DE759296C - Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections - Google Patents

Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections

Info

Publication number
DE759296C
DE759296C DET54509D DET0054509D DE759296C DE 759296 C DE759296 C DE 759296C DE T54509 D DET54509 D DE T54509D DE T0054509 D DET0054509 D DE T0054509D DE 759296 C DE759296 C DE 759296C
Authority
DE
Germany
Prior art keywords
listening
switching
circuit arrangement
existing telephone
testing devices
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
Application number
DET54509D
Other languages
German (de)
Inventor
Willy Seidel
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.)
Telephon Apparat Fabrik E Zwietusch and Co
Original Assignee
Telephon Apparat Fabrik E Zwietusch and Co
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
Application filed by Telephon Apparat Fabrik E Zwietusch and Co filed Critical Telephon Apparat Fabrik E Zwietusch and Co
Priority to DET54509D priority Critical patent/DE759296C/en
Application granted granted Critical
Publication of DE759296C publication Critical patent/DE759296C/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/738—Interface circuits for coupling substations to external telephone lines
    • H04M1/74—Interface circuits for coupling substations to external telephone lines with means for reducing interference; with means for reducing effects due to line faults

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Function (AREA)

Description

Durch die Erfindung sollen die beim Anschalten, von Mithör- und Prüfeinrichtungen auf bestehende Fernsprechverbindungen auftretenden Knackgeräusche verhindert werden.The invention is intended to be used when switching on, listening in and testing devices cracking noises occurring on existing telephone connections can be prevented.

Es ist bekannt, zur Knackgeräuschverminderung Schaltmitel vorzusehen, welche die in den anzuschaltenden Sprechkreis liegenden ungeladenen Kondensatoren vor ihrer Anschaltung an den stromführenden Verbindungsweg auf ein Potential aufladen, welches etwa den zu erwartenden Potential auf den Adern des Verbindungsweges entspricht. Da das zu erwartende Potential an dem Anschaltepunkt der Mithöreinrichtung an die verschiedenen Verbindungswege unterschiedlich ist, muß bei der bekannten Anordnung ein Spannungsteiler verwendet werden, an dem die entsprechende Spannung für die Vorladung des Kondensators abgegriffen werden kann. Da der Spannungszustand der Sprechleitungen Schwankunggen unterworfen ist, ist ein sicherer Abgleich durch die vorherige Aufladung der Mithörkondensatoren nicht immer gewährleistet, so, daß nicht in allen Fällen. Knackgeräusche vermeidbar sind'.It is known to provide switching means to reduce clicking noise, which are the uncharged capacitors in the speech circuit to be connected charge them to a potential before connecting them to the live connection path, which roughly corresponds to the potential to be expected on the cores of the connection path. Since the potential to be expected at the connection point of the listening device to the different connection paths is different, must in the known arrangement a voltage divider can be used, at which the corresponding voltage for the Pre-charge of the capacitor can be tapped. Since the state of tension of the Speech lines are subject to fluctuations, a safe adjustment is made by the prior charging of the monitoring capacitors is not always guaranteed, so that is not the case in all cases. Cracking noises are avoidable '.

Durch die Erfindung wird eine besonderer Spannungsteller erspart, und es werden mit einem geringen Aufwand an Schaltmitteln mit Sicherheit Knackgeräusche vermieden. Erreicht werden diese Vorteile dadurch, daß in den Anschaltestramkreis in Reihe mit dem Mithörkondensator ein durch eine Taste überbrückbarer Hochohmwiderstand geschaltet ist, der nach der beim Anschalten der Mithör-oder Prüfeinrichtung erfolgenden allmählichen Aufladung des Kondensators durch die Taste kurzgeschlossen wird.The invention saves a special tension plate, and with a small amount of switching means, cracking noises will certainly be heard avoided. These advantages are achieved in that in the connection circuit in series with the monitoring capacitor, a high-ohm resistor that can be bridged by a button is switched, which occurs after the switching on of the listening or testing device gradual charging of the capacitor is short-circuited by the button.

