US1809039A - Telephone exchange system - Google Patents

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US1809039A
US1809039A US374357A US37435729A US1809039A US 1809039 A US1809039 A US 1809039A US 374357 A US374357 A US 374357A US 37435729 A US37435729 A US 37435729A US 1809039 A US1809039 A US 1809039A
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relay
line
trunk
station
lead
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US374357A
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Hovland Henry
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AT&T Corp
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Bell Telephone Laboratories Inc
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q3/00Selecting arrangements

Description

June 9, 1931. H. HOVLAND 8 3 TELEPHONE EXCHANGE SYSTEM Filed Jun e 28. 1929 N lNl/ENTDE" w h! HOVLAND ATTORNEY Patented June 9, 1931 UNITED STATES PATENT OFFICE HENRY HOVLAND, OF WILLISTON PARK, NEW YORK, ASSIGNOR T0 BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK TELEPHONE EXCHANGE SYSTEM Application filed. June 28,
This invention relates to telephone exchange systems and more particularly to inrprovements in party line message reglstration.
According to this invention a relay is provided in a two-party subscribers linev circuit for connecting the meter of one of the stations to the tip side of the identification trunk and for connecting the meter of the other station to the ring side of the identification trunk. The winding of this relay is in parallel with the cut-off relay and is operated by booster battery after the called station has answered and the calling station has been identified. This arrangement makes possible a saving of one or more leads between the identification trunk and the line circuit for operating the message registers.
Another feature of this invention resides in so connecting the component parts of the subscribers set as to remove the identifying ground during dialing and thus to make it unnecessary to furnish a pulse repeater in the identification trunk. This arrangement minimizes the amount of equipment in the trunk, obviates the necessity of removing pulse repeating equipment when the connection is extended to an operators position and obviates the difficulty experienced in repeating dial pulses through more than one repeater in multi-ofiice areas.
Referring to the drawings, Fig. 1 represents an automatic telephone system in which this invention is embodied; Fig. 2 shows an alternative arrangement of the equipment at the stations of a two-party line.
In Fig. 1, A and B represent subscribers stations on a party line, one of these being a calling station; D represents a called sub c scribers station; LF represents a line-finder switch which has access to a group of lines including the line to which the stations A and B areconnected; T. represents a trunk whose associated equipment is arranged in accordance with this invention to identify the calling station on a two-party line and to operate the message register which is individual to the calling station; S represents a selector switch which is permanently connected by the trunk T with the line-finder 1929. Serial No. 374,357.
switch LF and which is controlled by the actuation of the calling device at the calling station to select an idle trunk which terminates at a connector switch having access to the line of the called station; C represents a connector switch having access to a group of lines including the line to which the called station D is connected.
The subscribers set at station A is known as the tip subset and is arranged so that the removal of the receiver from the receiver hook connects an identifying ground 46 to the associated line; this subset is equipped with a special dial so as to exclude the receiver from the connection to ground 46. V
The subscribers set at station B is known as the ring subset and is arranged so that no ground is connected to the line by the removal of the receiver from the receiver hook.
The subsets at stations E and F are similar to those at stations A and B except that the dial at station E is of the same type as the dials at stations B and F and the receiver at station E is included in the connection to the identifying ground 47. Each of these identifying ground connections is under the control of the ofi-normal springs of the associated dial, so that the ground is disconnected from the line as soon as the dial is moved oif-normal; this arrangement prevents the identifying ground from interfering with the satisfactory transmission of dial impulses when the various digits of a called subscribers number are dialed. If the identifying ground connection was not opened during dialing, it would be necessary to provide pulse repeating means in the identifying trunk circuit to insure proper operation of the stepby step switches employed in establishing the by the broken lines which connect to the brushes of these switches.
The line-finder LF, which is represented y brushes 8, 9, and 10 and the associated terminals, is similar to that disclosed in United States Patent No. 1,711,682, issued to HoVla-nd May 7, 1929; the brushes 8, 9 and 10 represent one or the two sets of brushes as described in the Patent 1,711,682. The selector switch S which is represented by the brushes 39, 420 and 4:1 and the associated terminals, and the connector switch G, which is represented by the brushes 42, 43 and a l and the associated terminals.- are of the well known Strowger type similar to those described on pages 57 to inclusive of the second edition of Automatic Telephony by Smith and Campbell.
The operation of a system in which the invention is embodied, as represented by the drawings, will now be described in detail. Assume that a call is ori inated by the removal of the receiver from the receiver hook at either of stations A or B.
