US2137793A - Telephone system - Google Patents

Description

Nov. 22', 1938- E. N. ANDERSON E'II'AL TELEPHONE SYSTEM Filed Jan. 26, 1938 INVENTORS.

2 Sheets-Sheet 2 E. N. ANDERSON E. L. 6572 By HW ULRICH ATTORNEY.

Patented Nov. 22, 1938 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM New York Application January 26, 1938, Serial No. 186,968

11 Claims.

This invention relates to telephone systems and particularly systems comprising message rate lines.

It is the object of the invention to provide a more efficient, economical, accurate and reliable arrangement for registering calls originated by party-line message rate subscribers.

In telephone systems arranged to provide measured service, it is well known to provide a meter or message register for each individual subscrib ers line and to connect the meter to the sleeve or test conductor of the line equipment in the central office in parallel with the line cut-off relay. When a circuit is closed through the sleeve conductor, upon answer of a call originating over the line, the cut-01f relay operates; but the meter is marginal and does not operate. When the desired connection is completed and the called subscriber answers the call, either manually or automatically operative switching means eiiects the temporary connection of a meter operating battery to the sleeve conductor of the line to cause the operation of the meter without releasing the cut-off relay.

' This invention is a circuit arrangement for determining which. of the subscribers on a twoparty line has originated a call and for operating either one of two meters associated with the line,

the meter for one of the two subscribers being connected to the sleeve conductor of the line in series with a rectifier poled in one direction, the meter of the other of the two subscribers being connected to the sleeve conductor in series with a rectifier poled in the opposite direction, and the line cut-off relay being connected to the sleeve conductor in parallel with both of the meters. A feature of the invention is means effective upon answer of a call originating over a two-party line for connecting the same polarity of operating potential to the sleeve conductor of the line to operate the line cut-off relay as is required to operate the meter of the subscriber who originated the call. A further feature is the momentary connection of a meter operating battery of the re quired polarity to the sleeve conductor of a twoparty line to operate the meter of the calling subscriber without operating the meter of the other subscriber and without releasing the line cut-off relay.

Another feature of the invention is a two-party meter operating circuit arrangement comprising means for, identifying the calling party on a two-party line and for operating one of two metering control relays. dependent upon which of the parties originated the call, the operated control relay being held by the meter operating current to prevent its release while the meter is being operated. A further feature is the provision of a signal for indicating, upon operation of themetering key, failure to identify the calling party or failure to operate the meter in case the metering key was not held operated for a long enough interval or for anyother reason.

These and other features of the invention will be better understood by considering the system shown schematically in the drawings which forms a part of this specification, this system being one arranged in accordance with the invention. It is, of course, understood that the invention is not limited to the particular tele phone system and circuit arrangement shown in the drawing but is generally applicable to measured-service party-line systems.

Referring tothe drawings:

Fig. 1 shows subscribers stations R and T connected to a two-party line LI; and

.Fig. 2 shows an operators cord circuit C and position equipment P, a line L2 and station X.

i The cord circuit C comprises an answering plug 2!, calling plug 3|, a repeating coil RC, supervisory relays 52 and 35 and supervisory lamps 22 and 32. The talking and ringing keys associated with cord circuit C are not shown in the drawing. The sleeve relay 33 completes the connection between repeating coil RC and plug 35 responsive to insertion of plug 3| in the jack of a trunk or line. A 24-volt central oflice battery Bl supplies talking current to calling and called stations, the positive pole being grounded. Battery B2 is a non-grounded battery of 24 volts which is used during test of the calling line to determine which of the two stations is the calling station, the test being made by relay 50 connected in series with a 48-volt battery B5. Batteries B3 and B4 are used to operate the meters of calling stations and have a high enough electromotive force, such, for instance, as 42 to 44 volts, for this purpose. Batteries B3 and B4 are oppositely poled, the positive pole of. battery B3 and the negative pole of battery B4 being grounded. Any battery not otherwise identified in the drawing is the central oifice battery B I. Key 48 and relays 43 and 44 control the connection of meter-operating batteries B3 and B4 to the sleeve conductor 29 01 the cord. Relays 50 to 55, inclusive, and ill to 61, inclusive, are part of the operators position equipment common to a plurality of cords.

