US1823665A - Telephone system - Google Patents

Telephone system Download PDF

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Publication number
US1823665A
US1823665A US390155A US39015529A US1823665A US 1823665 A US1823665 A US 1823665A US 390155 A US390155 A US 390155A US 39015529 A US39015529 A US 39015529A US 1823665 A US1823665 A US 1823665A
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relay
armature
circuit
switch
battery
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US390155A
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Paulett William Henry
Gillings Charles
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Associated Telephone and Telegraph Co
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Associated Telephone and Telegraph Co
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements

Definitions

  • the present invention relates to telephone systems and is more particularly concerned with arrangements for holding switches operated in such systems and for providing arrangements for testing whether a line is free or busy.
  • a well-known type of telephone system employs step-by-step switches which are guarded by the application of earth potential to the test contacts, the absence of earth potential from the test contacts being employed to indicate that the switch s in a condition to be taken into use for setting up aconnection.
  • One object of the p esent invention is to mark the idle condition of the switches in a more positive manner without complicating the circuit details or the construction of the switches and this is effected according to one feature of the invention by connecting one 'pole of battery to the associated test contact when a line is free and connecting the other pole of battery to the associated test contact when a line is busy.
  • a holding conductor which is adapted to maintain.
  • a plurality of switches operated extends over the test wipers of the switches, potential different from that used for holding being employed to designate an idle line.
  • Fig. 1. represents an intermediate group selector, that is to say one in which all br1dges across the line are cut out and a straight-through connection obtained when the switch has been completely set.
  • This switch may be taken into use either from a lineswitch or from a selector which may be of simllar type or may be. of the battery feeding type.
  • Fig. 2 indicates a similar switch provided however withtwo sets of wipers and corresponding bank contacts and arranged for simultaneous hunting over both banks so that testing of two lines takes place at the same time.
  • Fig. 3 is a first selector with transmissio bridges for supplying feed current to the calling party and giving operator hold facilities. This switch is accessible from a subscribers lineswitch.
  • Fig. 4 is an incoming selector accessible over a two-conductor trunk line.
  • Fig. 5 is a final selector or connector which connects directly with a wanted partys line and supplies ringing current and subsequently battery feed to the wanted line.
  • Fig. 6 shows a first selector substantially similar to Fig. 3 except that it is arranged for metering at the end of the conversation rather than upon the reply of the called party.
  • Fig. 7 is a first selector similarly arranged for metering at the end of a conversation, but in this case by a booster impulse over the test lead instead of by connection of potential to a separate metering lead.
  • relay A When the next series of impulses is transmitted, relay A will de-energize intermittently and on each deenergization will com- 7 plete a circuit from earth, armature 7 and its back contact, armature 10 and its back contact, winding of relay 0, armature 15 and its front contact, cam springs 21, winding of vertical magnet V to battery.
  • the vertical magnet is accordingly energized intermittently and operates to raise the wipers 2729 a corresponding number of steps.
  • Relay C which is slow to release remains energized throughout the impulse series and at armature 16 opens a point in the rotary magnet circuit.
  • Wipers 2729 are accordingly advanced one step to engage the first set of contacts in the level chosen and the magnet also operates the springs 19 therebcy;Ir completing a circuit for relay G.
  • Relay at armature 18 prepares a testing circuit for relay H and at armature 17 opens the circuit of the rotary magnet so that this magnet de-energizes and opens the circuit of relay G.
  • wiper 27 will encounter battery and a circuit will then be completed to cause the operation of relay H. If the line is in use, however, there will be earth on the associated test contact or in case the test lead should be broken the contact will be dead and in either case it will be impossible for relay H to operate.
  • relay G de-energizes, a circu1t is again completed for the rotary magnet and the same cycle of operations takes place, the wipers being advanced a further step. This continues until a free line is encountered, whereupon relay H energizes over its lower winding and at its lightly-tensioned subsequently.
  • Relay B is sufficiently slow to ensure that earth shall be maintained on the test conductor until it is fed back from the switch just taken into use. It may be pointed out that the provision-of a make spring connected to earth for off-normal spring 24 is only necessary in the case in which the switch is accessible from a rotary lineswitch which is arranged to hunt for absence of earth in the usual manner.
