograph stops playing.

The disk 6| of the time control unit A predetermines the closing of the circuit to bring the phonograph into play and for this purpose has at its periphery a plurality of contacts H! which are spaced about the periphery of the disk according to the predetermined times when it is desired to operate the phonograph alternately with the radio receiver. contacts i0 is adapted to successively and intermittently make contact with a fixed contact H connected by a wire 12 jointly to the fixed relay contact 35 and to one end of the master relay coil 25, the other end of said coil being connected Each one of the disk.

by the wire 66, contacts 63, 64 and wire 65 to l the power line feed wire 23. The disk 6| which is also aconductor, is connected through its axis by a wire 13 with the other side of the power line through the medium of the normally closed contacts 49, 5! of the manually controlled switch D, said contact 5| being connected by a wire 14 with the feed wire 23. With the circuit of the relay B closed whenever a disk contact 10 engages the companion contact H, the armatures 26 and 21 of such relay are actuated to close and open certain of its controlling contacts, among others closing the contacts 29 and 33 which governthe phonograph motor l6.

The duration of contact of the time-controlled switch "l9, H is only momentary, it being a wip- .operation is deenergized, are connected by wires and 16, respectively, to the power feed wire 23' and the master control relay contact 3!,

whereby the circuit is maintained closed across the contacts 3!, and 44, 45, after the clock control switch 10, H is opened or broken. The

completed circuit thus established to in effect I keep the phonograph motor circuit closed is through feed wire 23, wire 15, relay contacts 44, 45, wire 76, the master control relay contacts SI, 35 and its coil 25, and thence through wire 66, contacts 63, 64 and wire to the other feed wire 24, such circuit remaining closed until the phonograph through the medium of the switch controlled by it causes said circuit to be opened to render the phonograph inoperative and the radio receiver again operative.

This phonograph-controlled switch is included in the circuit of the cut off relay C and may be of any suitable construction, it being diagrammatically shown. in the drawing as consisting of a switch member T! carried by and movable with the tone arm H and a series of suitably spaced,

companion fixed switch members 18 which are disposed in the moving path of the switch memher 1! and which may be adjustably set as desiredin accordance with the playing time of a given message on the record, a single record having a series of independent messages thereon. The movable switch member 11 is connected by a wire 19 with the wire 15 leading to the feed wire 23, ,while the fixed switch members '18 are severally connected to a wire leading to one end of the coil 25 of the relay C, the other end of this coil being connected to the wire 66 in common circuit with the master control relay coil 25 and leading to the other side of the power line, thus completing the circuit of the relay C to maintain relay B energized and the phonograph playing. When the switch member H contacts with one or another of the companion members it, relay C becomes energized, breaking the contacts 4t, 45 thereof to likewise break the previously established circuit of the relay B, and deenergizing the latter to restore it to its original position, wherein the phonograph motor-governing contacts 29, 33 are broken to automatically render the phonograph inoperative and the radio-governing contacts 30, 34 are again closed to automatically bring the radio receiver into operation.

Should the electric clock control unit A cease to function for any reason while the phonograph is playing, we provide means in the con trolling circuit for maintaining the master control relay B energized and consequently the circuit of the phonograph motor it closed. For this purpose, wires 8| and 82 are connected at one end to the wires 65, 66 leading to the switch contacts 63, 64 of the clock-setting dials 62 while their opposite ends are connected, respectively, tothe contact member 36 carried by the armature 21 of the. master control relay and to the companion contact member 40, whereby the circuit of the master control relay is maintained closed across the contacts 36 and 40 should the clock control unit become incapacitated, it being understood that said contacts are closed whenever the master control relay is energized.

By the provision of the manually-controlled switch D, it is possible for the operator to selectively and independently set the apparatus to play the phonograph continuously or the radio receiving set continuously. When it is desired to play the phonograph continuously, the manualcontrolled switch lever 46 is turned to the left for the purpose of maintaining the master control relay energized through the switch contacts 54 and 56 rather than through the circuit controlled by the time clock and relay C, thereby dispensing with the time-controlled, automatic operation of switching the radio and phonograph alternately on and off. In the circuit thus established to eifect continuous playing of the phonograph, it being understood that the phonograph can come into operation initial ly only when the time control contacts If! and H are closed firstly, to energize the relay B and secondly, to close the phonograph motor control contacts 29, 33 by such energization of that relay, the path of the current is through wires 2s, 65, dial-setting contacts 83, 64, wire 66, coil 25 of the master control relay B, wire 12, then to a branch wire 83 joined at one end to said wire 12 and at its other end to the manual switch contact 56, thence from contact member 56 to the companion contact member 54, through wire 84 to the contact member 31 on the armature 21 of the relay B to companion contact member 4 and through a wire 85 connected at one end thereto and at its other end to the wire 89 leading to the feed wire 23. Thus, as long as the switch lever 46 is in phonograph playing posi- 1 tion, the phonograph will continue to play uninterruptedly.

