US2236499A - Telephone system - Google Patents

Description

April l, 1941.

o. CESAREO ETAL 2.236.499

TELEPHONE SYSTEM Filed Nov. l5, 19259 2 Shee's--SheetI 1 o. CESAREO "WENTOR' RoR/PPE@ B www4@ A TTOR/VEV April 1, 1941. o. cEsAREo ErAL 2,236,499

TLPHONE SYSTEM v l Filed Nov. 15, 1959 2 sheets-sheet z ooaoooooo o o IIHIH A 1 rom/5 Patented Apr. 1, 1941 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM poration of New York Application November 15, 1939, Serial No. 304,480

6. Claims. (Cl. 179-16) This invention relates to the transmission of impulses and particularly to impulse repeaters used in telephone systems.

The object of the invention is to obtain a greater degree of reliability in the operation of' impulse repeaters.

For some purposes it is desirable to use an impulse repeater in which each series of impulses is momentarily stored or registered and is then retransmitted. Usually the incoming series of impulses is registered on a stepping switch which advances and marks a terminal corresponding to the number of impulses, and the number of outgoing impulses is counted by a counting switch which steps over its terminals' until it reaches the position marked by the register switch.

According to the present invention the positions to which the registering switch is advanced in response to the successive incoming series of impulses are marked by space-discharge tubes to measure the extent of the corresponding movements of the counting switch in determining the transmission of the outgoing impulse series. One advantage secured by the use of these tubes is that the register switch, having operated the proper tube to mark a position, is free to resume its forward movement at once in response to the next series of impulses. As the counting switch reaches the marked position its movement is arrested by the presence of the operated tube, and the tube is automatically restored toits normal condition. Another advantage in the use of tubes for marking the positions selected by the register switch is that the marking is positive and remains effective until it is encountered subsequently by the counting switch. That the marking, once established, should remain permanently eiiective until detected by the counting switch is important in the operation of repeaters of this kind, since the counting switch in its movement to control the outgoing impulses may lag considerably behind the register switch, which continues to advance in response to the incoming impulse series.

In the drawings accompanying the detailed specication Figs. 1 and 2 illustrate diagrammatically an automatic telephone system and disclose in detail one embodiment of an impulse repeater incorporating the features of this invention.

The repeater is shown at the incoming end of a trunk T interconnecting an originating automatic olce with a terminating automatic loilce. The originating office includes a line-lnder switch F and a selector S by means of which the calling line I is extended over the trunk T to the termi- 'nating office. The outgoing end of the trunk T may also be provided with an impulse repeater or with the usual trunk control circuit 2.

The incoming impulse repeater in the terminating oice is interposed between the incoming conductors of the trunk T and the first selector l switch S-L 'I'he selector switch S-I has access through succeeding selectors, such as selector S-Z, and through connector switch C to called subscribers lines, such as the line 3. The finder switch F, the selectors S,.S-I and S-Z, and the connector switch C may be of any well-known type, such as those generally employed in stepby-step systems. I

The incoming impulse repeater includes an impulse receiving relay 4, which responds to the impulses transmitted from the calling subscribers dial 5. The repeater also includes a register switch S-3 and a counting switch S-4. These switches may be of the well-known step-by-step type in which the brushes have no normal position. Each switch is provided with four brushes and associated arcuate terminal banks and with a stepping magnet. The banks and brushes of each switch are arranged in pairs, the brushes of each ,pair being positioned on the driving shaft degrees apart so that one brush enters its bank of associated terminals as soon as the other brush of the pair leaves the last terminalof its bank. There are two such pairs in each of the switches; brushes 6 and 'I and brushes 8 and 9, respectivelyLbeing paired in the switch S--3, and

' brushes I0 and II and brushes I2 and I3, respectively, being paired in the switch S-4. The stepping magnets I4 and I5 serve respectively to step the brushes of the switches S-3 and S-4, these magnets being arranged to advance the brushes upon deenergization of their coils.