  • the release of the switch is brought about by the removal of earth from the test conductor whereupon relay H is de-energized and at armature 7 completes a circuit for the release magnet Z in series with relay C which accordingly operates though without useful effect at this time. It will be noted that the switch is not rendered available for re-seizure until it has reached its normal position whereupon and the circuit of the release magnet is opened at springs 2'".
  • Fig. 2 the circuits of the switch there shown are similar except that the switch is provided with two sets of wipers arranged for simultaneous hunting. Moreover the guarding circuit is slightly different in that the battery potential indicating the idle condition is applied over a back contact of relay C andaccordingly the switch is not available for use until a short interval after the operation of the release magnet.
  • relay A de-encrgizes intermittently and sends a corresponding number of pulses to the verti*al magnet which operates to raise the wipers 83-88 to the desired level.
  • Relay C is energized in series with the verti .al magnet throughout the train of impulses and at armature 73 maintains the circuit of the rotary magnet open.
  • ⁇ Vhen relay C de-energizes, however, magnet R is energized to rotate the wipers one step into engagement with the first set of bank contacts and at springs 76 to complete a circuit for relay G.
  • This relay at armature 74 opens the circuit of the rotary magnet thus causing it to open contacts 76 and at armature 75 completes the test circuit for relays HA and HB. If test wipers 85 and 88 both fail to encounter battery due to the associated lines being busy or out of order, neither of these relays can operate and on the de-energization of relay G the rotary magnet is again energized to advance the wipers another step. If wiper 88 now encounters battery while wiper 85 encounters earth relay HB will be shortcircuited but a circuit will be completed from battery on wiper 88 over bank contact and armature 61, lower winding of relay HA, front contact and armature 69, front contact and armature 75 to earth.
  • Relay HA upon operating in this circuit, at armatures 54 and 59 switches leads 51 and 52 through to wipers 86 and 87, at armature 55 feeds earth forward to wiper 88 to busy the seized line,at armature 56 disconnects wipers 85, at armature 57 completes a locking circuit for itself over its upper winding and at armature 58 opens a point in the circuits of the release and rotary magnets.
  • wiper 85 had encountered battery while wiper 88 had encountered earth
  • relay HB would have operated and at armature 6065 would have produced similar changes to those produced by relay HA.
  • wipers 85 and 88 both encountered battery both relays HA and HB would have commenced to operate but owing to the fact that relay HE is provided'with a copper slug which makes it slightly slow to energize relay HA energizes first and at armature 56 opens the circuit of relay HB.
  • relay HE is provided'with a copper slug which makes it slightly slow to energize relay HA energizes first and at armature 56 opens the circuit of relay HB.
  • the release of the switch takes place when earth is removed from the test conductor whereupon relay HA or HB as the case may be'will deenergize and complete a circuit extending from earth, back contact and armature 64, armature 58 and its back contact, armature 66 and its back contact, winding of relay C, armature 71 and its back contact, olf-normal springs 81, winding of release magnet Z to battery.
  • Magnet Z and relay C operate in series in this circuit, the former restoring the switch shaft and wipers in the usual manner and the latter at armature 72 applying earth to the test conductor 53 in place of battery so as to prevent seizure of the switch at that time.
  • oft-normal springs 81 will open and relay C will commence to release so that after a short interval battery will be replaced on test conductor 53 and the switch will be available for further seizure.
  • this shows a battery feeding first selector which is assumed to be accessible from a rotary lineswitch of the type which hunts for absence of earth so that it is unnecessary to provide a battery connection to the test conductor to indicate that the switch is in condition to be seized.
  • This switch is also provided with arrangements for metering over a fourth wire when the called party replies.
  • relay A When the switch is taken into use, relay A is energized over leads 101 and 102 and the calling loop and at armature 105 prepares a circuit for repeating impulses to succeeding switches and at armature 106 completes a circuit for relay AB.
  • Relay MD completes a locking circuit for itself at armature 126, at armature 127 opens a point in the metering circuit and at armature 128 closes a point in the operator hold circuit for relay 1. Moreover at this time dial tone from lead 140 is connected up over off-normal springs 132 to conductor 101 to indicate to the callin party that he may now operate his dia switch. a
  • relay A When the first series of impulses is transmitted, relay A de-energizes intermittently, thereupon at armature 106 transmitting a corresponding'number of pulses to the vertical magnet V which accordingly operates to raise the wipers 137139 a corresponding number of steps.
