US1823717A - Telephone recording system - Google Patents

Telephone recording system Download PDF

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Publication number
US1823717A
US1823717A US124232A US12423226A US1823717A US 1823717 A US1823717 A US 1823717A US 124232 A US124232 A US 124232A US 12423226 A US12423226 A US 12423226A US 1823717 A US1823717 A US 1823717A
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US
United States
Prior art keywords
wire
recording
telephone line
currents
telephone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US124232A
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English (en)
Inventor
Howard S Worrell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dictaphone Corp
Original Assignee
Dictaphone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE343779D priority Critical patent/BE343779A/xx
Application filed by Dictaphone Corp filed Critical Dictaphone Corp
Priority to US124232A priority patent/US1823717A/en
Priority to FR637861D priority patent/FR637861A/fr
Priority to GB19171/27A priority patent/GB274872A/en
Application granted granted Critical
Publication of US1823717A publication Critical patent/US1823717A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/64—Automatic arrangements for answering calls; Automatic arrangements for recording messages for absent subscribers; Arrangements for recording conversations
    • H04M1/65—Recording arrangements for recording a message from the calling party

Definitions

  • This invention relates to amplifying and recording telephonically transmitted sounds.
  • An object of this invention is to provide for. amplifying and recording sounds transmitted over a. telephonic circuit ataudiofrequencies, and yet avoid detrimental effects to the transmission.
  • Another object is to provide for controlling the apparatus used to amplify and record sounds, so that it will be practically fool-proof, and will require practically no attention on the part of the user.
  • a further object is to provide a selfcontained and unitary apparatus for amplifying telephonic sounds and recording such sounds upon a phonograph record which may be employed subsequently to repeat the sound received.
  • a still further object is to provide as a single portable unit an amplifying apparatus utilizing vacuum tubes, a source of plate voltage supply, a source of filament heating current, and a source of grid bias, if the latter is used, recording and reproducing means, a supply of phonographic records, and a stand for supporting the above devices.
  • FIG. 1 is a diagrammatic view showing the parts of the amplifying and controlling apparatus and their connections to each other, and the recording mechanism' with its connections to the amplifying and controlling apparatus; also the connections from the telephone line to the amplifying apparatus and recording mechanism respectively.
  • Fig. 2 is a side view showing the cabinet for containing the coupling, receiving and amplifying means, and the cabinet for the phonographic recording means.
  • Fig. 3 is a perspective view of the device in accordance with this invention, showing the supporting stand, etc.
  • the present invention provides a coupling device between the tele phone line and the phonographic recording device, which coupling device positively prevents direct-current in the telephone line from passing through the coupler and yet permits voice or pulsating currents in the telephone line to pass through the coupler, where they are then induced in a receiving circuit, amplified and recorded on a phonograph.
  • voice currents of increased E. M. F. and an isolating condenser in series with the auto-transformer for permitting the voice currents to flow through the auto-transformer but preventing the direct-currents of the telephone line from passing through the auto-transformer, and'preventing lower frequency or magneto-currents from passing through in any appreciable amount, and also preventing any direct-current in the receiving circuit from being fed back to the telephone line.
  • the apparatus in its preferred form is mounted and supported in a cabinet 10, so as to form a complete unit with the exception of. the filament heating batteries and the plate voltage batteries.
  • wires 11 tapped from the telephone line 100 are attached to terminals 12 and 13 mounted on the cabinet 10.
  • a wire 14 leads to an isolating condenser 15, then to a wire 16 connected to an auto-transformer 17 which is connected by a wire 18 to the terminal 13 for the other wire 11.
  • a complete cir- Connected to the wire 16 of the auto-transformer 17 is a wire 19 leading through a switch S, hereinafter described, to a terminal 20 connected to the negative side of a filament heating battery 21 diagrammatically illustrated in Fig. 1.
  • the Wire 19 is also connected to a wire 22 leading to the filament 23 of a vacuum tube 24, While the other end of the filament 23 is connected by a wire 25 through a resistance 26 to a terminal 27 connected to the positive side of thefilament heating battery,21.
  • a Wire 28 leads from the upper end of the autotransformer to the grid 29 of the vacuum tube 24, the grid being provided with a leak 30 and a wire 31 leading to a C or biasing battery 32.. whose positive side is connected by a wire 33 to the wire 19 leading to the negative side of the filament heating battery.
  • the voice currents entering the coupler clrcuit and passing through the auto-transformer 17, induce voice currents of increased voltage in the output circuit comprising the auto-transformer 17, Wire 28, grid 29 of tube 24, filament 23, wire 22, wire 19 and wire 16, leading back to the auto-transformer.
  • These voice currents have the same characteristics as the voice currents in the input circuits and telephone lines except that they are of increased E. M. F.