Line relay 2 operates in an obvious circuit over-the line 1 thereby connecting the winding of the cutoff relay 3 to the sleeve terminal associated withthe line 1 in the bank of line-finder LF; line'relay 2 also connects ground to lead 7 which is effective to cause an idle line-finder to hunt for the terminals of the calling line. During the time that this line-finder, which we will assume to be the line-finder LF, is hunting for the calling line the sleeve lead 14 of the trunk T is connected to ground at the front contact of relay 48 in the line-finder, relay l8 having been operated tostart line finder LF. (For a detailed description of the operation of such a line-finder reference may be had to U. S. Patent 1,711,682.) When ground is thus connected to lead 1 1 a circuit is closed from battery through the winding of the identification test relay 17, through resistance 16, back contact ofrelay 25', lead 15, normally closed contacts of the continuity springsof relay 33, over lead 14 to ground at relay 18 of the line-finder LF. Relay 17 operates in this circuit and closes an obvious circuit for operating relay 18. The circuits for operating relays 17 and 18 are closed-at this time to make certain that these relays are capable of operating when the calling line is tested to identify the callingstation after the connection is released, as hereinafter described. Resistance16 is equal to or greater than the resistance of the longest line to which the line-finder LF has access".
hen the brushes 8, 9 and 10 of the linefinder LF come into contact with the terminals associated with the calling line 1 a circuit is closed from ground relay 48- of the line-finder LF, through sleeve brush l0, and through the front contact of relay 2', to the windings of the cut-off relay 3 and message register control relay l. The cut-off relay 3 operates but relay is marginal and doesnot operate until connected to a higher source of potential, as is hereinafter de scribed. The closing of the circuit through sleeve brush 10 is also effective to stop the hunting action of the line-finder. W'ith the brushes 8 and 9 in contact with the tip and ring terminals of line 1 the line relay (not shown) of the selector S is operated in a circuit which includes leads 11 and 12 of trunk T, the line 1, and the subset at the calling station. (For a detailed explanation of the operation of the selector S reference may be had to pages 61 to 65 ofthe second edition of Automatic Telephony by Smith and Campbell). Ground (not shown) 'is thereupon connected at selector S over the sleeve lead 19 of trunk T, through the lower winding of relay 20, lead 21 n0rmally closed contacts of the continuity springs of relay 25, lead 15, back contact of relay 25, resistance 16, and through the winding of relay 17, to battery. As long as ground at re'l'ay el8 of the line-finder LF is connected to lead 1% of trunk T, as hereinbefore described, relay 20 does not operate for its lower winding is short-circuited by the ground connected to lead 14.-
The operation of the cut-off relay 3 when the line-finder LF finds the calling line, as hereinbefore described, causes the release of the line relay 2. The release of relay 2 disconnects ground from lead 7 whereupon relay l8 releases to disconnect the ground at its front contact from the sleeve brush 10 and from the sleeve lead 145 of trunk T. As a result the lower winding of relay 20 is energized to close its front contacts 22 l and 28 without actuating any of its remaining contacts. The circuit for thus partially operating relay 20 is traced in part from the ground (not shown) at selector S, over lead 19' of the trunk T, through the lower winding of relay 20, lead 21-, and through the normally closed contacts of the continuity springs of relay 25 to lead 15; from lead 15'one branch of the circuit is traced through the back contact of relay 25, resistance 16, and winding of relay 17 to battery; the otherbranch is traced from lead 15, through the normally closed contacts of the continuity springs of relay 38, lead 14:, sleeve brush 10 of line-finder LE, to battery through the windings of cut-oil relay 3 and message register control relay 4 connected in parallel. Relay 17 is held operated in the first mentioned branch of this circuit and cut-off relay 3 is held operated in the other branch. By the aforementioned partial operation of relay 20, a third branch of this circuit is closed from lead 21, through the inner left-hand front contact of relay 18, front contact 22 and: upperwinding of relay 20 to battery; the closing of this branch is eilective to completely operate relay 20; lVith. relay 20 completely operated, ground is disconnected from alarm lead 24 and relay 25 is energized in an obvious circuit.
It is apparent that'the complete operation of relay 20 depends upon the prior operation of relays l7 and 18. If relay 18 has failed to operate the partial operation of relay 2O is effective to operate the alarm circuit 50 by connecting ground. at the front contact of relay 20, through the inner right-hand back contact of relay 25, to lead 24. In this case the closing of the circuit, for operating the calling subscribers message register, is prevented.