  • Relay 0 which is slow to release is energized in series with the vertical magnet throughout the impulse series and at armature 115 opens a point in the circuit of the rotary magnet, another point being closed at springs 135 as soon as the switch goes offnormal.
  • relay C de-energizes and a circuit is then completed from earth, armature 109 and its front contact, back contact and armature 119, armature 115 and its back contact, off-normal springs 135, armature 125 and its back contact, winding of rotary magnet B to battery.
  • Magnet B accordingly advances the wipers 137-139 into engagement with the first set of bank contacts and at springs 136 completes a circuit for relay G which thereupon at armature 119 opens the circuit of the rotary magnet and at armature 118 completes a testing circuit for the upper winding of relay H to test wiper 139.
  • relay H will be unable to energize and when relay de-energizes due to the release of rotary magnet R, the circuit of this magnet will be again completed and it will operate to ad vance the wipers a further step.
  • battery picked up by wiper 139 will be extended over armature 111 and its front contact, upper winding of relay H, front contact and armature 118 to earth.
  • a loop is now completed across wipers 137 and 138 which extends as follows: wiper 137, armature 120 and its front contact, armature 105 and its front contact, left-hand winding of polarized relay D, winding of relay 1, front contact and armature 125, wiper 138 and this loop serves to prepare the succeeding switch for operation in the usual manner.
  • relay A pulses as before and at armature 105 intermittently opens the loop circuit just traced so as to produce operation.
  • relay D will deenergize and again complete a circuit for the lamp CSH which accordingly serves to indicate when the called party is being held by the calling party.
  • relay A de-energizes and at armature 105 opens the loop extending to the succeeding switches so as to cause their release in the usual manner and at armature 106 opens the circuit of relay AB and completes the circuit of relay C.
  • Relay AB on de-energizing after a short interval opens the circuit of relay B which thereupon at armature 110 connects up armature 113 which is at this time in operated position.
  • Relay B also at armature 112 completes a circuit for release magnet Z, in series with relay C and the magnet operates to release the switch. Earth is maintained on test conductor 103 until restoration is complete and the circuit of magnet Z and relay 0 is accordingly opened at off-normal springs 134.
  • relay I is maintained energized and at armature 116 provides an alternative c1rcuit for relay B so that release cannot take place until battery is removed from the lower speaking lead when the operator takes down the connection.
  • this shows an 1ncoming selector, that is to say, a selector which is adapted to be seized over a two-wire junction so that in this case it is clearly impossible for the switch to feed back battery on the test conductor in order to indicate 1ts idle condition.
  • the arrangement adopted is that in the bank of the switch having access to the outgoing and of the trunk line a permanent battery connection is made to the associated test contact so that if the trunk line is tree this battery connection will be effective. If, however, the line is in use earth will be connected to the test contact in the usual manner, and this will have the eflect of rendering the battery connection ineli'ective.
  • relay A de-energizes intermittently and on each de-energization completes a circuit at armature 157 extending over armature 181 and its back contract, winding of relay C, arma-.
  • Relay C being slow to release remains energized throughout the train of impulses and at armature 165 opens a point in the rotary magnet circuit, at armature 166 short-circuits relays I and D and at armature 167 completes a circuit for the upper winding of relay I which accordingly operates but without effect at this time.
  • Relay H is not 0 erated unless the test wiper 185 picks up attery indicating that the line is idle and if this does not occur, when relay G again de-energizes owing to the opening of its circuit at springs 185 it again completes a circuit for the rotary magnet B so that the wipers are advanced a further step.
  • relay H When an idle line-is reached, relay H is operated from battery picked up by the test wiper and at armatures 172 and 177 switches the speaking leads through to wipers 183 and 184, at armature 173 connects earth to test wiper 185, at armature 17 4: locks itself up over its lower winding, at armature 175 opens the rotary magnet circuit and prepares a circuit for relay BP and at armature including relays I and D is now placed across- 176 disconnects the vertical magnet.