The subscribers stations R, T and X are of the usual type employed in common-battery, manually operated telephone systems. Stations R and T differ in that the ringer 5 at station R is normally connected to the ring conductor of line LI and the ringer 9 at station T is normally connected to the tip conductor of the line LI. Stations R and T also differ in that a direct current path is closed from ground through the ringer 9 and contacts of the switchhook II] to the conductors of line LI when the receiver is removed from the receiver hook at station T to originate a call; whereas at station R, condenser 6 is included in the connection between the ringer 5 and both conductors of the line when the receiver is removed from the receiver hook. The line LI is connected in the central oflice to the tip and ring conductors of a jack 20 and through the back contacts of a line cut-off relay I2 to the windings of a line relay II. An answering lamp I3, associated with jack 20, is controlled by relay I I. The line LI is further provided with two meters I5 and I6, both of which are connected to the sleeve conductor I9 in parallel with the cut-off relay. The meter I5 is provided for registering calls originated by station R and is poled by rectifier I 7 to operate when the negativepole of the battery B3 is connected to the sleeve conductor I9; and the meter I6 is provided for registering calls originated by station T and is poled by rectifier I8 to operate when the positive pole of battery B4 is connected to the sleeve conductor I9. Each of meters I5 and I5 are marginal so that the current resulting from connection of battery BI, B3 and B4 to the sleeve conductor I9 is insufficient to cause the operation of either of the meters until the metering key 40is operated.

When one of the subscribers on line LI removes the receiver from the receiver hook, the line loop is closed to energize and operate line relay Relay I I closes a circuit for lighting the answering lamp I3. When the answering plug 2| of cord circuit C is inserted in jack 2|] to answer the call, a circuit is closed from battery-BI through lamp 22, resistor 34, conductor 39, back contacts of relays 43 and 44, conductor 29, sleeve conductors of plug 2| and jack 20, and through sleeve conductor I9 of line LI to the windings of cut-01f relay 2 and meters I5 and I5. Another circuit is closed from battery BI through the left wind- 7 ings of repeating coil RC and the talking conducsupervisory relay 25.

tors of line LI, thereby operating the calling Relay 25 connects resistor 26 in parallel with lamp 22 to prevent the lighting of the lamp as long as the loop over line LI is closed. The electromotive force of battery BI is suificient to cause the operation of the cut-off relay I2; is of a polarity which causes substantially no current through meter I6 and rectifier I8; and although of the required polarity to cause a current through meter I5 and rectifier I1, this current is not strong enough to cause the operation of meter I5. Relay I2 disconnects the windings of line relay I I from the conductors of line LI and relay II releases, extinguishing the answering lamp |3.

After the answering operator is given the number of the station with which the calling subscriber desires connection, a busy test is made in the usual manner. If the called line L2 is idle, the calling plug 3| is inserted in jack 30, thereby closing a circuit from ground in the line circuit through the sleeve conductors of jack 30 and plug 3| winding of relay 33 and through a supervisory lamp 32 to battery. Lamp 32 lights and relay 33 operates. With relay 33 operated, a circuit is closed for operating relay 4 I; this circuit includes the inner upper back contacts of relays 44 and 43,