)Vit-h relay 25 operated, as hereinbefore described, relays 17 and 18 are released and the alarm lead 24 is transferred to the back contact of relay 20. The release of relay 18 does not cause the release of relay 20 since the winding and front con tact 22 of relay 20 are now connected through the neXt-to-the-outer right-hand front contact of relay 25, to lead 21. In operating, relay 25 also disconnects lead 15 from lead 21 and connects lead 15 to ground through retard coil 26. Thus relay 20 is held operated in the circuit from battery through its upper winding and front contact 22, through the front contact of relay 25, lead 21, lower winding of relay 20 and over lead 19 to ground (not shown) at selector S; the cut-off relay 3 is held operated in the circuit from battery through its winding, brush 10 of line-finder LF, lead 14, normally closed contacts of the continuity springs of relay 33, lead 15, left hand front contact of relay 25, to ground through retard coil 26. This arrangement for holding the cut-off relay 3 operated permits number checking on toll calls. The path for the number checking tone from the sleeve brush 10 of the line-finder is traced through lead 14, normally closed contacts of the continuity springs of relay 33, lead 15, condenser 27, lead 21, lower winding of relay 20, and through the sleeve lead 19 of trunk T to the selector S. No further operation of the trunk equipment occurs until after the connection has been established and the called subscriber has answered, as is hereinafter described.
WVit-h the calling lino extended over the trunk T to the selector S the actuation of the calling device at the calling station is effective to step the brushes of selector S up to the level of a group of trunks which terminate at connector switches having access to a group of'lines including the called line 45. If the call originated at station A, the identifying ground 46 is disconnected from the line, when the calling device is operated, to insure proper operation of the selector S. The selector S then automatically selects an idle trunk in the selected group, thereby extending the connection from the calling line 1 through the brushes 39 and 40 over th selected trunk to the windings of the line relay (not shown) of the associated connector switch C. Ground at connector switch C is then con nected over the sleeve lead of the associated trunk and through the sleeve brush 41 of the selector S to the sleeve lead 19 of trunk T, to hold relay 20 operated; the ground at selector S, hereinbefore described as having been connected to lead 19, is disconnected after trunk T has been extended through the selector brushes to the connector switch. The connector switch now operates in response to the actuation of the calling device at the calling station to extend the connection from selector brushes 39 and 40 through the connector brushes 42 and 43 to line 45 which terminates at the called station D. (For a detailed description of the operation of the Strowger type of selector and connector switches reference may be had to pages 57 to 65 of the second ed1 tion of Automatic Telephony by Smith and Campbell). The called line having been found idle, a source of ringing current having been connected to the called line, and the called subscriber having answered, the source of talking current at the connector C for the calling subscribers line is reversed, with respect to the tip and ring sides of the line, so as to operate the polarized supervisory relay 13 in-the trunk T. The circuit for operating relay 13 be traced from battery, through one side of the line relay (not shown) of the connector C,
th-rough'brush 39 of selector S, upper winding of polarized supervisory relay 13, co11- ductor 11 of trunk T, back contact of relay 28, brush 8 of line-finder LF, over the tip side of the calling line 1, through the subset at the calling station, ring side of line 1, brush 9 of line-finder LF, back contact of relay 28, conductor 12 of trunk T, lower winding of polarized supervisory relay 13, brush 40 of selector S, and through the other winding of the line relay (not shown) of connector C, to ground.
The operation of the polarized supervisory relay 13 closes a circuit from ground through the front contact of relay 13, resistance 29, back contact of relay 31, and through the winding of relay 28 to battery. Relay 28 operates in this circuit thereby disconnecting brushes 8 and 9 from conductors 11 and 12 and connecting both brushes through the back contacts of relay 33, over lead 34 to the winding of identification test relay 17. Relay 28 is slow to operate so that momentary operations of supervisory relay 13 will be ineffective to operate relay 28. Relay 28 also closes an obvious circuit for holding relay 25 operated independent of relay 20 and bridges resistance 30 across the conductors 11 and 12 of trunk T to prevent the release of the line relay (not shown) in con- Cit nector C during the test to identify the calling station. The identification test relay 17, thus connected to the tip and ring sides of the calling line 1, is operated if the call originated at station A since the subset at station A is arranged toconnect the identifying ground 46 to the line when the receiver is removed from the receiver hook. The identification test relay 17 does not operate if the call originated at station B for the subset at this station isdistinguished by the lack of an identifying ground connection.