The positions assumed by the brushes 6 and l of the register switch S-3 are marked by spacedischarge tubes. An individual tube is provided for each terminal position of the brushes 6 and l. These tubes, which may be of any suitable construction, such as the well-known three-element gas-lled type, have their control electrodes connected to the respective terminals in the -switch banks. The anodes of the tubes are connected tothe corresponding positional terminals in the banks associated with brushes I0 and II of the counting switch S--4. Also the anodes areconnected to the sustaining battery through suitable resistance elements. The cathode elements of ving impulses.

register switch S-3 until it reaches'the position marked by the discharged tube. Thereupon the counting switch comes to rest'and ,terminates the transmission of the outgoing impulse series. Depending upon the speed with which the calling party manipulates his dial for each succeeding digit, the counting switch S-4 may orl may not reach the marked position before the register switch S-3 moves away from that position in response to the next succeeding series of incom- Each tube that is fired to mark a terminal position is automatically quenched as soon as the marked position has been reached by the counting switch.

A detailed description will now be given of the' operation of the system. For this purpose it will be assumed that the subscriber of line I in the originating ofce wishes to converse with the subscriber of line 3 in the terminating oiiice. It will also be assumed that the directory number of the called line 3 is 9913 and that the register and counting switches S-3 and S--4 of the repeater are standing in position 3 as indicated by their brushes.

The calling subscriber initiates the call in the usual manner and operates the selector switch S by means of his dial to seize an idle outgoing trunk T extending to the desired called oilice. The trunk control circuit 2 applies the usual guarding potential to the test terminal in the selector S and closes the conductors of trunk T to Voperate the impulse relay 4 of the incoming repeater. The operating circuit of relay 4 may be r traced from battery through the upper winding of the relay, normal contacts of reversing relay I6, lower left winding of repeating coil I1, trunk conductor I8, thence over the loop and returning over trunk conductor I9 through the upper left winding of coil I1 and the normal contacts of relay I6 and the lower winding of relay 4 to ground.

Relay 4 closes an obvious operating circuit for slow-release relay 20. Relay 2D closes a short circuit around the winding of relay 2|. Relay 2| and slow-release relay 22 are normally in an energized condition when the switches S-3 and S-4 are standing in the same position. The energizing circuit for these relays may be traced from battery through the winding of slow-release relay 23, normally closed contacts of 20, conductor 24, brush I2, brush 8, conductor 25 through the windings of relays 22 and 2| to ground. Relay 23, however, is marginal and does not operate in series with the resistance of relay 2|. The operation of relay 20, therefore, as above noted, closes a short circuit around the winding of relay 2|, whereupon relay 2| releases. Relay 20 also opens the circuit above traced for relays 23 and 22.

Relay 2B in operating also closes a circuit from ground over conductor 28 through resistance 29, winding and normal contacts of relay 30 to battery at the left contacts of the pulsing relay 21. Relay 30 operates and locks directly to battery through its lower front contact. Relay 30 atits'f'sl upper contact closes the pulsing loop extending to the succeeding switch S-I. This pulsing circuit may be traced from conductor 3| to the upper right winding of repeating coil I1, winding of polarized supervisory relay 32, lower right winding of coil I1, upper contacts of relay 30 to conductor 33. The closure of this circuit prepares the switch S-I for receiving the next series oi impulses. Relay 30 also closes a circuit from battery through the winding of relay 23, Contact of relay 30, thence over conductor 24, brushes I2 and 8, conductor 25, winding of relay 22 to ground at relay 2U. Relay 23 operates and relay 22 holds in this circuit, relay 2| remaining deenergized. Relay 23 closes an operating circuit of slow-release relay 26 traceable from battery through the winding of the latter relay, front contact of relay 23to ground at the iront contact of relay 20. Relay 26 opens the circuit leading to the windings of the pulse-generating relay 21 to prevent this relay from producing impulses.