the lower front contact of relay 33, conductor 39, lower back contacts of relays 43 and 44, sleeve conductors 29 and I9, and the winding of cut-off relay I2. With relay 4| operated, the windings of the repeating coil R0 are disconnected from line LI and the windings of relay 5| are connected in series with non-grounded battery B2 and the line loop. Relay 5| operates and closes a circuit for operating the slow-to-operate relay 52. Relay 52 closes a circuit for holding relay 4| operated; this circuit includes a front contact of relay 4|, the right outer front contact of relay 52, and a back contact of relay 55. Relay 52 also closes a circuit for operating the slow-to-release relay 53 and completes a connection from the negative pole of grounded battery B5 through the winding of test relay 50, left back contact of relay 55, inner right front contact of relay 52, upper front contact of relay 4|, through the tip conductors of plug 2| and jack 20, to the tip conductor of line L|. If the calling station is the station R, there is no ground connection thereat to cause operation of test relay 50; but, if the calling station is the station T, a circuit for operating relay 50 is completed through the middle upper contact of the receiver hook I0 and winding of ringer 9 to ground. A non-grounded battery is used for operating relay 5| so that test relay 50 will not be falsely operated in series with one of the windings of relay 5| in case the call originated at station R. Battery B2 also supplies talking battery to the calling station while the test is being made. The aforementioned operation of relay 53 closes a circuit for operating the slow-to-operate relay 54. Relay 54 locks under the sole control of relay 52 and opens the circuit through the winding of the slow-to-release relay 53. When relay 53 operated and as long as relay 54 is operated, ground is connected through conductor 56 to the armature of test relay 5|] if station R is calling, a circuit is completed through the back contact of relay 50, a front contact of relay 4|, and the middle winding of relay 43; if station T is calling, a circuit is completed through the front contact of relay 50, a front contact of relay 4|, and the middle winding of relay 44. If relay 43 operates, it locks through its inner upper front contact, lower front contact of relay 33, conductor 39, outer lower front contact of relay 43, and through resistor 48 to ground. If relay 44 operates, it locks through its inner upper front contact, inner upper back contact of relay 43, lower front contact of relay 33, conductor 39, lower back contact of relay 43, outer lower front contact of relay 44, and through resistor 48 to ground. The operation of either of relays 43 or 44 opens the operating circuit of relay 4| When the slow-to-release relay 53 closes its back contact, the slow-to-release relay 55 is energized. When relay 55 operates, it disconnects the test relay 5D and opens the holding circuit for relay 4|. Relay 4| releases since its operating circuit was opened by operating either relay 43 or relay 44. The release of relay 4| causes the release of relay 5| and reconnects the conductors of line LI to the repeating coil RC. The release of relay 5| causes the successive release of relays 52, 54 and 55; and relays 50 to 55 are ready for use with another cord. Relays 52 and 54 are slow in operating and relay 53 is slow in releasing to prevent false operation of test relay 50 while the upper contact springs of relay 4| are being actuated, to eliminate the possibility of false operation of relay 50 due to a capacity-discharge from line LI, and to give test relay 5!! sufiicient time to l8. The cut-off relay l2 releases, but is imoperate, if the tip station is calling, before closing the circuit for operating the one or the other of control relays 43 and 44. Relay 55 is slow in operating to allow sufiicient time for the operation of one of relays 43 and 44 before the release of relay 4 I.

If the call originated at station R and relay 43 operates and locks under control of relay 33 as hereinbefore described, relay 43 also closes a locking circuit from the negative pole of meteroperating battery B3, through the lower winding of relay 43 in parallel with resistor 45, inner lower front contact of relay 43, lower back contact of relay 44, conductor 29, and thence to ground through the winding of cut-off relay l2 and through the winding of meter l5 and rectifier l1. Relay I2 is held operated, but due to the resistance of the lower winding of relay 43 and resistor 45, the current through the windings of meter 15 is not strong enough to cause operation of this meter; and due to the polarity of battery B3 there is substantially no current through meter l6 and rectifier l8.

