US1519477A - Signaling system - Google Patents

Signaling system Download PDF

Info

Publication number
US1519477A
US1519477A US501974A US50197421A US1519477A US 1519477 A US1519477 A US 1519477A US 501974 A US501974 A US 501974A US 50197421 A US50197421 A US 50197421A US 1519477 A US1519477 A US 1519477A
Authority
US
United States
Prior art keywords
current
source
station
calling
signaling
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
US501974A
Other languages
English (en)
Inventor
William C Beach
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.)
AT&T Corp
Original Assignee
Western Electric Co Inc
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 Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US501974A priority Critical patent/US1519477A/en
Priority to GB25042/22A priority patent/GB186333A/en
Priority to FR556237D priority patent/FR556237A/fr
Application granted granted Critical
Publication of US1519477A publication Critical patent/US1519477A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone

Definitions

  • This invention relates to signaling systems and more particularly to methods and means for transmitting an audible signal to a calling subscribers station to indicate that the called subscribers station is being signaled.
  • the audible ringing signal is obtained from the regular ringing current source which is generally of a frequency of approximately 16 cycles per second.
  • the signaling tone is due to the higher harmonic components of audible frequency+-generally the so 'calle'd slot ripples of the ringing machine.
  • These harmonic COHIP'ODHtS be ing superimposed upon the 16 cycle current, are accordingly subject to modulation twice each cycle or 32 times per second. This results in a characteristic tone wh'iclrha's come to be well known and which differs from that obtained when the tone is supplied without interruption from a separate source.
  • Serial No, 4599,- 101, of- Fhilip Husta filed September 7, 1921, a circuit arrangement employing a separate source of current for the signaling tone, is disclosed, which is free from the disadvantages outlined above.
  • Figs. 2, 3 and 4 of the drawing show, respectively, the wave forms of the output of the ringing generator, of the signaling current transmitted to the calling subscriber in one or the above mentioned systems, and of the signaling current transmitted to the calling subscriber in the embodiment of the invention shown in Fig. 1.
  • a calling and :1 called subscribers station are shown at A and B, respectively. These may be connected by any well known form of link circuit, such as L, arranged to apply ringing current from a source 1 through an interrupter 2, and a marginal tripping relay 3 to the called subscribers line.
  • an interrupter 4 is provided which is so connected as to modulate alternating current from the source 1.
  • Current from the source 1 is applied to the primary windings 25 of a transformer 5.
  • Current induced in the second ary windings 0t transformer 5 is filtered through a filtering device composed of coils 2'7 and condensers 28. Filtered current is then applied to the calling line, which simulates the modulation of the audible harmonic components of a 16 cycle ringing currentwave, as explained above.
  • the current produced by the source 1 possesses numerous harmonics which affect the wave for n of such current.
  • the higher audible harmonics superimposed upon the lS-cyclc current are transmitted to the calling subscriber through a repeating coil similar to repeating coil 21.
  • the current wave flowing over the calling line assumes in general the form shown in Fig. 3.
  • there may be many more hai. monies present in this current only a suiticient number have been shown to illustrate the form produced. This current has been found to produce a distinctive and pleasing tone in the calling subscribers receiver.
  • the frequency of the resultant current has been selected to correspond with onc ot the prcdoiuihating higher harmonics and the modulated current produces a tone similar in character to that produced by current of the wave shown in Fig. 3.
  • Ringing current is then supplied to the line of station 13 from source 1 over the following path: source 1 of ringing current, collector ring 19, segment 6 and brush 7 of interrupter 2, winding of trippinlg relay 3, lowermost alternate contact of relay 16, ring contacts of plug 14 and jack 15, through the loop of station B, tip contacts of jack 15 and plug 14: and contact 31 of relay 16 to ground.
  • a cir cuit may be traced extending through the source 1 of alternating current, then in parallel, one path extending through the windings of transformer 5 in parallel, contact of relay 9, interrupter 4c, and the other path extending through condenser 32, and thence through the rheostat 34 to ground.
  • the impedance of the first traced circuit from the source 1 is preferably less than the impe lance through the second traced circuit, so that more current flows through the windings 25 than flows through the condenser 32.
  • the purpose of the rheostat 3a is to reduce as desired the amount of current taken from the source 1 for the ringing tone circuit.
  • the values of the condenser 32 and of the windings of the transformer 5 are so chosen that a resonant circuit is formed. Oscillations set up in the resonant circuit tend to strengthen the modulated current which is produced by the interrupter 4:.
  • Current passing through the primary winding of the transformer 5 induces a current in the secondary windings 26 and the flow of current is then as follows: from ground, through the windings 26 of transformer 5 in parallel, through the filtering device including coils 27 and condensers 2S, and thence in parallel, one path extending through the low impedance path through coil 13 to ground, and
  • the function of the filtering device consisting of coils 27 and condensers 28 is to prevent currents without a desired range from passing through to the repeating coil 21.
  • the impedance of the path for the signaling tone through the resistance 13 is low as compared with the path through the re peating coil 21, and the potential drop across resistance 13 is utilized, as in the aforementioned copending application of Philip Husta, to supply signal tone current to station A.
  • the subscriber at station A will accordingly know that the called station 13 is being signaled and the tone which is heard will, by reason of the periodic modulation by the interrupter 1, be similar to that obtained in existing installations from the audible harmonic components of 16 cycle ringing current.
  • relay 3 When the called station answers, relay 3 energizes in the well known manner thereby removing thev shunt from relay 17, whereupon relay 17 operates to shunt relay 16. Relay 16 in releasing, disconnects the signaling current from the called station and the signaling tone current from the calling station.
  • a calling station a called station, a source of signaling current, an interrupter for periodically supplying current from said source to signal said called station and another interrupter for periodically supplying current from said source to signal said calling station.
  • a calling station a called station, a source of signaling current, a plurality of devices for periodically interrupting the flow of current from said source, and means for supplying current through one of said interrupters to signal said called station and through a plurality of said interrupters to signal said calling station.
  • a calling station a called station, a source of signaling current and a plurality of interrupters, one of said interrupters serving to periodically supply currentfrom said source for signaling one of said stations and cooperating with another of said interrupters to supply current from said source to signal the other of said stations.
  • a calling station a called station, a source of signaling current, an interrupter for supplying current from said source to said called station, another interrupter associated With said source, and means controlled by said first mentioned interrupter to control the application of current from said source through said second mentioned interrupter to said calling station.
  • a calling station a called station, a source of signaling current, means for applying current from said source to said called line, means comprising an interrupter, a resonant circuit and a filtering device for modulating current from said source, and means for applying said modulated current to said calling line.
  • a telephone system comprising a calling line, a called line, a source of current, means for modulating current from said source, and means for applying unmodulated current from said source to one of said lines and said modulated current to the other of said lines.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)
US501974A 1921-09-20 1921-09-20 Signaling system Expired - Lifetime US1519477A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US501974A US1519477A (en) 1921-09-20 1921-09-20 Signaling system
GB25042/22A GB186333A (en) 1921-09-20 1922-09-15 Improvements in telephone systems
FR556237D FR556237A (fr) 1921-09-20 1922-09-18 Perfectionnements dans les systèmes de signalisation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US501974A US1519477A (en) 1921-09-20 1921-09-20 Signaling system