When it is desired to play the radio receiving set continuously, the switch lever it is turned to the right which breaks the circuit of the time clock at the switch-contacts 49, 5!, thereby pre venting the master control relay B being energized and maintaining the radio set on across the normal closed contacts 30, 36 of the master control relay. Upon returning the switch lever.

to its neutral or automatic playing position, the time clock unit again is permitted to function to automatically and periodically control the alternate playing of the radio set and the phonograph.

It will be noted that in the manual operation of this apparatus the time control unit is in no way disturbed or interfered with, and when the switch lever 66 is set at neutral, the automatic time control instrumentalities again come into operation.

For the purpose of indicating whether the apparatus is operating under manual or automatic control or whether the radio set or phonograph is playing, we provide suitable signal or tell tale elements in the operating circuit. Such signals may be in the form of different colored lamps 86, 81 and 88 mounted on the control panel of the cabinet Ill where they may be readily seen. These lamps are connected at one terminal by a common wire 89 with the feed wire 24 and by separate wires 90, 9| and 92, respectively, with the respective switch contacts for opening and closing their circuits in accordance With the manual or automatic playing of the sound producing elements. The automatic indicating lamp 86 has its other terminal connected by the wire 90 with the contact 53 of the manually-controlled switch 53, 55, the latter contacts being also included in the circuit of the companion set of contacts 50, 54 controlled by the manual switch D, so that when the switch lever 46 is set at neutral, said contacts are closed and the lamp 86 is lit. The lamp 8'! is the radio-indicating playing lamp and its wire 9| is connected to one of the switch contacts 38, 42 controlled by the master control relay B, the companion contact 42 being connected to the Wire 85 which leads to the feed wire 23. The lamp 98 is the phonograph-indicating playing lamp and has its wire 92 connected to the contact 35 of the master control, relay actuated switch 3|, 35, the contact 3| being connected by wire '16, contacts 44, 45 of the relay C and wire 15 with the feed wire 23. Thus, Whenever the switch lever 46 is in its neutral position, the apparatus is playing automatically and the lamp 86 is lit constantly through the closing of its circuit at contacts 53, 55 and 56, 54; when the master control relay '3 is energized through the closing of the time controlled switch 16, 1| and thereafter maintained energized through the contacts 44, 45 of the relay. 0., the lamp 88 is also lit, indicating jointly with the lamp 86 that the phonograph is playing automatically; when the phonograph is cut off by the closing of the contacts H, 18 and the opening of the relay contacts 44, 45, the circuit of said lamp 86 is opened and it goes out, while the radio indicating lamp 81 is lit through the closing of its switch contacts 36, 42, the latter having been closed by reason of the master control relay having been deenergized by the breaking of the cut off relay contacts 44, 45. When the lever 46 of the manual switch D is shifted to effect the selective manual-controlled playing of the apparatus, the automatic-indicating lamp 86 goes out, its circuit being broken at 53, 55 or at 50, 54, and the lamp 81 or 68 is accordingly lit depending on whether said switch is set for the radio or the phonograph, it being understood that the radio indicator lamp 8'! will light whenever the contacts 38, 42 are closed as when the relay B is deenergized, and that the phonograph indicator lamp 68 will light whenever the contacts 3!, 35 are closed, as when said relay is energized.

Included in the circuit of the amplifier 20, which is operatively connected to the tone arm, are the switch contacts 28, 32 controlled by the armature 26 of the master relay B and connected by the wires 93, and 94, respectively, with the amplifier tube. When the master relay is energized to play the phonograph, the contacts 26, 32 are broken and the amplifier tube is thereby properly biased to cause the sounds emitted from the phonograph to be amplified; when said relay is de-energized to play the radio, the contacts 28, 32 are closed and the amplifier tube is thereby improperly biased with the result that the amplifier does not properly operate, the loud speaker of the radio receiver producing the tone quality desired.

