US1689598A - Telephone substation circuits - Google Patents

Telephone substation circuits Download PDF

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Publication number
US1689598A
US1689598A US64293A US6429325A US1689598A US 1689598 A US1689598 A US 1689598A US 64293 A US64293 A US 64293A US 6429325 A US6429325 A US 6429325A US 1689598 A US1689598 A US 1689598A
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United States
Prior art keywords
circuit
winding
transmitter
substation
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
US64293A
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English (en)
Inventor
Harold C Pye
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.)
Automatic Electric Inc
Original Assignee
Automatic Electric 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
Priority to NL21064D priority Critical patent/NL21064C/xx
Priority to BE336202D priority patent/BE336202A/xx
Application filed by Automatic Electric Inc filed Critical Automatic Electric Inc
Priority to US64293A priority patent/US1689598A/en
Priority to GB17435/26A priority patent/GB260214A/en
Priority to DEA49041D priority patent/DE583007C/de
Application granted granted Critical
Publication of US1689598A publication Critical patent/US1689598A/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
    • H04M1/738—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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/58—Anti-side-tone circuits

Definitions

  • This invention relates in general to telephone substation circuits, but more especially to substation circuits for automatic telephone systems; and the principal object of the invention is to provide a new and improved common battery anti side tone circuit for an automatic telephone.
  • a further object of this invention is to provide an anti side tone substation circuit equipped with a calling device to permit its use in an automatic telephone system.
  • a further object of this invention is to provide a new and improved telephone substation circuit in which are combined the advantages of the well known booster type circuit and the common battery anti side tone circuit.
  • a further object of this invention is to provide an anti side tone booster telephone circuit in which the amount of equipment required is reduced to a minimum without impairing the efficiency of the substation either during the sending or reception of telephone signals.
  • a still further object of the invention is to provide a substation circuit of the class described adaptable for use in a cradle type telephone and using a three conductor cord to connect the monophone to the desk stand.
  • a still further object of the invention is to provide a substation circuit of the class described adaptable to employ either a permanent magnet receiver or a direct current receiver.
  • a further object is to provide an automatic substation circuit in which the transmitter is shunted by a high resistance path through which direct current wili flow to maintain theestablished connection if the transmitter opens its circuit.
  • FIG. 1 shows the invention adapted to use a direct current receiver in an automatic anti side tone telephone substation, this form of substation requiring a four conductor cord comprising conductors (J extending between the bell box and telephone.
  • Figure 4 shows a. modification of the circuit of Figure 1, the modification permitting the reduction of the number of cord conductors from four to three.
  • Fig. 7 I show a substation circuit built in accordance with the objects of this invention and employing a permanent manget receiver instead of the direct current receiver as employed in the other figures.
  • Figures 2 and 3 are respectively the talking circuit and dialling circuit of the substation shown in Fig. 1, while Figs.
  • the substation comprises the usual ringer 1O bridged across the line conductors 1 and 2 in series with the condenser 9; and that the circuit through the calling device impulse spring 3 the hook switch springs 5, the transmitter 7, induction coil winding 13, and the direct current receiver 8, is normally held open by the hook switch springs 5 and 6.
  • the secondary winding 14 of the induction coil is inductively coupled to the primary 3 and placed in multiple with the transmitter T in series with the condenser 9 as is the usual practice in booster telephone circuits in addition to this standard substation equipmcnt, I have provided a third winding in the induction coil, that winding 12, being a relatively large number of turns of fine wire forming a relatively high resistance winding which together with the additional condenser 11 forms a balancing circuit, that circuit being commonly referred to as the artificial line.
  • the manipulation of the calling device operates the shunt springs 4 to short circuit the transmitter and receiver in accordance with the well established practice, the impulse springs 3, operating to open the circuit through the substation connecting the conductors 1 and 2 to operate the automatic switching equipment at the exchangc to set up the call in the well known manner.
  • the windings 12 and 13 of the induction coil are short circuited, and that the winding 14 in parallel with the ringer 10, is bridged across the impulse spring 3 in series with the condenser 9, forming the equivalent oi the iln ulsing circuit shown in the application of Martin, Serial No. 452,467 and filed March 15, 1921.