  • the greater portion of these amplified voice currents cannot flow through the said output circuit comprising the wire 28 and grid 29, because of the high resistance of the grid circuit.
  • the voice currents which pass through the output circuit of the auto-transformer 17, are sufiicient, when picked-up and amplified by the vacuum tube 24 and one stage of audio-frequency amplification which will herelnafter be described, to satisfactorily operate an electrical recording unit 133 mounted 1n the carraige 134 of a phonograph to operate upon a record 135 and record therecrll signals received from the telephone line
  • the plate 36 of the vacuum tube 24 is connected to the primary 37 of an audio-frequency transformer 38 whose other wire 39 is connected with a terminal 40 which in turn is connected to the positive side of a plate battery 41 diagrammatically indicated in Fig. 1, the negative side of the plate battery being connected to a terminal 27 leading back to the filament at the same point that the positive side of the filament heating battery is connected.
  • the secondary 42 which is connected according to common practice by a wire 43 to a grid 44 of a vacuum tube 45 and by a wire 46 with a biasing battery 32, which is connected by a wire 33 to the negative side of the filament heating battery 21.
  • the filament 47 of the vacuum tube 45 is connected to positive and negative wires 25 and 19 respectively by wires 48 and 49 respectively, and the plate 50 of the vacuum tube 45 is connected by a wire 51 to a terminal 52 to which one wire 53 of the electrical recording unit 133 may be attached, while the other wire 54 of the electrical recording unit 133 ma be connected to a terminal 55 on the ca inet 10.
  • the terminal 55 is connected by a wire 56 to the wire 39 leading to the terminal 40 which is connected to the positive side of the plate battery.
  • the voice currents which are induced in the auto-transformer 17 and which pass through the output circuit consisting of the wire 28, grid 29, filament 23, and wires 22, 19 and 16 are picked-up and amplified by the vacuum tube 24, and further amplified by the vacuum tube 45 from which they are impressed upon the wires 53 and 54 leading to the electrical recording unit. This is done without making any direct-current connection to the telephone line 11 and without danger of high frequency currents feeding back to the telephone.
  • the system does not contain any oscillating circuits
  • the auto-transformer 17 and the condenser 15 being in series, and, ofcourse, being so arranged are incapable of setting up oscillation.
  • the motor 57 of the phonograph and the filament heating batteries are simultaneously controlled. This is done by connecting the leads 58 and 59 from the motor and its source of supply 60 to terminals 61 and 62 respectively on the cabinet 10.
  • the terminal 61 is connected by a wire 63 to' a pole 64 of a switch S while the knife 65 of the switch S is connected by a wire 66 to the terminal 62.
  • the switch S also contains a knife 67 connected to the wire 19 leading to the filaments of the vacuum tubes, and is adapted to cooperate with the pole 68 connected by a wire-69 to the terminal 20 connected to ,the negative side of the filament heating battery 21.
  • the knives 65 and 67 are connected together by an insulating denser 15, it is not necessary'or even desirable to provide a switch for breaking the telephone circuit connections to the device as was considered necessary in some of the early developments of this invention.
  • a cabinet 10 which contains the apparatus above described, is preferably mounted on a stand 72 comprising legs 73 having rollers 74 by means of which the stand may be moved from place to place as desired.
  • the cabinet 10 is identical with the cabinet 75 of the phonograph, the top portion of which is hinged at 76, the table 77 of the phonograph upon which the carriage 34, record 35 are mounted.
  • the cabinet 75 of the phonograph is mounted directly above the cabinet 10 of the receiving and amplifying means as shown in Figs. 2 and 3, and to give free access to the apparatus in the cabinet 10, the cabinets 10 and 75 are hinged together at 78 so that the cabinet 75 may be swung to position shown in Fig. 2 where it may be supported by a strut 79.
  • the stand 72 is adapted to support containers 80 and 81 for the filament heating and plate voltage batteries. These containers comprise bases 82 secured to the legs 73 and further supported by brackets 83 connected to the legs.
  • the stand 72 is. also adapted to support on a shelf 84 a rack 85 for holding a sufiicient supply of phonographcylinders carried by containers 86.
  • the rack 85 may be rotated to bring a cylinder into position where it may be removed. But, in order that the device may be kept as low as possible, sufficient clearance has not been left between the top of the containers 86 and-the stand 72 to permit the removal of a record and container. Therefore, the supporting shelf for the rack 85 is offset forwardly so that a portion of the rack projects beyond the front of the stand 72, and the cylinder and carton which is located in that position may be, therefore, readily removed without danger of coming into contact with the stand.
  • wires 11 are connected to wires of the telephone line 100, and also to the terminals 12 and 13 of the coupling, receiving, amplifying and recording device above described.
  • the said device being supplied with the proper batteries, the phonograph motor being supplied with a suitable source of current, and a phonograph record being in position to be recorded, let it be assumed that the telephone bell connected to the lines put circuit to the auto-transformer.