When the calling subscriber manipulates his dial to transmit the series of impulses representing the first digit of the called number, namely the digit 9, the impulse relay 4 releases and reoperates in response to each of these impulses. On the iirst release of relay 4 a circuit is closed from ground through the lower armature and back contact of said relay, front contact of relay 20, conductor 34 and thence in parallel through the windings of slow-release relay 35 and magnet I4 to battery. At the end of the rst irnpulse relay 4 reoperates, and magnet I4 deenergizes to step brushes 6, 1, 8 and 9 to the next position. In like manner the switch S--3 advances in response to each succeeding impulse 'of the series and nally comes to rest at the end of nine steps in position I2. In this position brush 6 engages the terminal 36. Relay 35 energizes in the circuit above noted and, being slow to release, maintains its armature operated throughout the impulse series.

As soon as the register switch S--4 takes its first `step in response to the rst impulse, the previously traced circuit for relays 23 and 22 is opened, and these relays release after an interval. Relay 22 closes a circuit from battery through the front contacts of relay, winding of relay 38, contacts of relay 22, closed contacts of relay 39, resistance 4D to ground on conductor 28. Relay 38, however, does not operate at this time since direct battery potential is connected to its winding by way of the closed left contact of the pulsing relay 21, normal contacts of relay 38 and the contacts of relays 39 and 22. When relay 23 releases, as above noted, it opens the operating circuit of relay 26 and this latter relay releases after an interval.

Relays 23 and 36 measure an interval between the commencement of the incoming impulse series and the closure of the operating circuitfor relay 21 to commence the outgoing impulse series. The purpose of this interval is to enable the selector switches to perform their trunk hunting operations between digit series. The operating circuit for relay 21, which is closed as soon as both relays 23 and 26 have released, may be tracedfrom battery through the upper or operating winding of relay 21, normal contacts of relays 26 and 23 to the grounded conductor 28. The operating winding of relay 21 tends to move the armature from its left to its right contact but is delayed in doing so by the biasing winding` of the relay, whiclris energized by charging current flowing to the condenser 4I. As soon, therefore, as the assent@ '38 operates in the circuit above traced. Also, re-

lay 21 in closing its right contact prepares an obvious discharge circuit for condenser 4| through the resistance 42. As the condenser becomes discharged, current increases in the-biasing winding (the interval being measured by the resistance 42) in such a direction that the armature is shifted to its left contact. The engagement of the armature with its left contact results in a circuit from battery through the armature and front contact of relay 38 to the winding of relay 39. This circuit causes the shunting of relay 30, which releases and opens the impulsing circuit extending tothe selector S-I. Relay 38 remains energized in a circuit from battery through the armature and left contact of relay 21, normal contacts of relay 3D, winding of relay 38 through the contacts of relays 22 and 39 and through resistance 49 to the grounded conductor 28. When the impulse relay 21 again attracts its armature to its right contact,

the energizing circuit of relay 3B is opened, and

this relay releases. The next release of relay 21 to its left contact closes the original energizing circuit of relay 39, and the latter relay operates to reclose the impulse circuit. This cycle of operations continues, and measured impulses are transmitted over the conductors 3| and 33 to operate the selector switch S-L For each one of these impulses over the outgoing circuit, relay 38 operates and closes an obvious circuit over conductor 43 to operate the stepping magnet I5 of the counting switch S-4. Switch S-4 takes a step with each impulse transmitted and therefore reaches position I2 upon the transmission of the lastl or ninth impulse for the rst digit of the called subscribers number.

1n the meantime the register switch S-3 has already reached position I2 in response to the incoming series of impulses; and, if the calling party is prompt in transmitting the second digit, the register switch will have advanced out of position I2 before the counting switch reaches this position. Assume this to be the case, namely, that the second series of incoming impulses for the second digit 9 commences before the rst outgoing series has been completed. Following the completion of the first series of incoming impulses, relay 35 released to close the tube ionizing circuit for marking the twelfth position of the register switch S-3. This circuit may be traced from the positive pole of battery 65, resistance 44, closed contacts of relay 22, this relay being deenergized at this time, front contacts of relay, 29, back contacts of relay 35, conductor 45, brush 6, terminal 36 through the ionizing gap of tube 46 to ground. Although this ionizing circuit is closed when relay 35 releases, the tube is not discharged, since a short circuit is closed at the front contacts of impulse relay 4. As soon, however, as the first impulse of the succeeding series is received, relay 4 opens its contact and removes ground potential from the ionizing circuit, whereupon the tube 46 is immediately discharged. Although this discharge circuit extends through the back contact of relay 35, the tube has ample time to ionize its control gap before relay 35 attracts its armature to open the ionizing circuit. The discharge tube 46 is held in an ionized condition over a circuit extending from the positive pole of the anodeA battery 41, resistance 48, through the anode and cathode of the tube 461: ground.