  • Fig. 2 shows the talking circuit of the substation simplified as much as possible to enable a clear understanding of the operation
  • the condition to be met in a per fect anti side tone substation circuit are a balance for receiving and a balance for transmitting.
  • the substation circuits must be balanced so that no current flows through the receiver, and during receiving when the line is the source of the E. M. F., the substation circuit must be balanced so that no current flows through the artificial line circuit.
  • the balancing circuit would have to be different for each line on which the substation was used, and would be different for each frequency of current sent through the substation.
  • the well designed commercial anti side tone telephone circuit approximates these conditions as nearly as possible, reducing the current flow through the receiver during transmission to such a point as to leave only an unobjectionable receiver response, that response being too weak to be noted.
  • receiving a small current flow through the artificial line its amount being so small asnot to materially decrease the elficiency of the substation.
  • the direct current from the battery feed at the central office passes over the line conductor 1 through the transmitter 7, through the winding 13 of the induction coil, through the direct current receiver 8, through the line conductor 2 and thence back to the central office.
  • the condensers 9 and 11 prevent the flow of any direct current through the windings 14 and 12 of the induction coil, respectively.
  • the action of the voice on the transmitter 7 causes it to vary this direct current changing it into an undulating current, which upon flowing through the winding of 13 of the induction coil, induces in the windings 13 and 14 an alternating current of proportional strength.
  • an E. M. F. will be present across the line conductors 1 and 2, this E. M. F. being alternating and pro ortional to the strength of the signal that is eing received.
  • the current flowing in over the conductor 2 tends to divide into two paths, the one through the artificial line circuit comprising condenser 11 and the winding 12 of the induction coil, and the other path including the receiver 8, the windings 13 and 14 of the induction coil, the condenser 9 and the line conductor 1 and thence back into the external line circuits.
  • the current flowing through the windings 13 and 14 of the induction coil induces in the Winding 12 an electro-motive force in such a direction as to oppose the flow of current through the artificial line.
  • the transmitter 7 being in parallel with the condenser 9 and the winding 14 of the induction coil afio-rds a parallel path for some of the alternating current during receiving.
  • this arrangement is identical to that of the side tone booster circuit, and while it introduces a certain loss, it is unavoidable and not particularly serious.
  • the substation shown in Fig. 4 is a modification of that just explained, the modifications being such as to permit the use of a three conductor cord instead of a four conductor cord.
  • This modification is particularly adaptable when the circuit is used in a cradle type telephone, the three conductor cord comprising conductors C being used between the hand telephone and the desk stand. Because of the similarity of the circuit shown in Fig. 4 and that shown in Fig. 1, the corresponding parts are the same reference numerals in the two figures.
  • This auxiliary path having utility in that it holds the substation circuits closed to direct current even though the transmitter momentarily opens.
  • the resistance of ringer 10 is sufficiently low to hold the battery feed relays at the exchange in an energized position.
  • the undulations in this direct current set up in the winding 13 by the variations caused by the transmitter 7, induce an alternating current in the windings l3 and 14, which flows over two circuits, the one over line conductor 1 through the external circuit to line conductor 2 to the receiver 8, condenser 11, coils 14 and 13, and the other to the winding 12 of the induction coil, the condenser 9, to the line circuit 2 thence over the external line circuit 1, to the windings 13 and 14 and condenser 11.
  • the two ends of the receiver 8 will be at the same potential and no current will flow through it.
  • the alternating E. M. F. impressed on the line conductors 1 and 2 tends to drive the current over two parallel paths, the one to the artificial line comprising conductors 9 and 12, induction coil winding 12, thence through condenser 11, windings 14 and 13 to the line conductor 1, and the ,second path through the receiver 8, thence through the condenser 11 and the windings 14 and 13 to the conductor 1, and the second path through the receiver 8, thence through the condenser 11 and the windings 14 and 13 to the conductor 1.
  • the voltage induced in the winding 12 by the current flowing through the windings 14 and 13 opposes the flow of current through the artificial line included in 9 and 12.
  • the ringer which is bridged directly across the windings 12, condenser 11 and windings 14 and 13 does not materially efl'ect the action of the circuit, except to "guard against the possibility of premature release of the established connection in case the transmitter opens its circuit.
  • the substation circuit that I have shown in Figs. 1 and 4 employ a receiver of the direct current type.