  • the arrangement whereby relay-"I is maintainedsaturated also reduces the impedance when relays I and D- are subsequently re-inserted in the 100 and this overcomes any tendency for the line relay of the distant switch to de-energize momentarily and give a false impulse.
  • the connection. has been completely set up and the wanted party replies, the current flow over the speaking conductors is reversed at the final selector and is then in such a direction as to operate relay D.
  • This relay accordingly at armature 169 opens the circuit of the'supervisory lamp OSI-I' and completes the circuit of relay DR which at armature 153 opens a further point. in the operators hold circuit and at armatures 154: and 155 reverses the connections of relay A to conductors 151 and 152 thus repeating back the supervisory signal.
  • relay D is again de-energized and connects up the lamp CSH' the prolonged lighting of which accordingly indicates that the called party is being held.
  • relay A de-ener zes and releases relay AB at armature 15 and at armature 156 opens the loop to the succeedingswitches so as to effecttheir release 1n the usual manner.
  • Relay AB opens the 01rcuit of relay B and when relay B has deenergized the circuit of the release magnet is completed as follows: earth, armature 157 and its back contact, armature 181 and its back contact, winding of relay C, armature 164 and its back contact, off-normal springs 186, winding of magnet Z'to battery.
  • the release magnet operates to restore the switch to normal and relay C is also energized though without any particular effect in this case.
  • relay I is de-energiz'ed and a circuit is then completed as follows: battery, lower winding of relay BP, back contact and armature 178, front contact and armature159, back contact and armature 168, front contact and armature 175, front contact and armature 163 to earth.
  • Relay BP is a two-step relay and at this time operates only its light armature 179 thereby preparing a locking circuit for itself. On
  • relay I again energizes thereby at armature 168 removing the short-circuit fromthe upper winding of relay BP which thereupon energizes fully and at armature. 178 prepares a circuit for .relay BF.
  • relay I When relay I next de-energizes the circuit previously traced will be extended to relay BF which will accordingly energ'me with the results previously described.
  • Relay I will now continue to operate in synchronism with the busy flash pulses and relay BF will pulse similarly thereby repeating the busy signal back to the calling party.
  • relay B is now energized while relay AB is (lo-energized, the battery connection to the lower speaking conductor is repeated back over front contact and armature 164 and normally closed springs controlled by armature 160 to lead 152 to hold up the preceding switches.
  • this represents a final selector or connector switch, that is to say one which is adapted to connect with a wanted line and does not perform any hunting operation.
  • This switch is assumed to be accessible over selectors modified according to the invention, for instance, as shown in any of Figs. 1-4.
  • linerelay is operated and at armature 207 completes a circuit for the lower winding of relay B.
  • Relay B upon operating, at armature 208 removes the normal battery connection from test lead 203 and replaces it by earth, at armature 209 prepares circuits for relays E, F and H and at armature 210 disconnects the release magnet Z and prepares the circuit of the vertical magnet V.
  • relay A de-energizes intermit-' tently in accordance therewith and on each de-energization completes a circuit from earth, armature 207 and its back contact, armature 210 and its front contact, armature 219 and its back contact, armature 231 and its back contact, lower winding of relay 0 to battery and in parallel therewith armature 223 and its back contact. winding of vertical magnet V to battery.
  • the vertical magnet is operated in the usual manner to raise wipers 233235 to the required level. and relay C is also operated and since at armature 212 it short-circuits its upper winding it is rendered slow to release and thus remains energized throughout the train of impulses.
  • relay C de-energizes and a circuit is then completed as follows: earth, armature 209 and its front contact, armature- 228 and its back contact, back contact and armature 212, off-normal springs 237, windingof relay E to battery.
  • Relay E upon energizing at this time, at armature 222 completes a locking circuit for itself independent of relay C and at armature 223 connects up the rotary magnet R in place of the vertical ma gnet V.
  • relay G When the final series of impulses is transmitted, relay G is energized over the same circuit as before and impulses are transmitted to the rotary magnet R which accordingly steps the wipers into engagement with the contacts associated with the wanted line.
  • the upper winding of relay G is new connected to test wiper 235 so that if busy contacts are passed over during the rotary movement relay G will be energized. This however produces no detrimental effect since the busy circuit is held open at armature 213 and the impulsing circuit is maintained intact at armature 214.