The operation of relay 28 is also effective to close a circuit from ground through the outer right-hand front contact of relay 25, lead 32, inner lower front contact of relay 28, and through the middle right-hand back contact and the winding of relay 31 to battery. Relay 31 operates in this circuit and looks through its inner right-hand front contact and lead 32 to the same ground, independent of relay 28. If the call originated at station A so that the identification test relay 17 is operated, a circuit is closed by the operation of relay 31 for operating relay 18; this circuit may be traced from battery through the winding of relay 18, front contact of relay 17, lower front contact relay 20, to ground at the inner lefthand front contact of relay 3'1. Relay 18 looks through its right-hand front contact to the same ground independent of relays 17 and 20. Relay 31 is slow to operate so that the momentary operation of relay 17 due to a line charging current will not cause the operation of relay 18. The release of relay 28, which is caused by the operation of relay 31, reconnects brushes 8 and 9 of the line-finder LF to conductors 11 and 12 of trunk T so that conversation may be hadbetween the subscribers at the calling and called stations. No further operation of the equipment associated with the trunk T occurs until the connection is released.
When the connection is released by replacing the receiver on the receiver hook at the calling station, the line relay (not shown) of connector C and supervisory relay 13 of trunk T are released. The selector switch S and the connector switch C are restored to normal in the usual manner. As a result, ground at the connector G is disconnected from the terminal with which the sleeve brush 41 of selector S is in contact thereby releasing relay in the trunk T. The release of relay 20 closes a circuit for reoperating relay 28; this circuit is traced y from battery through the winding of relay 28, outer right-hand front contact of relay 31, outer lower back contact of relay 20, and through the inner left-hand front contact of relay 31, to ground. Relay 20 opens the circuit through the winding of relay 25, but relay is slow to release and the operation nects the winding of test relay 17 through brushes 8 and 9 to the tip and ring sides of the line 1. But if a foreign ground is connected to the calling line, relay 17 is reoperated to prevent the operation of relay 33, as is hereinafter described. By preventing the operation of relay 33, the closing of the circuit for operating the message register is also prevented and ground is connected through the upper back contact of relay 20 and the inner right-hand front contact of relay 25 over lead 24 to operate the alarm circuit 50. v
Assuming that relay 17 does not operate at this time, the operation of relay 28 is effective to close a circuit for operating relay 33; this circuit may be traced from battery through the winding of relay 33, back contact of relay 17, inner lower back contact of relay 20,'middle right-hand front contact of relay 31, inner lower front contact of relay 28, lead 32, to ground at relay 25. Relay 33, in operating, disconnects the ground at retard coil 26 (through the front contact of relay 25 and over lead 15) from lead 14 and connects lead 14 (over lead 38 and through the outer left-hand front contact of relay 31, lamp 37 and resistance 36) to booster battery 35. This results in an increased current through the windings of the cut-off relay 3 and message register control relay 4. The marginal message reglead 14 of line-finder LF when relay 33 operated, the connection to booster battery 35 is effective to prevent the release of the line-finder LF.
With relays 4, 28 and 33 operated the message register which corresponds to the station which originated the call, as identified' by the test relay 17, is operated. If
the call originated at station A, message register 5 is operated in the circuit from battery through its winding, front contact of relay 4, brush 8, front-contact of relay 28, front contact of relay 33, front contact 'ister control relay is thus operated to dis- 1 of relay 18, and over lead 38 to booster battery. It the call originated at station B, message register 6 is operated in the circuit from battery through its winding, front contact of relay 4, brush 9, front contacts of relays 28 and 33, back contact of relay 18, and over lead 38 to booster battery.
The operation of relay 3?), as hereinbefore described, also opened the circuit through the winding of relay 25 and the consequent release of relay 25 opens the circuits through the windings of relays 31 and 33. The release of either of relays 31 or 33 opens the circuits from booster battery 35 but since relay 25 is slow to release this circuit was closed long enough to insure the operation of the calling subscribers register. The opening of the booster battery circuit releases the message register which was operated, releases the message register control relay 1 and the cut-off relay 3 and also causes the release of the line-finder and the return of brushes 8, 9 and 10 to normal. The release of relay 31 releases relay 28 and also releases relay 18, if previously operated. All of the equipment involved in the connection is now normal.