If the call originated at station T and relay 44 operates and locks under control of relay 33 as hereinbefore described, relay 44 closes a locking circuit from the positive pole of meter-operating battery B4, through the lower winding of relay 44 in parallel with resistor 46, inner lower front contact of relay 44, conductor 29, and thence to ground through the winding of cut-off relay [2 and through the winding of meter 15 and rectifier mediately reoperated, when the negative pole of battery BI is disconnected and the positive pole of battery B4 is connected to sleeve conductor l9. Due to the resistance of the lower winding of relay 44 and resistor 46, the current through the windings of meter I6 is not strong enough to cause operation of this meter; and due to the polarity of battery B4 there is substantially no current through meter l5 and rectifier H.

The called station is signalled by operation of a ringing key (not shown) in usual manner and when the subscriber at station X answers the call, the supervisory relay 35 operates. Relay 35 connects resistor 36 in parallel with lamp 32 to extinguish the lamp. The talking circuit includes the windings of repeating coil RC. To charge the calling station for the call, the non-locking metering key 4|] is momentarily operated. If the call originated at station R, the metering circuit is traced from meter operating battery B3, through the lower winding of relay 63 in parallel with the winding of relay 65, lower back contact of relay 6|, upper winding and outer upper front contact of relay 43, outer upper back contact of relay 44, contacts of key 40, conductor 29 and I9, through the winding of cut-off relay l2 and through the winding of meter [5 and rectifier I1. Relay I2 is held operated and meter I5 is operated; rectifier I8,

prevents the operation of meter l6; Meter l5 short-circuits its left winding and rectifier ll and looks through its low-resistance right winding. Although the lower winding of relay 43 is shunted by the windings of relays 63 and 65 while key 40 is operated, the energization of the upper winding of relay 43 insures the continued operation of this relay while key 40 is operated. Relay 63 is operated by the current through its lower winding in series with both windings of meter l5 but relay 65 is marginal and does not operate until meter 15 operates and short-circuits its left winding. Relay 63 closes a locking circuit from battery through lamp III, upper front contact and upper winding of relay 63, through resistor 68 to ground.

Resistor 68 limits the current sufficiently to prevent lighting of lamp 10. At itslower front contact, relay 63 connects interrupter "H to the winding of relay B1 and relay 6'! is thereby alternately operated and released under control of the interrupter. Each operation of relay 31 short-circuits resistor 68, thereby lighting lamp It. If the meter l5 fails to operate lamp I continues to flash under the control of relay 61; but, if meter 15 operates, the short-circuiting of the left winding of meter l causes the operation of relay 65. Relay 65 closes a circuit for operating the position register 63; and register 69 closes a circuit through the middle winding of relay 6|. Relay 6| operates, closes a holding circuit through its lower winding in series with meter l5 and meter operating battery B3, and closes at its outer lower front contact a circuit for lamp l0. Lamp H1 is thereby continuously lighted until key 43 is released. The upper winding of relay 63 is short-circuited when relay 6| operates and the resistance of the lower winding of relay 6| reduces the current through the lower winding of relay 63 and the winding of relay 65 to cause the release of relays 63 and 65 without causing the release of the meter 15. The release of relay 65 causes the release of register 69 and the release of register 39 deenergizes the middle winding of relaytl. When key 40 is released, relay 6! releases but the cutoff relay I2 is held in series with the lower winding of relay 43 and battery B3; and the meter I5 is held operated by its right winding in series with the lower winding of relay 43 and battery B3 to prevent a second operation of meter iii in case the contacts of key 43 are closed a second time. If the call originated at station T and control relay 44 is operated, the operation of metering key 40 closes a circuit from battery B4 through the lower winding of relay 64 in parallel with the winding of relay 66, upper back contact of relay 6i, upper winding and outer upper front contact of relay 44, contacts of key 43, conductors 29 and I9, through the winding of meter i3 and rectifier I8. Relay I2 is held operated and meter [6' is operated; rectifier ll prevents the operation of meter 15. Meter l6 short-circuits its left winding and locks through its lowresistance right winding. Although the lower winding of relay 44 is shunted by the windings of relays 54 and 65 while key 43 is operated, the energization of the upper winding of relay 44 insures the continued operation of this relay while key 40 is operated. Relay 64 is operated by the current through its upper winding in series with both windings of meter it but relay 66 is marginal and does not operate until meter 13 short-circuits its left winding. Relay 64 closes a locking circuit from battery through lamp 13, lower front contact and lower winding of relay 64, through resistor 68 to ground; and connects relay E1 to interrupter II to flash lamp until the meter Hi operates. When relay 33 operates due to the short-circuiting of the left winding of meter it, it closes a circuit for operating register 39 and register 69 causes the operation of relay 6|. With relay 6| operated, lamp Wis lighted continuously and relays E54 and E3 and register 39 release. When the key 40 is released, relay 3| releases and lamp I0 is extinguished. The cut-off relay I2 is held in series with the lower winding of relay 44 and battery B4; and the meter 16 is held operated in series with the lower Winding of relay 44 and battery B4 to pre-' vent a second operation of register 16 in case the contacts of key 40 are closed a second time.