When, therefore, the counting switch S-v-4 reaches position I2 at the end of the first outgoing series of impulses, it finds the position marked by the discharged tube. This marked condition is detected by the operation of relay 49 in a circuit from the positive pole of battery 10 through the Winding of the relay, back contacts of relay 2'6, normal contacts of relay 50, condenser 5|, brush I0, terminal 52 through the discharged tube 46 to ground. Relay 49 'operating in this circuit closes a circuit from battery through its contacts, normal contacts of relay 2'6, winding of relay 39 to ground at the front contacts of relay 20. Relay 39 opens thev circuit of relay 36 to prevent further stepping of the switch S-4. Subsequent operation of relay 30, as above described, operates relay 23, the circuit extending through the contacts of relay 39 to ground at the contacts of relay 39. Relay 23 renders the pulse generating relay 21 ineffective and also reoperates relay 26. Thus theimpulse generating mechanism is disabled at the termination of the outgoing series, relay 21 maintains its armature on its back contact, and relay 30 is operated and locked as above ldescribed to lhold the outgoing loop closed. When relay 49 operates as above noted, it closes an obvious Vcircuit for relay 50, which opens the circuit of relay 49 and places ground potential on conductor 5I. With ground potential on this conductor a shunt circuit is closed through resistance 48 to quench the tube 46. Relay 49 being slow to release releases its armature after an interval and opens the circuits of relays 39 and 59. Relay 39 opens the energizing circuit of relay 23; and, since the original energizing circuit of this relay through the brushes I2 and 8 is still open, the switch S-3 having resumed its operation in response to the second digit, the relay releases after an interval and causes the release of relay 26. The release of these two relays measures the pause between the first and second digits, giving the switch S-I time to perform its trunk-hunting operation. f

With relays 23 and 23 released, the pulsing relay 21 becomes effective, and outgoing impulses are transmitted for the second digit of the called subscribers number. In the meantime, the register switch S-3 advances nine steps in response to thevsecond series of incoming impulses and comes to rest in position 2|, that is, with its brush 6 resting on terminal 69.

The calling subscriber, continuing to dial, next transmits a single impulse representing the third digit of the wanted number, and the register switch takes a single step as explained and comes to rest in its zero position, namely, with brush 1 in engagement with terminal 56. When relay 4 releases in response to this single impulse, the tube ionizing circuit becomes effective, and tube 53 is fired The energized tube locks in its anode circuit, which extends from battery 41 through resistance 54. When, a moment later, the counting switch S--4 reaches the twenty-rst position, relay 49 operates over the circuit previously traced by way of conductor 5|, brush I0, thence over terminal 55 through the discharged tube 53 to ground. Relay 49 causes the cessation of the outgoing impulses for the second digit, and relay 50 operates as explained to quench the tube 53.

Finally the calling party transmits a series of three impulses representing the last digit of the number, and the register switch S-3 advances to its fourth position, namely, with the brush 1 engaging terminal 51. On 'the first impulse 'of the last series relay 4 remove'sgroundfrom 'the tube-firing circuit, and this circuit becomes effective to ionize the tube 58, which is connected to the zero position terminal 56 associated with brush The tube 58 is held energized by means of a circuit from the positive pole of battery 68, resistance 60 through the anode and cathode of tube 58 to ground.

After the inter-digital pause is measured between the second and third digits of the number, the impulse mechanism becomes eiective to transmit a single outgoing impulse to the connector switch C, and the counting switch S-4 takes a single step bringing its brush into engagement with the zero position terminal 59. Relay 49 operates in the circuit above traced over conductor 5| through brush and terminal 59 and thence to ground through the tube 58. Relay 49 terminates the transmission of the third digit and causes the quenching of tube 58.