  • Direct current receivers while quite satisfactory in operation of relatively short lines, are not as sensitive as the permanent magnet type receiver, and it is therefore desirable that an anti side tone circuit employsa permanent magnet receiver, particularly if that telephone is to be used on a relatively lon line.
  • the transmitter B current was sent directly to the receiver, serving to polarize it.
  • Permanent magnet receivers are not adapted to handle sufiicient direct current, and the circuit must be changed so that the transmitter feed does not come through the receiver circuit.
  • Anti side tone substation circuits employing a permanent magnet receiver have in the past brought transmitter current through the artificial line, the resistance of which is sufliciently high to seriously impair the eificienc of the transmitter.
  • special low current transmitter must be used in order that the substation will operate satisfactorily.
  • the direct current flowing over this circuit is varied by the transmitter causing an undulating current to flow through the winding 43 of the induction coil, which induces an alternating current in the windings 43 and 42, that alternating current flowing over the circuit including conductor 32, windings 43 and 42, to the condenser 39 to the conductor 31 and thence over the external circuit, joining the undulating transmitter current to reenforce it in the manner of the well known booster circuit.
  • the transmitter as a source of E. M. F., current flows out to the junction point between the windings 42 and 43 of the induction coil and thence divide, part goin through the winding 43 and part through t e winding 42.
  • shunt spring 34 short circuits the winding 44 of the induction coil and the transmitter so that the substation circuit provides an invariable path from conductor 31 to conductor 32 throughthe impulse spring 33 and the winding 43 of the induction coil.
  • the windings 43 and 42 of the induction coil are connected in multiple with the ringer 40, that multiple combination being connected across the impulse springs 33 in series with the condenser 39, an arrangement identical to that of the above mentioned Ma'rtin patent.
  • a group of equipment comprising a ringer, a condenser and an induction coil
  • a second group comprising a transmitter and a receiver
  • circuit means for connecting said elements to form a common battery booster anti side tone circuit said means including a cord ofonly three conductors connected between said equipment groups.
  • a group of equipment comprising a ringer, a calling device, a condenser, and an induction coil
  • a second group of equipment comprisiug a transmitter and a receiver, a three conductor cord connecting said groups together, a line circuit, impulse springs in said calling device arranged to alternately open and close said line circuit, spark quenching means for said impulse springs comprising said ringer and a condenser bridged across said line circuit, a low inductance shunt for said ringer comprising windings of said induction coil, and means comprising a third winding of said induction coil for reducing the inductance of said shunt path to reduce the condenser current through said ringer thereby preventing its tapping during impulsing.
  • a calling device comprising impulse springs and shunt springs, a transmitter, a receiver, a ringer and a condenser, an induction coil, a line circuit across which are bridged said condenser and ringer, a second bridge across said line circuit including said impulse springs, transmitter and one winding of said induction coil, a second winding of said induction coil connected from the junction of said transmitter and first winding to the junction of said condenser and ringer, said first and second windings jointly shunting said ringer, a circuit for said receiver including a third winding of said induction coil, circuits controlled by said shunt springs for short circuiting said transmitter and receiver during the transmission of impulses, spark protective means for said impulse springs comprising said condenser, ringer and shunt circuits, and means comprising said short circuited receiver and said third winding for reducing the inductance of said shunt circuit, thereby still further reducing the condenser
  • a transmitter In a telephone substation, a transmitter, an induction coil and a receiver, a line circuit, a calling device comprising impulse springs and shunt springs, a permanently closed bridge across said line circuit comprising a ringer and a condenser, a second, normally open bridge comprising one winding of said induction coil, said transmitter and said impulse springs, a second winding of said induction coil in multiple with said transmitter, a circuit for said receiver including a third windin of said induction coil, means including said shunt spring for short circuitin said transmitter and receiver during t e operation of said callin device, and circuit means for connecting sai elements together in a balanced circuit so that said receiver is unresponsive to current variations produced in said line by said transmitter.