If neither one of control relays 43 and 44 is operated when metering key 40 is operated, a circuit is closed over sleeve conductors l9 and 29, through key 40 and the outer upper back contacts of these relays for operating relay B2 of the position equipment P. Relay 62 closes a circuit through resistor 68, the upper winding of relay 63 and lamp 'lll. Relay 63 operates, thereby connecting relay '61 to interrupter 7|. Relay 63 is locked through its upper Winding independent of relay G2 and the lamp 10 continues to flash until the trouble is cleared and relay 6| is operated.

When the conversation is completed, the placing of the receiver in normal position at the called station X causes the release of relay 35 and the lighting of lamp 32; and the placing of the receiver in normal position at the calling station R or T causes the release of relay 25 and the lighting of lamp 22. When the operator removes plugs 2i and 4| from jacks 20 and 40, the cut-off relay l2 .and the operated one of relays 43 and 44 releases.

What is claimed is:

1. In a communication system, lines including a two-party line, a relay for said line, a call meter for each of the stations of said line, a test conductor for said line, the windings of said relay and meters being connected in multiple to said conductor, a rectifier in series with one of said meters, an oppositely poled rectifier in series with the other of said meters, a link for use in interconnecting calling and called lines, a source of current effective upon interconnec- :tion of the link and said line to operate said relay but having insuffioient electromotive force to cause the operation of either of said meters, other sources of current associated with said link, means for determining on a call originating on said two-party line the station at which the call originated, means effective upon identification of the calling station to connect to said test conductor to operatively energize said relay a source of current of the same polarity as is re- .quired for operating the meter of the calling station, and means comprising a key for operating the meter of the calling station.

2. In a communication system, lines including a two-party line, a relay for said line, a call meter for each of the stations of said line, a test conductor for said line, the windings of said relay and meters being connected in multiple to said conductor, a rectifier in series with one of said meters, an oppositely poled rectifier in series with the other of said meters, a link for use in interconnecting calling and called lines, a source of current effective upon interconnection of the link and said line to operate said relay but having insufficient electromotive force to cause the operation of either of said meters, other sources of current associated with said link, means for determining on a call originating on said two-party line the station at which the call originated, means effective upon identification of the calling station to connect to said test conductor to operatively energize said relay a source of current of the same polarity as is required for operating the meter of the calling station, the last-mentioned connection being ineffective to cause the operation of either of said meters, and means comprising a key for operating the meter of the calling station and for holding said relay operated while the meter is being operated.

3. In a communication system, lines including a two-party line, a relay'for said line, a call meter for each of the stations of said line, a test conductor for said line, the windings of said relay and meters being connected in multiple to said conductor, a rectifier in series with one of said meters, an oppositely poled rectifier in series with the other of said meters, a link for use in interconnecting calling and called lines, a source of current effective upon interconnection of the link and said line to operate said relay but having insuificient electromotive force to cause the operation of either of said meters, other sources of current associated with said link, one of said other sources of current having sufiicient electromotive force and the required polarity for operating one of said meters, another of said other sources having sufiicient electromotive force and the required polarity for operating the other of said meters, means for determining on a call originating on said two-party line the station at which the call originated, means effective upon identification of the calling station to connect to said test conductor to operatively energize said relay a source of current of the same polarity as is required for operating the meter of the calling station, the last-mentioned connection being ineffective to cause the operation of either of said meters, and means comprising a key for operating the meter of the calling station and for holding said relay operated while the meter is being operated.