Publications (1)

Publication Number Publication Date
US1519477A true US1519477A (en) 1924-12-16

Family

ID=23995781

Family Applications (1)

Application Number Title Priority Date Filing Date
US501974A Expired - Lifetime US1519477A (en) 1921-09-20 1921-09-20 Signaling system

Country Status (3)

Country Link
US (1) US1519477A (fr)
FR (1) FR556237A (fr)
GB (1) GB186333A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2791972A (en) * 1951-10-15 1957-05-14 Gilbert Co A C Vibrator excited loud speaker for toys

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2791972A (en) * 1951-10-15 1957-05-14 Gilbert Co A C Vibrator excited loud speaker for toys

Also Published As

Publication number Publication date
FR556237A (fr) 1923-07-13
GB186333A (en) 1923-07-26

Similar Documents

Publication Publication Date Title
US1519477A (en) Signaling system
US2264397A (en) Power line carrier frequency telephone system
US2375791A (en) Telephone station circuit
US1532207A (en) Signaling system
US1608520A (en) System
US1512933A (en) Signaling system
US2234213A (en) Tone signal source for telephone signaling systems
US2134690A (en) Electrical communication network
US2134691A (en) Electric communication network
US1654929A (en) Amplifier circuits
US1890561A (en) Telephone circuit
US1329001A (en) Telephone system
US2232398A (en) Telephone substation circuit
US1451886A (en) Signaling apparatus for telephone systems
US1608522A (en) Composite ringer circuits
US1778768A (en) Telephone-ringing system
US1315441A (en) Assicwob- to automatic electbic
US1754239A (en) Telephone signaling system
US976961A (en) Combined telephone and service system.
US1808280A (en) Telephone system
USRE22220E (en) Telephone system
US1688475A (en) Substation telephone circuits
US1636330A (en) Substation telephone circuit
US818897A (en) Telephone system.
US1716447A (en) Signaling and transmission circuits