  • relay A de-energizes and accordingly during the next earth period of the busy flash
  • relay B de-energizes also.
  • the release magnet circuit is completed from earth, armature 207 and its back contact, armature 210 and its back contact, off-normal springs 236, release magnet Z to battery and in parallel thereto, lower winding of relay G to battery.
  • Relay G is accordingly maintained energized until the switch has reached normal position and at armature 216 removes the battery connection indicating the idle condition so as to ensure that the switch shall not be again taken into use until it has fully restored.
  • Relay H moreover at armatures 225 and 232 connects up wipers 233 and 234, at armature 226 closes a circuit for giving ringing tone to the calling party, at armature 227 prepares a circuit for the supervisory lamp, at armature 228 applies direct earth to test wiper 235 and opens the circuit of relay E, at armature 230 connects earth to the lower winding of the back bridge relay D and at armature 231 opens the impulsing circuit to prevent any further operation of the rotary magnet in case the subscriber should dial again.
  • Back bridge relay D is now operated over the called partys loop and at armatures 205 and 206 reverses the connections of line relay A to conductors 201 and 202 for metering or supervisory purposes.
  • relay D again de-energizes and reverses the current flow over the speaking conductors back to'its original direction and at armature 204 completes a C11- cuit for the supervisory lamp the prolonged lighting of which indicates that the called party is being held because the calling party has not hung up.
  • release takes place in the manner previously described, relay G being operated in parallel with the release magnet to ensure that the switch is not marked as selectable until it has properly restored to' ment is preferable in some circumstances for.
  • Fig. 6 also differs slightly from Fig. 3 as regards the holding circuit of relay H in that the B relay contact has been included in the circuit of the holding winding instead of that of the energizing winding.
  • relay MD is again operated when relay B energizes and locks up dependent upon relay D.
  • relay D operates and opens the circuit of relay MD whereupon it releases but no metering circuit is completed.
  • relay A de-energizes and opens the circuit of relay AB which (ls-energizes also after a short interval.
  • Relay AB opens the circuit of relay B but since relay B is slow to release there is a short time durin which relay AB is (lo-energized and relay energized.
  • Relay H it will be noted is dependent upon relay B. Accordingly a circuit is now completed from earth, back contact and armature 251, back contact and armature 252, armature 253 and its front contact to the metering lead 254. This circuit is maintained until armature 253' restores on the de-energization of relay H following the release of relay B.
  • Relay C is en- I ergized during the release operation as before and applies earth to the test conductor for guard ng purposes.
  • relay MD will be maintained energized and accordingly will not commence. to release until relay B has fallen away at which time the circuit of relay H will be opened so that the metering circuit cannot be completed.
  • Fig. 7 is similar to Fig. 6 except that metering is effected by the connection of booster battery to the test conductor instead of by earth potential to aseparatemeteringlead and that the H relay contacts'in the metering circuit are unnecessary as the test conductor extends over contacts of relay B.
  • the operation is substantially similar, booster battery being connected up during the time that relay B is falling away.
  • relay MD will not commence to release until relay B is de-energized and thus it will not be possible for the metering circuit to be completed.
  • said switch responsive to said seizure for disconnecting said one pole of battery from said conductor and for connecting the opposite pole of battery to said conductor to mark said switch busy with a busy potential.
  • an automatic hunting switch having an incoming test conductor, means in said switch for normally connecting one pole of battery to said test conductor to apply an idle potential, means for seizing said switch if idle, means in said switch responsive to. said seizure for discomnecting said one pole of battery from said conductor and for connecting the opposite pole of battery to said conductor to mark said switch busy with a busy potential, a test wiper for said switch, means for operating said switch and wiper to extend a connection, means for disconnecting said opposite pole of battery from said conductor responsive to the establishment of said connection, and means for connecting the opposite pole of battery to said conductor by way of said test wiper to maintain said switch busy and in operated position.
  • an automatic switch having line wipers and'a test wiper, trunk lines each having line contacts and test contacts accessible to said line and test wipers, means for operating said wipers over said contacts to hunt for an idle one of said trunk lines, a relay in said switch for connecting the talking conductors of said switch with said line wipers, means. in said switch for connecting one terminal of the winding of said relay to said test wiper during the hunting operation, and means in said switch for connecting a source of potential to the other terminal of said winding each time the test wiper engages a different test contact.