The invention is not limited in its application to a system which employes Strowger type switches and is applicable to all systems which are arranged for party-line message rate subscribers stations.
What is claimed is:
1. In a telephone system, a line having a plurality of subscribers stations, one of which is a calling station, a message register for each of said stations, a selector, means including a trunk for extending said line to said selector, means individual to said trunk for determining which of said stations is the calling station, and means individual to said line for connecting said message registers to said trunk.
2. In a telephone system, a line having a plurality of subscribers stations one of which is a calling station, a message register for each of said stations, a selector, means including a trunk for extending said line to said selector, means associated with said trunk for determining which of said stations is the calling station, a called subscribers line, means including a connector for extending the connection from said selector to said called line, a relay operable by a reversal of current over the talking conductors of said trunk in consequence of the answer of the called subscriber, and means rendered effective by the operation of said relay for operating the register of said calling station over one of the talklng conductors.
3. In a telephone system, a line having a plurality of subscribers stations one of which is a calling station, means said calling station for dialing, an identifying connection at said calling station, and means for opening said identifying connection during the operation of said dialing means and 'for' automatically closing said connection after each opening.
a. In a telephone system, a line having a plurality of subscribers stations one of which is a calling station, means for distinguishing said calling station from the other stations on said line, a dial at said calling station, a selector, means including a trunk for extending. said line to said selector, a pulsing circuit controlled by said dial for selectively operating said selector, and means for disconnecting said distinguishing means when said dial is moved off normal.
5. In a telephone system, a line having a plurality of subscribers stations one of which is a calling station, a dial at said calling station, an identifying connection at said calling station, a message register for each of said stations, a selector switch, means including a trunk for extending said line to said selector switch, meansassociated with said trunk for determining which of said stations is the calling station, acalled subscribers line, means including a connector for extending the connection from said selector switch to said called line, a supervisory relay operable by a reversal of current over the conductors of said trunk in consequence "of the answer of the called subscriber, means rendered effective by the operation of said relay for operating the register of the calling station over one of the talking conductors of said trunk, and means for opening said identifying connection when said dial is moved off normal.
6. In a telephone system, a line having a plurality of subscribers stations one of which is a calling station, a message register individual to each of said stations, a called station, means including a trunk for extending a talking connection from said calling station to said called station, means associated with said trunk for determining which of said stations is the calling station, and a circuit which includes a single talking conductor of said trunk for operating the message register of said calling station.
7. In a telephone system, a line, a plurality of subscribers stations including a calling station permanently connected to said line, a message register "for each of said stations, a called station, means including a trunk for extending a talking connection from said line to said called station, means associated with said trunk for determining which of said stations is the calling station, a circuit including one of the talking conductors of said trunk for operating one of said message registers, and a second circuit including the other talking conductor of said trunk for operating another of said message registers.
l 8. In a telephonesystem, a 1ine,-a-plura1- ity of subscribers stations including a calling station permanently connected to said line, a dial at said calling station an iden- 5 tifying connection at said calling station, a message register for each of said stations, a called station, means including a trunkior extendingv a talking connection fromsaid cal-ling station tosaid called -station,means 16 associated with said trunk for testing said linertodeterminewhich of said'stations is the calling station, a circuitincludin'g a single talking conductor ofsaid trunk for operating that one of said message registers which isindividual to said calling station,
and means for holding said identifying connection openduring the operation of said dial.
9. ,In a telephone system, a line having a 20 plurality of subscribers :stations one of which is a calling station, a receiver and receiver hook at said calling station, an identifying connection at said calling station closed by the removal of said receiver from said receiver hook said receiver being-excluded from said connection,:a dialing .device at said calling station a called station, means including a trunkrfor extending "a connection from said calling station to said called station, means "individual to said trunk for testing said line to determine which of said stations is the calling station, and means for opening said identifying 0011-. nection While saiddiali-ng device is being operated.
' In Witness whereof, I hereunto" subscribe my name this 23d da 0f-'Ma-y,v1929. I
. H NRYH-OVLAND.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426981A (en) * 1942-06-27 1947-09-09 Bell Telephone Labor Inc Automatic toll ticketing alarm system
US2535765A (en) * 1947-07-02 1950-12-26 Automatic Elect Lab Two-party metering and line adapter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426981A (en) * 1942-06-27 1947-09-09 Bell Telephone Labor Inc Automatic toll ticketing alarm system
US2535765A (en) * 1947-07-02 1950-12-26 Automatic Elect Lab Two-party metering and line adapter

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