US1556474A - Automatic switching system - Google Patents

Automatic switching system Download PDF

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US1556474A
US1556474A US653568A US65356823A US1556474A US 1556474 A US1556474 A US 1556474A US 653568 A US653568 A US 653568A US 65356823 A US65356823 A US 65356823A US 1556474 A US1556474 A US 1556474A
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relay
contact
contacts
circuit
magnet
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Barnay Antoine
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/42—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker

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  • the present invention relates in general to an automatic switching system of the kind generally known as a step by step system, employed particularl in telephony, but capable to be employe generally in any system of intercommunication either electrical or electromagnetic.
  • the main object of the inventlon is to produce a new and improved system of selec tion'whereby the operation of the selectors,
  • Another object of the invention is to employ only one type of switch, of simple mechanical construction, robust, having very little inertia, for the difi'erent series of I switches such as preselectors, finder switches and selectors.-
  • a further object of the invention is to pro vide an auxiliary organ individual to a selector or common to a number of selectors of the same category of very little inertia which is operated by the impulses of the calling device and which in turn directs the group hunting movement of theselector or selectors i
  • another object of the invention is to provide means for grouping the lines connected to the banks of the different switches in the mosteconomical manner according to the needs of the trafiic.
  • Fig. 1 is a diagram of the; different organs used to establish a connection.
  • Figs. 2, 3 and 4. are circuit diagrams of the'organs represented "in, Fig. 1 and should I diflerentconnections between i the auxillarv control switches and the selector switches.
  • Fig. 8 isanother circuit diagram in which the, control switches are common to acertaln number of selectors.
  • the organs employed to establish a con nectlon and represented in Fig. 1 consist of the calling subscribers'telephone P, a line and cut oil relay R, a finder switch A, a preselector B, a undreds selector D, a line selector E,the line and cut off relay of the called line R and the called 'subscribers telephone P.
  • the system represented is a three digit system, for a four digit system, there would be another selector, the thousand selector, similar to the selector D, introduced between the calling'line and the line selector E, for 5 digits two selectors between the calling line and the connector, and finally, for a two digit system the selector D would be omitted.
  • a finder switch A and a preselector B areshown but according to the trafiic to be handled it might be economical to use only one or the other of these two organs. I The progression of tliecall is. the same, excepting for the transmission mechanically and electrically of the impulses sent out by the calling device, as in the best known step by step systems.
  • the subscribers stations P and? may be one of anyof the well known types having a calling device which opens and closes the line circuit a number of times equal to the digit to be sent.
  • the line and cut off relays R are individual to each line, and each line is multipled on the banks of a group of finder switches and also on the banks of the line selectors which have access to the group of one hundred lines, in which is located the 'line considered.
  • the finder switch A' and the preselector B consist of agroup of relays and two rotary switches K and i of a group of relays and a rotar switch K similar to the rotary switches 1 and K
  • the switches represented at K K K and K are step by step rotary switches of the type in which the-wipers move in a forward direction only.
  • the bank For a 50 line rotary switch, the bank consistsof tliree rows of 50 contacts each and 3 double wipers, fora 100 line switch the bank consists of 6 rows of 50 contacts each and either six single wipers or 6 double wipers, and a relay associated with the wipers to select one of the two sets of wipers. This latter arrangement is preferable as it diminishes by half the rotation of the switch.
  • the bank For a 200 line switch the bank consists of 12 rows of 50 contacts each and 12 single wipers are used with a wiper choosing relay.- For the selectors, in all case'san extra row of contacts on the bank and an extra wiper are provided to control the rotation of the switch.
  • Each selector is provided with a set of off normal sprin s which are operated as soon as the wipers save their normal position.
  • the line finder A is a 100 line rotary switch having two sets of three double wipers
  • the preselector B is a 50 line rotary switch with 3 double wi ers
  • the selector D has two sets of t ree double wipers and an extra wiper with its associated row of bank contacts.
  • the control switches such as C, associated with the selectors are of the same general construction as the previously described rotary switch K K K and operates in the same manner. They are much smaller than.
  • the rotary switch K K K K and are provided with two or more rows of 11 contacts each, and have a set of 03 normal springs which are operated when the wipers leave their normal position.
  • the control switch C, Fig. 52, associated with the selector D is provided with two rows of 11; contacts each, arranged in such that the contacts occupying correspon ing positions in the two rows, are connected electrically by the wiper.
  • the Fig. 3 is the circuit diagram of the line selector E with its two associated control switches C and C and its rotary switch K These organs are similar to those of the hundreds selectors shown in Fig. 2; the only difference between the line selector and the hundreds selector is the arrangement of the circuits.