In order to prevent the radio receiver being manually brought into operation while the phonograph is automatically operating through the master relay circuit established by the normally closed manual switch contacts 49, 5|, and

time clock contacts 16, 1|, and thereby eliminating any interference with the timing and normal automatic operation of the apparatus, we provide an auxiliary circuit for maintaining the master relay B energized even though its previously established circuit has been broken as when the manual switch lever 46 is moved to radio play position and said contacts 49, 5| controlled thereby are broken. To this end, the contacts 39, 43 controlled by the armature section 21 of the master relay are provided for establishing and maintaining the phonograph circuit operative even though the manual switch lever has been shifted to radio play position. The contact 39 is connected by a wire 95 with the wire 69 leading to the feed wire.23 and the companion contact 43 is connected by a wire 96 with the wire 13 included in the circuit of the time clock switch contacts 10, H, so that whenever the master relay B is energized by said time clock switch to automatically play the phonograph, the contacts 39 and 43 are closed and a branch circuit is established which retains the relay energized even should the switch lever 46 be moved to a position to break the normal circuit at 49, 5|. However, when the predetermined playing time of the record has elapsed, the phonograph will stop playing and the radio receiver will thenceforth play continuously until the switch lever has been moved to its neutral automatic playing position or to radio playing position, at which times the phonograph and radio receiver will alternately and automatically come into operation or the radio receiver will continuously play, respectively.

We claim as our invention:

1. In an apparatus of the character described, the combination of a radio receiving unit, an auxiliary sound-reproducing unit, a time-control mechanism for governing the playing interval between said units, respectively, and means controlled by said sound-reproducing unit in correlation with said time-control mechanism for controlling the duration of operation of such um't.

2. In an apparatus of the character described,

the combination of a radio receiving unit, an

said last-named means being correlative with said time-controlled means to simultaneously render said radio unit operative.

4. In an apparatus of the character described, the combination of a radio receiving unit, an auxiliary sound reproducing unit, automatic means for periodically and alternately rendering one of said units inoperative and the other operative, means controlled by said auxiliary sound unit for periodically rendering it inoperative and the radio unit operative, and manu- :rendering said units operative, means governed by said manually-controlled means for rendering said automatic means inactive whenever said manual means is rendered active, and means for temporarily rendering the manually-controlled means inefiective to selectively play the radio receiver when the auxiliary sound unit is under automatic rendition and eifective to play the radio receiver when the time period of the automatic rendition of the auxiliary sound unit has terminated.

6. In an apparatus of the character described, the combination of a radio receiving unit, a phonograph unit having a motor for operating it and a tone arm, automatic means for periodically and alternately rendering one of said units inoperative and the other operative, and means controlled by the phonograph unit for periodically rendering it inoperative and the radio unit operative and comprising an electric circuit including a switch, a time control unit in said circuit for closing said switch at predetermined intervals to render the phonograph operative, and switch means in said circuit controlled by the phonograph tone arm for periodically breaking said circuit to render the phonograph inoperative, said switch means including a plurality of spaced contacts within the playing range of the phonograph record.

7. In an apparatus of the character described, the combination of a radio receiving unit, an auxiliary sound reproducing unit, automatic time-controlled means for periodically and a1- ternately rendering one of said units inoperative and the other operative, means controlled by said auxiliary sound unit for periodically rendering it inoperative and the radiounitoperative, and visible means for indicating to the listener which one of the two units is in operation.

8. In an apparatus of the character described, the combination of a radio receiving unit, an auxiliary sound reproducing unit, automatic means for periodically and alternately rendering one of said units inoperative and the other operative, manually-controlled means for selectively rendering said units operative, means governed by said manually-controlled means for rendering said automatic means inactive whenever said manual means is rendered active, and visible means for indicating to the listener which one of the two units is operative and whether the unit is operating under manual or automatic control.

9. In an apparatus of the character described, the combination of a phonograph having a motor for driving it and a tone arm, an electric circuit including a switch, a time-control unit in said circuit for closing said switch at predetermined intervals to render the phonograph operative, a master relay in the circuit of said time-control unit and said switch for closing the latter when energized to render the phonograph operative, a second relay in said circuit and including switch-contacts in circuit with said master relay to normally maintain the same energized, said second relay being normally deenergized, and switch means in the circuit of said second relay controlled by the tone arm for periodically closing the circuit of the second relayto break its switch-contacts and de-energize the master relay to open the first-named switch and render the phonograph inoperative.