4. In a communication system, lines including a line having two stations permanently connected thereto, a link for use in interconnecting calling and called lines, a relay connected to the test conductor of said line, a meter for each of said stations, each of said meters being connected to said test conductor in parallel with said relay, a rectifier in series with each of said meters, said rectifiers being oppositely poled, means comprising a current source in said link for operating said relay upon interconnection of said link and said line without operating either of said meters, two oppositely poled sources of current in said link each of high enough electromotive force for use in operating the one or the other of said meters, means associated with said link for determining which of the two stations on said line is the calling station, means including the one or the other of said oppositely poled sources of current for operatively energizing the winding of said relay without causing the operative energization of either of said meters, and means comprising a key for connecting one or the other of said oppositely poled sources of current to the test conductor of said line to operatively energize the winding of said relay and the winding of the one or the other of said meters.

5. In a communication system according to claim 4, circuit means for preventing the connection of the first-mentioned current source to said test conductor while said key is operated.

6. In a communication system, lines including a two-party line, a first relay, a call meter for each of the stations of said line, a test conductor for said line, the windings of said first relay and meters being permanently connected in multiple to said conductor, a rectifier in series with one of said meters, an oppositely poled rectifier in series with the other meter, a link for use in interconnecting calling and called lines, a source of current effective upon interconnection of the link and said line to operate said first relay but having insuflicient electromotive force to cause the til operation of either of said meters, other sources of current associated with said link, two metering control relays, means for determining on a call originating on said party line the station at which the call originated and for thereupon selectively operating the one or the other of said control relays, means comprising holding windings and contacts of said control relays for connecting to said test conductor to operatively energize said first relay a source of current of the same polarity as is required for operating the meter of the calling station, and means comprising a key for operating the meter of the calling station and for holding the operated one of said control relays while said meter is being operated.

7. In a communication system, lines including a two-party line, a first relay, a call meter for each of the stations of said line, a test conductor for said line, the windings of said first relay and meters being permanently connected in multiple to said conductor, a rectifier in series with one of said meters, an oppositely poled rectifier in series with the other meter, a link for use in interconnecting calling and called lines, a source of current efiective upon interconnection of the link and said line to operate said first relay but having insufficient electromotive force to cause the operation of either of said meters, other sources of current associated with said link, two metering control relays, means for determining on a call originating on said party line the station at which the call originated and for thereupon selectively operating the one or the other of said control relays, means comprising holding windings and contacts of said control relays for connecting to said test conductor to operatively energize said first relay a source of current of the same polarity as is required for operating the meter of the calling station, the last-mentioned connection being ineffective to cause the operation of either of said meters, and means comprising a key for operating the meter of the calling station and for holding said first relay and the operated one of said control relays while said meter is being operated.

8. In a communication system according to claim 1, a signal, and means rendered effective upon operation of said key for operating said signal.

9. In a communication system according to claim 3, a signal, and means in the circuit for operating either of the meters for initiating and continuing the operation of said signal until the meter of the calling station is operated.

10. In a communication system according to claim 1, a signal device, means in the circuit for operating either of the meters for initiating the operation of said signal device, and means responsive to the operation of the meter of the calling station for operating said signal device in a different manner.

11. In a communication system according to claim '7, a signal device, means in the circuit for operating either of the meters for initiating the operation of said signal device, and means effective in case neither of said control relays is operated when said key is operated for initiating the operation of said signal device.

EMIL N. ANDERSON. EMIL L. GETZ. HORACE W. ULRICH.

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