  • a calling device comprising impulse springs and shunt springs, a transmitter, a receiver, a ringer and a condenser, an induction coil, and a hook switch, a line circuit, a normally closed bridge across said line circuit includin said condenser and ringer, a second bridge including normally open contacts of said hook switch, said impulse s rings, transmitter and a winding of said in action coil, a circuit for said receiver including a second winding of said induction coil and a conductor in common with said second bridge, a shunt circuit for said ringer including a third winding of said induction coil, a set of normally open hook switch contacts and said first induction coil winding, and means including said shunt springs for short circuiting said receiver, transmitter and second induction coil winding to prevent sparking at said impulse springs.
  • an e uipment group comprising a calling device aving impulse springs and shunt springs, a rin er and condenser and a three winding in uction coil,
  • connecting means including a three conductor cord between said unitary structure and 5 apparatus group joining said units to form an automatic anti-side tone telephone substation, and circuit means controlled by said shunt springs for bridging said condenser and induction (oil windings around said impulse springs in a circuit excluding said three conductor cord to prevent sparking during the operation of said calling device.
  • a transmitter In an automatic telephone substation, a transmitter, a receiver, a three winding induction coil, a condenser, a ringer. a calling device having impulse springs and shunt springs, a hook switch and a plurality of contacts controlled thereby, a line circuit. a permanently closed bridge across said line circuit comprising said ringer and con- CERTIFICATE OF Patent No. 1,689, 598.
  • denser a second and normally open bridge across said circuit comprising certain of said hook switch contacts, said impulse springs, transmitter and one winding of said induction coil, a local circuit for said receiver including a second Winding of said induction coil and a conductor in common with said second bridge, said third winding being connected from the common point of said ringer and condenser through a contact set of said hook switch to said common conductor to form with said condenser a shunting means for said transmitter and impulse springs, and to form with said first winding, a shunt means for said ringer.
  • connecting means including a three conductor cord between said unitary structure and 5 apparatus group joining said units to form an automatic anti-side tone telephone substation, and circuit means controlled by said shunt springs for bridging said condenser and induction (oil windings around said impulse springs in a circuit excluding said three conductor cord to prevent sparking during the operation of said calling device.
  • a transmitter In an automatic telephone substation, a transmitter, a receiver, a three winding induction coil, a condenser, a ringer. a calling device having impulse springs and shunt springs, a hook switch and a plurality of contacts controlled thereby, a line circuit. a permanently closed bridge across said line circuit comprising said ringer and con- CERTIFICATE OF Patent No. 1,689, 598.
  • denser a second and normally open bridge across said circuit comprising certain of said hook switch contacts, said impulse springs, transmitter and one winding of said induction coil, a local circuit for said receiver including a second Winding of said induction coil and a conductor in common with said second bridge, said third winding being connected from the common point of said ringer and condenser through a contact set of said hook switch to said common conductor to form with said condenser a shunting means for said transmitter and impulse springs, and to form with said first winding, a shunt means for said ringer.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephonic Communication Services (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
US64293A 1925-10-23 1925-10-23 Telephone substation circuits Expired - Lifetime US1689598A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL21064D NL21064C (fr) 1925-10-23
BE336202D BE336202A (fr) 1925-10-23
US64293A US1689598A (en) 1925-10-23 1925-10-23 Telephone substation circuits
GB17435/26A GB260214A (en) 1925-10-23 1926-07-12 Improvements in automatic telephone substation instrument circuits
DEA49041D DE583007C (de) 1925-10-23 1926-10-24 Schaltungsanordnung fuer nebengeraeuschfreie Teilnehmerstationen in Fernsprechanlagen mit Waehlerbetrieb, deren Sprechtransformatoren mehrere Wicklungen besitzen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US64293A US1689598A (en) 1925-10-23 1925-10-23 Telephone substation circuits

Publications (1)

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US1689598A true US1689598A (en) 1928-10-30

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Application Number Title Priority Date Filing Date
US64293A Expired - Lifetime US1689598A (en) 1925-10-23 1925-10-23 Telephone substation circuits

Country Status (5)

Country Link
US (1) US1689598A (fr)
BE (1) BE336202A (fr)
DE (1) DE583007C (fr)
GB (1) GB260214A (fr)
NL (1) NL21064C (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2643300A (en) * 1947-11-04 1953-06-23 Siemens Ag Albis Telephone subscriber set with sidetone reduction for central battery systems

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2643300A (en) * 1947-11-04 1953-06-23 Siemens Ag Albis Telephone subscriber set with sidetone reduction for central battery systems

Also Published As

Publication number Publication date
DE583007C (de) 1933-08-26
BE336202A (fr)
GB260214A (en) 1927-10-12
NL21064C (fr)

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