  • the station at which the receiving and recording device is located desires to use the telephone, the'person at the 1 instrument raises the r DCver from the hook the calling and called stations, and both sides of the conversation are, of course, recorded, because the line 100 is the interconnecting line between the two stations and is not merely tapped in at one station.
  • the finger-piece 71 is returned to switch-opening position and the conversation is either continued without recording it or is concluded according to the circumstances.
  • the opening and closing of the switch S which brings the receiving and recording mechanism into and out of operation has no effect upon the telephone line 100, and is not even perceptible.
  • battery eliminators may be used in lace of batteries 21, 32 and 41 if desired, an in such cases the eliminators may be supported in the containers 80 and 81 in the same manner that the batteries 21 and 41 are now mounted. It is merely important that some source of current for heating the filament of the vacuum tube and for supplying voltage for the plate circuits be provided.
  • An electrical system comprising a commercial telephone line; a coupler connected across said telephone line having in series with it a condenser to permit voice-currents to pass through the coupler but preventing passage of direct and signal operating currents either to or from the telephone line; an output circuit for the coupler; a thermionic device in the output circuit; and an electrically operated phonographic recording device controlled by said thermionic device, said coupler being continuously in circuit with the telephone line, and the output circuit of said coupler being normally open when the system is not in use; and means for rendering said thermionic device operative and thereby electrically completing the output circuit of the coupler.
  • a device for receiving and recording telephonic sounds and conversations, and adapted to be tapped across a commercial telephone line, comprising electrically operated phonographic recording means; thermionic amplifying means for amplifying voice currents to be impressed upon said recording means; a coupler between said thermionic amplifying means and the telephone line comprising means forming a complete electrical circuit across the telephone line for the passage of voice currents on the input side, and a thermionic device on the output side connected to the first mentioned thermionic device; control means for the phonographic recording means whereby the latter may be rendered operative to record sound; a source of current for the filaments of the said thermionic devices; and means for concurrently operating said control means to render the phonographic recording means operative and connecting the thermionic devices to the source of current for the filaments of thermionic devices, the last-named means being ineffective upon the input circuit of said coupler which is at all times electrically completed for the passage of voice currents therethrough.
  • a coupler connected across said telephone line having in series with it a condenser to permit voice-currents to pass through the coupler but preventing passage of direct and signal operating currents either to or from the telephone line; an output circuit for the coupler; a thermionic device in the output circuit; and an coupler.
  • 5/A device for receiving and recording telephonic sounds and conversations, an adapted to be tapped across a commercial telephone line, comprising electrically operated phonographic recording means; thermionic amphfying means for amplifyin voice-currents to be impressed upon sai recording means; a coupler between said thermionic amplifying means and the telephone line comprising means forming a complete electrical circuit across the telephone line for.
  • control means for the phonographic recording means whereby the latter may be rendered operative to record sound; a source of current for the filament of the said thermionic device; and means for concurrently operating said control means to render the phonographic recording means operative and connecting the thermionic device to the source of current for the filament thereof, the last named means being ineffective upon the in ut circuit of said coupler, which is at a times electrically completed for the passage of voice-currents therethrough.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Set Structure (AREA)
  • Devices For Supply Of Signal Current (AREA)
US124232A 1926-07-22 1926-07-22 Telephone recording system Expired - Lifetime US1823717A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE343779D BE343779A (enrdf_load_stackoverflow) 1926-07-22
US124232A US1823717A (en) 1926-07-22 1926-07-22 Telephone recording system
FR637861D FR637861A (fr) 1926-07-22 1927-07-18 Dispositif pour l'amplification et l'enregistrement des sons transmis par téléphone
GB19171/27A GB274872A (en) 1926-07-22 1927-07-19 Improvements relating to amplifying and recording telephonically transmitted sounds

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US124232A US1823717A (en) 1926-07-22 1926-07-22 Telephone recording system

Publications (1)

Publication Number Publication Date
US1823717A true US1823717A (en) 1931-09-15

Family

ID=22413599

Family Applications (1)

Application Number Title Priority Date Filing Date
US124232A Expired - Lifetime US1823717A (en) 1926-07-22 1926-07-22 Telephone recording system

Country Status (4)

Country Link
US (1) US1823717A (enrdf_load_stackoverflow)
BE (1) BE343779A (enrdf_load_stackoverflow)
FR (1) FR637861A (enrdf_load_stackoverflow)
GB (1) GB274872A (enrdf_load_stackoverflow)

Also Published As

Publication number Publication date
FR637861A (fr) 1928-05-10
GB274872A (en) 1928-06-21
BE343779A (enrdf_load_stackoverflow)

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