US3482051A - Voice-frequency key dialling facility - Google Patents

Voice-frequency key dialling facility Download PDF

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Publication number
US3482051A
US3482051A US512344A US3482051DA US3482051A US 3482051 A US3482051 A US 3482051A US 512344 A US512344 A US 512344A US 3482051D A US3482051D A US 3482051DA US 3482051 A US3482051 A US 3482051A
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United States
Prior art keywords
voice
key
frequency
signal
receiver
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
US512344A
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English (en)
Inventor
Otto Baade
Lorenz Gasser
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International Standard Electric Corp
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International Standard Electric Corp
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Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
    • B21C37/047—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire of fine wires
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/62—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
    • H04B1/64—Volume compression or expansion arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0008—Selecting arrangements using relay selectors in the switching stages
    • H04Q3/0012—Selecting arrangements using relay selectors in the switching stages in which the relays are arranged in a matrix configuration

Definitions

  • the invention relates to voice-frequency key dialling and particularly to the transmission of dial information items from a subscriber station to an exchange.
  • a number of voice-frequency key dialling methods are known which can be divided into two groups.
  • the main problem of all these methods is to provide for so-called speech immunity, i.e. provide measures to assure that no signals are accurately imitated by the voice frequencies.
  • the methods can be subdivided into two groups.
  • the first group of methods provides a signal code at the voice frequencies having characteristics which distinguish it from speech within the voice-frequency band and which can be evaluated via speech immune voice-frequency receivers.
  • a key-signal preferably a D. C. signal, is added to each code signal through which signal standard voice-frequency receivers can be set ready for operation.
  • the methods employing the voice-frequency safe signal code and speech-immunity voice frequency receivers are preferred where a high signalling speed is desired and where lines are inserted into the transmission path, terminating on either end by transformers or capacitors, which cannot transmit D. C. key signals without extra facilities.
  • the disadvantge of these methods is that the receiving devices are more expensive, and in the presence of noise-interference on the line, they can be blocked to signalling.
  • the second group of methods employs standard voice frequency receivers and so-called key signals and do not reach a high signalling speed, because, prior to evaluation of the voice frequency code signal, the key signal must be evaluated and the standard voice frequency receiver connected thereupon.
  • the use of key signals ordinarily requires the addition of means for transmitting DC signals at lines terminating on either end by transformers or capacitors.
  • the big advantage of these methods is, however, that an absolute safety against interfering speech can be obtained and no troubles are to be feared, even if using the methods on lines susceptible to interfering noise.
  • the voice-frequency key dialling method particularly for the transmission of dial information items between subscriber stations and the exchange system is characterized, according to the invention, in that the code signals are formed by a pulsed-DC key-signal (eg, a loop interruption for a short time) and a speech-immunity signal frequency combination (e.g. tones taken two-at-atime). Evaluation of the combined signal may be performed either by speech immunity voice frequency receivers which ignore the key signal, or by standard voice-frequency receivers which are switched ready-foroperation by said key signal. The selection and use of one or the other receiving facility can be made depending upon the conditions expected to prevail. Thus, for any given receiver safe and optimum transmission of information can be assured by use of the appropriate one of the alternative receiver systems.
  • a pulsed-DC key-signal eg, a loop interruption for a short time
  • a speech-immunity signal frequency combination e.g. tones taken two-at-atime
  • a particularly advantageous embodiment of the invention is characterized in this that, on the receiving end, when using standard voice-frequency receivers, the key signal is marked by balancing amplitudes formed by short-time interruptions of the DC signals, e.g. occurring at a line interruption, and that said balancing amplitudes are received by a suitably resigned and inductively connected voice frequency receiver.
  • the key signal can be transmitted via lines, terminating on either end by transformers or capacitors.
  • the short-time loop interruption or loop current reduction is produced, according to the invention, by the switch-over of a contact, particularly a ball-type armature contact with separate breakand make-contact.
  • the speech-immunity signal frequency combinations of the code signals are formed in the two-group code 2 x l-out-of-4 (formed by two tones each taken from a group of four tones), according to a particularly advantageous design.
  • the part of the drawing to the left of the dash-dot line 2 shows the transmitting end, i.e. the subscriber station of a telephone exchange, schematically.
  • the station circuit St is connected, after the handset has been lifted, with the power unit Sp of the exchange via the line L, from which unit the station receives the feeding current.
  • the keys T of the dialling key set are actuated in compliance with the telephone number of the subscriber called.
  • the corresponding voicefrequency code signal is set.
  • a two-group code 2 x 1- out-of-4 a two-frequency generator is provided which furnishes, after actuation of the key, the associated code signal.
  • the switch-over contact u is actuated, too, whereby the station St is switched off and the transmitter TonG switched on. It is thereby assured, that, during the emission of a voice-frequency code signal, speech frequencies produced by the microphone of the station St cannot influence the signalling.
  • the switch-over period of the contact u precedes, as so-called key signal, the voice frequency code signal. This switchover period can be made independent of the duration of pressing the key and independent of the speed with which the keys are actuated.
  • An armature contact may be provided having a separate breakand make-contact and being controlled by a permanent magnet, mounted to a mechanical coupling element. During the switch-over period of contact u the loop current is interrupted or reduced.
  • the right portion of the drawing schematically shows both possibilities; however, it is expected that only one of the illustrated receivers will usually be connected to the line at any given location and any given time, though both might be used, of course, if desired.
  • the top part shows on the receiving end, besides the unit Sp, 2. speech-immune voice frequency receiver TonEl, connected to the line.
  • the type of connection makes no difference for this receiving facility, because the voice-frequency portion of the code signal is immune against speech, and the key signal, accompanying the code signal, can be neglected when evaluating said code signal.
  • the transmission path can be left in an arbitrary manner via lines, terminating on either end by transformers or capacitors, and also via other routes.
  • the lower part shows the second receiving facility. Since only standard voice frequency receivers TonEZ are used the speech immunity must be obtained via the key signal. To this end a receiver SE is provided for the key signal which is switched on only when the standard voice frequency receiver TonEZ responds.
  • the receiver SE can be designed in an arbitrary manner, in order to evaluate the loop interruption or the loop current reduction. Most of the methods known use suitable direct current evaluators which supervise the potentials on the line wires. A particularly advantageous arrangement is obtained, if the balancing amplitudes, occurring at a defined, constant line interruption, and the there-to connected receiving facility are evaluated. Then a correspondingly tuned voice frequency receiver SE is inductively connected with the line, as indicated schematically by the transformer Ue. The capacitor C performs the required disconnection of direct current.
  • a voice-frequency key dialling system for the transmission of dial information between a calling subscriber station and exchange where the exchange includes as components a choice between a speech immune voice-frequency receiver, and a standard voice frequency receiver coupled with a tuned voice frequency receiver, said system comprising:
  • a calling subscriber station including a station circuit and a tone generator
  • the receive end of said line including as components a choice between a speech-immune voice frequency receiver and a standard voice frequency receiver coupled with a tuned voice frequency receiver, where a speech immune voice frequency receiver will respond to said signal frequency combination and a tuned voice frequency receiver will respond to the balancing amplitudes of the pulsed-DC. key signals and switch on said standard voice frequency receiver.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mechanical Engineering (AREA)
  • Signal Processing (AREA)
  • Telephonic Communication Services (AREA)
US512344A 1964-12-15 1965-12-08 Voice-frequency key dialling facility Expired - Lifetime US3482051A (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE1232213 1964-12-15
DEST23083A DE1232214B (de) 1964-12-15 1964-12-15 Tonfrequentes Tastwahlverfahren fuer Fernmelde-, insbesondere Fernsprechanlagen
DEST23082A DE1232213B (de) 1964-12-15 1964-12-15 Tonfrequentes Tastwahlverfahren fuer Fernmelde-, insbesondere Fernsprechanlagen
DEST23097A DE1236026B (de) 1964-12-15 1964-12-17 Wahlaufnahmeeinrichtung fuer Tastwahl-codezeichen, die aus einem Gleichstrom-Vorbereitungszeichen und einer sprachsicheren tonfrequenten Zeichenfrequenzkombination gebildet sind
DEST23111A DE1232215B (de) 1964-12-15 1964-12-19 Tonfrequentes Tastwahlverfahren in Fernmelde-, insbesondere Fernsprechanlagen