  • the Fig. 4 represents arotaryline selector, i. e. a selector which after being directed to a group of lines by two trains of impulses is capable to select and connect with an idle line in the group, the selection of an idle line in a group being automatic and each group of lines being determined and limited by the resistance of the cut 05 relay of the last line of the group which is less than that of the other cut off relays associated with the other lines of the same group.
  • the cut off relays such as R,, R and R of the lines, which are served by a rotary line selector, are provided with an extra terminal connected to the left hand end of the winding of the cut off relays.
  • the test wire is connected to this middle terminal when there is only one line, or to the middle contact of the last line when there are several lines listed under one number.
  • the test wire is connected to the end terminal on all the other lines of the group.
  • Fig. 5 is a diagram showing the connections between the control switch and the row of control contacts of a thousands or hundreds selector which has access to ten different groups of trunk lines and each group of trunk lines having ten trunks. Supposing that the selector is a hundreds selector; in this case the control wires for the 1st. and 2nd. hundreds, 3rd. and 4th. hundreds, 5th. and 6th. hundreds, 7th. and 8th. hundreds, 9th. and 0 hundreds, are connected together on the bank of the control switch.
  • control wires are connected to five series of 10 contacts on the row of control contacts in the bank of the rotary switch K, in such a way that when the digit 1 or 2 is dialled, the selector only rotates to find an idle line, when the digit- 3 or 4 is dialled, it rotates over ten contacts before beginning the trunk hunting movement and so on. For the digits 9 or 0, the selector rotates over 40 contacts before beginning the trunk hunting movement. The selection between the odd or even digit is obtained by a wiper selecting rela as will be described in the de tailed circuit description further on.
  • an ldle trunk in the'group may be selected by the automatic rotation of the wipers the control wire for the group being connected to the ten confacts of the control bank in the chosen group.
  • Fig. 6 is a diagram representing. an uneven grouping on a ten thousand selector in a multi-oflice telephone system. It is assumed that there are 60,000 subscribers lines in the system, distributed amongst six dif necessitate 750 trunks between the two ofiices in one group, this groupment may be obtained by employing secondary line switches each having a capacity of 50 trunks and the trunks from the selector banks in groups of 15. i If it were necessary to have only 650 or 700 trunks, the trunks from the selectors banks would be arranged in groups of 13 or 14.
  • trunk from the selector banks will be arranged in groups of 10.
  • t is not necessary to have any two groups alike, for example, in providing two rows of control 'contacts,10 groups of trunks each having a different numberof trunks may be obtained.
  • trunks there may be 50, 100, 150 or 200 trunks in a selector bank and these trunks may be arranged in any number of group between 1 and 10.
  • the traffic may be distributed in an entirely different way than in the oflice considered and an arrangement of the trunk groups entirely different would be moreeconomical;
  • Fig. 7 is a diagram showing the connections between the control switches and the control contacts of a line selector.
  • tens control switch 0 has five wires (one for two tens consecutive) connected to the first contact ofeach group of ten contacts in the row of control contacts of the bank of the rotary switch K the selection of the odd or even tens being obtained by ,a relay.
  • the units control switch G is connected by 9 wires (the first contact is not connected as it does not require the rotation of the selector) to the nine remaining contacts in each one of the 5 groups of tens control contacts.
  • the line selector has a capacity for 100 lines but its capacity may be doubled when it connects with subscribers having several lines listed under one number. In this case, a second row of control contacts on the bank of the rotary switch is necessary.
  • the calling line is extended to a selector (hundreds selector in a 3 digit sys tem, thousands selector in a 4 digit system, etc. by means of a finder switch or a preselector or the two organs acting together.
  • the control switch Responsive to the first train of impulses sentby the calling device, the control switch takes a position corresponding to the impulses received and places a battery potential on a control contact of the bank of the main rotary switch so as to stop the'latter on the first trunk of the group determined by the first train of impulses.
  • the main rotary switch does not wait until the end of the train of impulses before commenc in to operate. Assoon as the control switch reaches a'position that determines a movement, the main. rotary switch commences to operate and continues until the control wiper reaches the contact which is connected to the control switch. After reaching the aforementioned contact, the
  • the first'control switch directs the wipers to the tens group corresponding to the impulses received for the tens digit and the second, operated by the unit digit impulses directs the wipers on to the particular line of the tens group al-' ready chosen
  • the line selector selects an idle line in the group,- if-there is one, and in case all the lines are busy, gives a busy signal to the calling subscriber.
  • an idle line is identified by the presence of negative battery on the test wire, and a line tests busy if the negative is not connected to the test wire, therefore the so called dead lines i. e. the lines not in service give automati-j cally the busy test when an attempt is made to connect with them.
  • the subscriber at station P desires to establish a connection with the subscriber at station P, whose telephone number is 903.