In the meantime the register switch S-3 advances as above noted in response to the last digit and comes to rest in position 4. Here it remains, since no further impulses are transmitted from the calling line. After the interdigital pause between the third and last digits of the number, the impulse generating mechanism commences the transmission of the last series of impulses to the connector switch C, and the counting switch S--4 steps in synchronism therewith until it reaches position 4. When the counting switch reaches position 4, it does not encounter a red tube, since the impulse relay 4 remains operated following the last digit and maintains the tube-firing circuit ineffective. However, the switches S--3 and S--4 are now standing in the same position at the end of the last digit, and the energizing circuit for relays 23 and 22 is closed when relay 30 operates. This circuit is traceable from battery through the winding of relay 23, front contact of relay 3D, conductor 24, brush I3, terminal 6|, terminal 62, brush 9, conductor 25, Winding of relay 22 to ground at the armature and contact of relay 28. Relay 22 opens the circuit of relay 38 to prevent further stepping of the switch S4, and relay 23 releases relay 26 as above described.

In the foregoing description it was assumed that the calling subscriber commences the dialling for each succeeding digit before the counting switch S-4 reaches the position marked by the register switch 5 3 for the preceding digit. In this case the positions taken by the switch S-3 at the end of each succeeding impulse series are marked by firing the tubes, excepting the last digit, and the counting switch S-4 detects these marked positions by operating the detect ing relay 49 when it reaches them. Relay 49 serves to disable the impulse generating mechanism and to quench the red tubes. In the case of the last digit the tube corresponding to the position reached by the register switch S-3 is not red, since the ionizing circuit is disabled, and the arrival of the counting switch in the final stopping position of switch S-3 is detected by the operation of relay 22, the circuit of which is closed whenever both switches S-3 and S-4 are standing in the same position. Relay 22, in operating, likewise disables the impulse generating mechanism to prevent the transmission of further impulses and to prevent stepping of the counting switch. It is possible, however, that the calling subscriber may delay the transmission of each succeeding digit until the counting switch S-II has reached the stopping position of the Vregisterl switch S'3 for the preceding digit.

If so, the stopping positions of switch S-3 are detected in the manner above described for the last digit of a number.

When the connection is completed through to the called line 3 and the called subscriber answers, current is reversed over the conductors 3| and 33 in the well-known manner, and polarized supervisory relay 32 operates. Relay 32 operates relay I6, which in turn reverses the direction of current flowing over the trunk T to the originating office. This current reversal serves in the well-known manner to operate supervisory apparatus in the calling office.

When the subscribers replace their receivers at the end of conversation, relays 4, 32 and I6 release. Relay 4 also causes the release of relay 2U, which in turn releases relay 23. Relays 22 and 2| now operate in the circuit herein-before traced and remain operated until the repeater is taken for its next use.

Should the repeater be released while the switches S-3 and S--4 are out of synchronism, that is, while these switches are occupying dilerent positions, a circuit is prepared for automatically moving the counting switch S-4 back into synchronism with the switch S-3. This circuit may be traced from battery through the winding and contacts of magnet I5, conductor 63, through the back contacts of relays 2| and 28 to ground. As soon as switch S-4 reaches the position occupied by switch S-S, the previously-traced circuit is closed and relay 2| operates to open th stepping circuit of magnet I5.

While the invention is disclosed in an incoming impulse repeater it is equally applicable to outgoing repeaters. Also, these repeaters may be used in various types of systems and are not limited to the particular system illustrated herein. Furthermore, lit will be apparent that various types of discharge tubes may be used for marking the positions in the register and counting switches. For instance, tubes of the well-known two-element type may be employed if desirable.

What is claimed is:

l. In a telephone system, a repeater comprising a register switch for registering a series of incoming impulses, an impulse transmitter for generating and transmitting a series of outgoing impulses, a counting switch for counting a series of outgoing impulses, means controlled by said impulse transmitter for operating said counting switch, a series of discharge tubes for the successive positions of said switches, each tube having its electrodes connected to the corresponding position terminals of both said switches, means effective following the completion of an impulse series to discharge one of said tubes to mark the position to which said register switch was `set in response thereto, and means controlled through the discharged tube and a terminal of said counting switch to terminate the series of outgoing impulses when said counting switch is advanced to the position corresponding to the position taken by said register switch.