  • a busy relay operated 1n case said switch extends-a connection to a busy bus to indicate the busy condition thereoff means for releasing said switch
  • a calling line an automatic switch, means responsive to a call by the calling line for seizin said switch," a first relay in said switch aving two circuits, a slow relay in said switch energized responsive to-the seizure of said switch for energizing said firstrelay over the first of said circuits means controlled by the energization of sai first relay'for marking said switch busy, an operators position,
  • a telephone system as claimed in claim 1 in which off-normal contacts in said switch are included in the means for normally conmally connected to said idle potential, a test wiper in said switch having access to said test contacts, means for operating said switch and test wiper to connect with one of said trunk lines, and means in said switch for applying the opposite pole of battery to the test contact of the connected trunk line over said test wiper to mark such trunk line busy.
  • a telephone system as claimed in claim 1 including a test wiper in said switch, a driving magnet in said switch for operating said wiper in its hunting movement, and a circuit for operating said driving magnet completed independently of said test wiper as long as said test wiper encounters busy potentials during the hunting operation.
  • means for energizing the first ofsaid relays forconnectlng the opposite pole of battery to said conductor to apply a guardlng potential thereto only as long as said switch is in use means for deenergizing said first relay, means responsive thereto for releasing said switch and for energizing the second relay, means controlled by the energization of said second relay for applyin said guarding potential to said conductor uring the release of said switch, and means whereby the energization of either of said relays disconnects said idle potential from said conductor.
  • a telephone system as claimed in claim 4 including a magnet for driving the switch in its hunting operation and a second relay for connecting said source to said other terminal of said winding each time the test wiper engages a different test contact, an energizing circuit for said second relay, and means controlled by said magnet for intermittently closing said circuit on each operation of said magnet.
  • a telephone system as claimed in claim 4 including a magnet for driving the switch in its hunting operation and a second relay for connectin said source to said other terminal of said wlnding each time the test wiper engages a different test contact, an energizing circuit for said second relay, means controlled by said magnet for intermittently closing said circuit on each operation of said magnet, an energizing circuit for said magnet, and means controlled b each energization of said second relay for opening said ma net circuit.
  • an energizing circuit for said second relay means controlled by said magnet for intermittently closing said circuit on each operaenergization of said secondrela for opening said magnet circuit, a set 0 springs in said switch, means for operatin said springs in case said wipers are operate beyond said contacts when all said trunk. lines are busy, and a locking circuit for said second relay completed responsive to the operation of said springs for preventing further operation of said wipers.
  • a driving magnet in said switch for controllin the hunting operation including a driving magnet in said switch for controllin the hunting operation, a driving circuit for operatmg said magnet, means for energizing said relay over a circuit including said test wiper, said .ergized responsive to the seizure of said switch for energizing the'said first relay over the first of said circuits, means controlled by the energization of said first relay for marking said switch busy automatic switches, an automatic subscriber s line, means responsive to a call by the calling subscriber for o crating said switch and automatic switc es to complete a connection to said automatic subscribers line, a third relay in said switch, a loop circuit including both talking con- .ductors of said switch for energizing said third relay when a connection is extended to said automatic subscribers line over said automatic switches, an operators position, means for operating said" switch to extend the connection from the calling line to said operators position, means responsive to the calling subscriber replacing his receiver for deenergizing said slow rel

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
  • Relay Circuits (AREA)
US390155A 1928-09-05 1929-09-03 Telephone system Expired - Lifetime US1823665A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB25483/28A GB322242A (en) 1928-09-05 1928-09-05 Improvements in or relating to telephone systems

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US1823665A true US1823665A (en) 1931-09-15

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Application Number Title Priority Date Filing Date
US390155A Expired - Lifetime US1823665A (en) 1928-09-05 1929-09-03 Telephone system

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US (1) US1823665A (fr)
FR (1) FR680124A (fr)
GB (1) GB322242A (fr)

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FR680124A (fr) 1930-04-25
GB322242A (en) 1929-12-05

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