  • the receiver is removed at station a circuit is completed for the relay 2, flour Md, contact 6, the line and the st" scribers station in series, the contact 7, the winding oi? relays 2 to battery.
  • Relay 2 is energized and a contact t places ground on the starting wire of the tinder switches by the contact 9; and at the contact 3 connects the low resistance winding oi" relay 5 to the test contacts of the line finder banks.
  • the relay 33 of the finder A is energized by the gIUUfiMl on the starting wire, over the circuit ground. contact 4, contact 9, contact 45, winding of relay 33 to battery.
  • Relay 33 energiz d closes the circuit of the rotary magnet over the path; ground, contact 41, contact 30, contact 21. contact 58, winding of the electro magnet 59 to battery.
  • ground is placed on the test wiper 10 in series with the winding of relay 16 in passing by the contact 25.
  • contact 36 ground is connected to test wiper 13 by way of the contact 18 and the winding of rela 24. lit the wipers of the finder switch are not on the set of contacts of the calling line.
  • the cut oti relay 5 opens the circuit of relay 2 at contact 7, removes the ground from the calling line contact 6, and at the front contact of armature 8, establishes its holding circuit, with its two windings in series.
  • the second *inding of relay 5 is oi high e ou h resistance to prevei e energization stop relay such as 16 or 24% of tinder switch and cons quently to another tinder switch to stopon line.
  • Y hen 1 ea ers circuit of the rotary magnet 59 at contact 21 and the wipers are stopped on the set of contacts of the calling line. Furthermore, the relay 16 prepares its holding circuit at contact 17, opens the circuit'ofrelay 24 at contact 18 and at contacts 22 and 23 connects the line wipers 11 and 12 to the contacts 50 and 52.
  • the pre selector K starts hunting for an idle hundred selector.
  • the relay 33 When the relay 33 energizes as has been explained, it closes the circuit of the rotary magnet 57 by the following path: ground, contacts 43, 38, 56, winding of the magnet 57, contact 119 to battery. At the same time at contact 40 the low resistance winding of relay 4:2 is connected to the test wiper 53.
  • the rotary magnet 57 operates as has been explained for the rotary magnet 59 to advance the wipers 53 to inclusive.
  • the wipers encounter the contacts of an idle hundreds selector, such as the selector D Fig. 2 which is identified by battery on the test wire, the relay a2 is energized over the circuit: battery, winding of the magnet 93 of the control switch C the first contacts of the two rows of contacts of the control switch, which are connected together by the wiper 100, contacts 80, 71, test contact of the bank of the preseleotor, test wiper 53, contact 40, upper Winding of relay 42, to ground.
  • Relay 42'011 energizing opens the circuit of the magnet 57 at contact 43 and. the wipers are stopped on the idle hundreds selector.
  • relay s9 the lower high resistance winding of relay s9, is connected to the test wiper and at contacts 49 and 51, the calling line is extended to the relay of the selector by Way of the wipers 54 and 55 and the contacts 112 and 11 i.
  • Relay 65 is energized in series with the calling line and by the contact 66 closes the circuit otrelay 68 to ground at contact at.
  • On energizing relay 68 replaces the fixturery potential on the test Wire at contact 71 by ground at contact 72, to complete the holding circuit of relay 42 in the preselector and to busy the hundreds selector to the other preselectors.
  • the finder switch and the preselector begin their operation at the same time. If the preselector finds an idle hundreds selector before the switch has found the calling line, the circuit as described for the relay 33 is opened contact i when relay 4&- is energized hu iinmed established by the contacts he winding of relay a slow relay do 0 s time that its cii 4-2 0' ates. When circuit of the relay 33 at either the contact 19 or the contact 28 and after an instance the slow relay 33 falls back.
  • the finder switch connects with the calling line before the preselectors finds an idle hundreds selector, if there are no other lines of the group in the calling position, when the relay 2 falls back at the energization of relay 5, groundwill be removed from the starting wire. But at the same time, the calling line has been extended to the contacts 50 and 52 by one of thestop relays 16 and 24 and the relay 33 remains energized in series with the calling line until the relay 42 operates. In any case, the relay 33 does notf-all backuntil the calling line is extended to an idle hundreds selector.
  • relay 68 prepares the impulse circuit for the magnet 98 of the control switch, at contacts 70 and 76 prepares the circuit of the magnet 115- and opens at contacts 69 and 74the release circuits'of the control switch C and the rotary switch K
  • the subscriber hears a special tone induced in the induction coil 109 that indicates that he can begin to dial his number, r
  • the calling subscriber will now operate his calling device dial in accordance with the first digit 9, of the called number as are-- sult of which nine interruptions will be produced in the circuit of his line and the line relay 65 of the selector D will be'deenergized nine times.