In der Zeichnung ist ein Ausführungsbeispiel der Erfindung dargestellt. Mit VL ist die Leitung bezeichnet, an die über den Mithörschlüssel M1, M2 diie aus einem Fernhörer F bestehende Mithöreinrichtung angeschaltet werden kann. Der in Reihe mit, dem Fernhörer F liegernde Kondensator K wird bein Anschalten, über den Schlüssel, dessen Kontaktfedeirn mit, M1 und M2 untersehieden sind, über den, Hochohmwiderstand Wi allnählich auf das an dem Anschaltepunkt der Verbindungsleitung VL Herrschende Potential geladen. Durch die allmähliche Aufladung des Kondensators wird ein Auftreten von Knackgeräuschen verhindert. Nach der Aufladung des Kondensators, K wird durch die Taste T der Widerstand Wi kurzgeschlossen, damit durch den Widerstand Wi der Abhörstrom nicht geschwächt wird.An exemplary embodiment of the invention is shown in the drawing. VL denotes the line to which you can use the eavesdropping key M1, M2 a remote receiver F existing listening device can be switched on. The in Series with, the remote receiver F lying capacitor K is when switched on, across the Key, the contact springs of which are different with, M1 and M2, via the high-ohm resistor In all cases, what is ruling at the connection point of the connecting line VL Charged potential. Due to the gradual charging of the capacitor, there will be an occurrence prevented by clicking noises. After charging the capacitor, K will be through the button T of the resistor Wi short-circuited, thus through the resistor Wi the Monitoring current is not weakened.

Claims (1)

PATENTANSPRUCH: Schaltungsanordnung zur Verhinderung von Knackgeräuschen beim Anschalten vorn Mithör- oder Prüfeinrichtungen auf bestehende Fernsprechverbindungen unter Verwendung umschaltbarer Widerstände, dadurch gekennzeichnet, daß in den Anschaltestromkreis in Reihe mit dem Mithörkondensator (K) ein durch eine Taste (T) überbrückbarer Hachohmviderstand (11i) geschaltet ist, welcher nach der beim Anschalten der Mithör- oder Prüfeinrichtung erfolgenden allmählichen Aufla:dun:g dies Kondensators durch die Taste (T) kurzgeschlossen wird. ZurAbgrenzung des Erfindungsgegenstands vom Stand der Technik sind im Erteilungsverfahren folgende Druckschriften in Betracht gezogen worden: Deutsche Patentschriften. :\ r. ddS 67.1, 528 o2o, 695 ooo.PATENT CLAIM: Circuit arrangement for preventing crackling noises when switching on the front listening or testing devices on existing telephone connections using switchable resistors, characterized in that a high-resistance resistor (11i) which can be bridged by a key (T) is connected to the connection circuit in series with the listening capacitor (K) is which after the gradual charging of this capacitor when switching on the monitoring or testing device is short-circuited by pressing the (T) key. In order to delimit the subject matter of the invention from the state of the art, the following publications were considered in the grant procedure: German patents. : \ r. ddS 67.1, 528 o2o, 69 5 ooo.
DET54509D 1940-11-10 1940-11-10 Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections Expired DE759296C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DET54509D DE759296C (en) 1940-11-10 1940-11-10 Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DET54509D DE759296C (en) 1940-11-10 1940-11-10 Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections

Publications (1)

Publication Number Publication Date
DE759296C true DE759296C (en) 1953-07-13

Family

ID=7564394

Family Applications (1)

Application Number Title Priority Date Filing Date
DET54509D Expired DE759296C (en) 1940-11-10 1940-11-10 Circuit arrangement to prevent clicking noises when switching on listening or testing devices on existing telephone connections

Country Status (1)

Country Link
DE (1) DE759296C (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE448674C (en) * 1924-11-14 1927-08-25 Aeg Switching device for amplifier
DE528020C (en) * 1928-10-03 1931-06-24 Patra Patent Treuhand Electric light tubes
DE695000C (en) * 1937-11-25 1940-08-14 Siemens & Halske Akt Ges Circuit arrangement for telephone systems to prevent cracking noises when connecting speech sets to existing telephone connections via capacitors

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE448674C (en) * 1924-11-14 1927-08-25 Aeg Switching device for amplifier
DE528020C (en) * 1928-10-03 1931-06-24 Patra Patent Treuhand Electric light tubes
DE695000C (en) * 1937-11-25 1940-08-14 Siemens & Halske Akt Ges Circuit arrangement for telephone systems to prevent cracking noises when connecting speech sets to existing telephone connections via capacitors

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