2. In a telephone system, a repeater comprising a register switch, means responsive to a plurali-ty of successive incoming impulse series for advancing said switch progressively over its terminals in a corresponding number of consecutive movements to register said impulse series, a counting switch for counting the successive series of outgoing impulses corresponding to said incoming series, an impulse mechanism for generating and transmitting said outgoing impulses,

a series of discharge tubes for the successive positions of said switches, each tube having its electrodes connected to the corresponding position terminals of both switches, means eiective after each impulse series for discharging a tube to mark the position assumed by said register switch, and meanseiective when the counting switch reaches each marked position for disabling the impulse generating mechanism and for stopping the advance of said conuting switch.

3. In a telephone system, a repeater comprising a register switch, means responsive to a plurality oi' successive incoming impulse series for advancing said switch progressively over its terminals in a corresponding number of consecutive movements to register said impulse series, a counting switch for counting the successive series of outgoing impulses corresponding to said incoming series, an impulse mechanism for generating and transmitting said outgoing impulses, a series of discharge tubes for the successive positions of said switches, each tube having its electrodes connected to the corresponding position terminals of both switches, means effective after each impulse series for discharging a tube to mark the position assumed by said register switch, means effective when the 'counting switch reaches each marked'p-osition for disabling the impulse generating mechanism and for stopping the advance of said counting switch, and timing means for measuring an inter-digital pause between successive movements of said counting switch.

4. In a telephone system, a repeater comprising a register switch for registering a series of incoming impulses, an impulse transmitter for generating and transmitting a series of outgoing impulses, a counting switch for counting a servies of outgoing impulses, means controlled by said impulse transmitter for operating said counting switch, a series of discharge tubes for the successive positions of said switches, each tube having its electrodes connected to the corresponding position terminals of both said switches, means effective following the completion of an impulse series to discharge one of said tubes to mark the position to which said register switch was set in response thereto, means controlled through the discharged tube and a terminal of said counting switch to terminate the series of outgoing impulses when said counting switch is advanced to the position corresponding to the position taken by said register switch, and means controlled by said counting switch for restoring each discharged tube to normal as soon as the counting switch has reached the position marked by such tube.

5. In a telephone system, a repeater comprising a register switch for registering a ser-ies of incoming impulses,4 an impulse transmitter for generating and transmitting a series of outgoing impulses, a counting switch for counting a series of out-going impulses, means controlled by said impulse transmitter for operating said counting switch, a plurality of gas-filled tubes having their control elements connected respectively to terminals of said register switch and having their cathodes connected to a source of potential, means operative after the receipt of said incoming impulse series to apply a potential to the control element of one of said tubes to cause said tube to fire to mark the position to which said register switch was set in response thereto, and means controlled over the conducting path through said fired tube and a bank terminal of said counting switch to terminate the series of outgoing impulses when said counting switch is advanced to a terminal position corresponding to the set position of said register switch.

6. In a telephone system, a repeater comprising a register switch for registering a series of incoming impulses, an impulse transmitter for generating and transmitting a series of outgoing impulses, a counting switch for counting a series of outgoing impulses, means controlled by said impulse transmitter for operating said counting switch, a plurality of gas-iilled tubes having their control electrodes connected respectively to bank terminals of said register switch, having their anodes connected respectively to corresponding bank terminals of said counting switch and having their cathodes connected ,to a source of potential, means operative after the termination of said incoming impulse series to apply ground potential to the control electrode of one of said tubes to cause said tube to fire to mark the position to which said register switch was set in response thereto, and means controlled over the cathode-anode circuit of said fired tube to terminate said series of outgoing impulses when said counting switch is advanced to the terminal thereof to which the anode of the fired tube is connected.

ORFEO CESAREO.

ROBERT O. RIPPERE.

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