10. In an apparatus of the character described, the combination of a radio receiving unit including ,a controlling switch, an auxiliary sound reproducin'gunit including a motor for actuating it and a switch for controlling the motor, an

electric circuit including said switches, an electric time-control unit in said circuit, a master relay for closing and opening said motor-switch d i'or opening and closing said radiocontrolling switch when said relay is energized and deenergized, respectively, a switch actuated by said time-control unit and governing the energization of said relay at predetermined times to close the motor-switch to render the auxiliary sound unit operative and to open the radio-switch to render the radio receiver inoperative, and a second switch controlled by said auxiliary sound unit for governing the de-energization of said relay at predetermined intervals to open the motor-controlling switch to render said sound unit inoperative and to close the radio-controlling switch to render the radio receiver operative.

11. In an apparatus of the character described,

the combination of a radio receiving unit including a controlling switch, an auxiliary sound reproducing unit including a motor for actuating it and a switch for controlling the motor, an electric circuit including said switches, an electric time-control unit in said circuit, a master relay for closing and opening said motor-switch and for opening and closing said radio-controlling switch when said relay is energized and de-energized, respectively, a switch actuated by said time-control unit and governing the energization of said relay at predetermined times to close the motor-switch to render the auxiliary sound unit operative and to open the radioswitch to render the radio receiver inoperative, a second relay included in the circuit of said master relay for maintaining the latter energized after the time-control actuated switch is opened, and a second switch controlled by said auxiliary sound unit and included in the circuit of said second relay for controlling the same, said second switch when closed energizing the second relay and breaking the circuit of and de-energizing the master relay to open the motor-controlling switch to render said sound unit inoperative and to close the radio-controlling switch to render the radio receiver operative.

12. In an apparatus of the character described, the combination of a radio receiving unit including a radio frequency tube, an auxiliary sound reproducing unit, automatic means for periodically rendering the radio unit operative and the auxiliary sound unit operative, means controlled by said auxiliary sound unit for periodically rendering it inoperative and the radio unit operative, an electric circuit including the aforesaid means, and switch means in said circuit controlling the filament voltage supply of said radio frequency tube and automatically controlling the on and ofi position of the radio unit, said switch means, when opened, cutting oii the voltage supply to said tube and causing its filament to gradually cool and reduce the emission thereof to produce a fading out of the radio signal, and to eflect a reversal of such filament action when the switch means is closed.

13.- In an apparatus of the character described, the combination of a sound producing unit including a vacuum tube amplifier, an

i electric circuit including said amplifier and a vacuum tube thereof, and switch means in said circuit controlling the filament voltage supply of said vacuum tube and automatically controlling'the on and ofi position of the sound producing unit, said switch means, when opened,

cutting off the voltage supply to said tube and causing its filament to gradually cool and. reduce the emissionthereof -to produce a fading out of the soundemitted from said producing unit, and to effect a reversal of such filament action when the switch means is closed.

14. In an. apparatusv of t the, character described, the combination of a. sound producing unit including electric power meansfor operating it, an electriccir'cuit including said power means,

MILTON V. HORN. EARNEST H. ROY. HERMAN I. LOVETT.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2561602 *Jul 29, 1947Jul 24, 1951Robert FineApparatus for making aural announcements
US2615993 *Sep 26, 1950Oct 28, 1952Melvin A CarterElectronically operated advertising and sound reproducing apparatus
US2704308 *May 14, 1952Mar 15, 1955Stromberg Carlson CoHowler circuit for telephone systems
US2883477 *Jan 21, 1953Apr 21, 1959Geissl FranzTransmitting devices for sound reproducers
US3825947 *Feb 16, 1973Jul 23, 1974Davis MMethod and means for giving point of sale commercial announcements
US4002858 *Dec 19, 1974Jan 11, 1977Giese Edwin GAudio program switching apparatus
Classifications
U.S. Classification369/2, 369/6, 455/231, 369/19, 369/69
International ClassificationH04B1/20
Cooperative ClassificationH04B1/20
European ClassificationH04B1/20