Publications (1)

Publication Number Publication Date
US3482051A true US3482051A (en) 1969-12-02

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US512344A Expired - Lifetime US3482051A (en) 1964-12-15 1965-12-08 Voice-frequency key dialling facility

Country Status (8)

Country Link
US (1) US3482051A (de)
AT (1) AT277329B (de)
BE (4) BE673759A (de)
CH (5) CH437439A (de)
DE (4) DE1232214B (de)
FR (1) FR1459635A (de)
NL (4) NL6516306A (de)
SE (1) SE331301B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911223A (en) * 1971-12-02 1975-10-07 Siemens Ag Circuit arrangement for subscriber stations in telecommunications installations, especially telephone installations with auxiliary data traffic

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2332912A (en) * 1942-05-01 1943-10-26 Bell Telephone Labor Inc Telephone system
US3200205A (en) * 1961-06-19 1965-08-10 Int Standard Electric Corp Speech immunity voice frequency signalling system
US3319011A (en) * 1964-05-11 1967-05-09 Bell Telephone Labor Inc Multifrequency signal receiver circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2332912A (en) * 1942-05-01 1943-10-26 Bell Telephone Labor Inc Telephone system
US3200205A (en) * 1961-06-19 1965-08-10 Int Standard Electric Corp Speech immunity voice frequency signalling system
US3319011A (en) * 1964-05-11 1967-05-09 Bell Telephone Labor Inc Multifrequency signal receiver circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911223A (en) * 1971-12-02 1975-10-07 Siemens Ag Circuit arrangement for subscriber stations in telecommunications installations, especially telephone installations with auxiliary data traffic

Also Published As

Publication number Publication date
BE673760A (de) 1966-06-15
DE1236026B (de) 1967-03-09
BE673896A (de) 1966-06-17
BE673897A (de) 1966-06-17
CH437439A (de) 1967-06-15
FR1459635A (fr) 1966-11-18
CH454067A (de) 1968-04-15
CH454967A (de) 1968-04-30
DE1232215B (de) 1967-01-12
NL6516307A (de) 1966-06-20
NL6516301A (de) 1966-06-16
BE673759A (de) 1966-06-15
DE1232213B (de) 1967-01-12
AT277329B (de) 1969-12-29
CH444239A (de) 1967-09-30
SE331301B (de) 1970-12-21
DE1232214B (de) 1967-01-12
NL6516300A (de) 1966-06-16
CH444240A (de) 1967-09-30
NL6516306A (de) 1966-06-20

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