  • the relay 65 transmits an impulse of current to the magnet 98 of the control switch ,over a path which extends from ground by way of contacts 64, 67, the winding of relay 77, contact 7 3, the first contact in the first row ofcontacts in the bank, of the control switch, the wiper 100, the-first contact in the second row of contacts in the bank of the con.- trol switch, the winding of magnet 98 to battery.
  • the wiper 100 By the operation ofthe magnet 98, responsive to these impulses, the wiper 100 is advanced stepby step and is brought to rest on the -te'nthQQontact of the bank.
  • Relay 77 is ener'gizedin series with, the magnet 98 and since it is slow acting, it-holds its armaturejattracted during the series of impulses. Also the relay 68, on account of its slow action does" not fall back during the impulses.
  • the wiper 100 leaves its normal position and the circuit of the magnet 98 is opened at this point but a new circuit for the eight succeeding impulses has already been established by the relay 77 at the contact 81.
  • relay '77 short circuits the upper windingof relay .90 and at contact 82 opens a
  • the wiper 100 comes to rest on the I on the control wire that is connected to the control contacts in the bank of the rotary switch.
  • K thatv occupies the same positions as the trunklinesto the line selectors of the.
  • Relay 84 opens the circuit of the magnet 115 at the contact 89 before it hastimeto-operate.
  • the wiper 100 laces ground in serieswith the upper win ing of relay 90- on the same control wire as for the 1st. impulse but this winding is short circuited by relay 7 7 so no circuit changes'takes place and relay 84 remains energized.
  • the wiper 100 removes the ground from the control wire 101 and places it on the control wire 102.
  • This control wire is connected to the contacts on the control bank of the rotary switch K,- that occupies the same position as the trunks to the 3rd. and 4th. hundreds. lVhen the ground is removed from the Wire 101, relay 84 falls back and at contact 89 closes the circuit of the magnet 115.
  • This magnet operates in the same way as the magnets of the finder and preselector to advance the wipers 125 to 131 inclusive. The operation of the magnet 1.15 continues until the wiper 125 finds a grounded contact, which causes relay 84 to operate again and opens the circuit of the magnet 115 at contact 89.
  • the magnet 115 only advances, its wipers ten contacts, the wipers 125 to 131 inclusive are brought to rest in a very short time after the ninth impulse on the contacts of the first trunk connected to the ninth and zero hundreds.
  • test wiper 129 When the wipers are on an idle set of contacts, the test wiper 129 will find battery and the relay 61 is energized by the circuit; ground, contacts 78, 87, lower wind ing of relay 61, contact 91, test wiper 129, test contact, test conductor 134, resistance 204 (Fig. to battery.
  • the circuit of the magnet 115 is opened at contact 64 and the wipers brought to rest on the contacts of an idle line selector in the 9th. hundred.
  • the relay 145 energizes in series with the calling line and closes a circuit for the slow acting relay 153 to ground by way of the contacts 146 and182.
  • Relay 153 on energizing, causes a considerable number of circuit changes.
  • battery is removed from the test conductor and ground is placed on the same to complete the holding circuit o1 relay G1 in the hundreds selector and to busy the line selector to all other hundreds selectors.
  • the relay when the relay (35 falls back, it opens the circuit of relay 68, which on account 01 its slow action does not fall back but an instant later in order that the holding circuit furnished by relay. 153 or the line selector is assured hetore the contacts 72 and are opened.
  • relay 34 falls back and opens the circuit of the lower winding of relay 61, but this relay now has a holding circuit by the high resistance winding, the contact 62 and the grounded test conductor.
  • the magnet 115 would drive the wipers 125 to 131 inclusive on the first contact of the following group of trunks and as on this group of trunks the control contacts are not grounded.
  • relay 84 would fall back permitting the magnet 115 to drive the wipers to their normal position. ln this position, the contact 117 is opened and the circuit of the magnet 115 is opened as relay 7'? has fallen back.
  • the calling subscriber would receive the busy signal induced on the induction coil 110, as the ground for the line relay is fed through this coil by way of the contacts and 107. When the calling subscriber hangs up his receiver, the release would take place as will be described further on.
  • the relay 153 besides placing ground on the test conductor 13. as already explained, prepares the ini 'iulse circuits of the control switches C, and C, at contact 157; the ground at contact 159 is extended to the relay 161 by way of the wiper 207 and the first contacts in the two rows of contacts or" the tens control switch by way of contacts 159 and 186.
  • ground is'placed on the first row of contacts of the control switch C, and by the wiper 214 and the first contact of the second row of contacts of the said bank.
  • the ground is extended directly to the contacts 2. 4. 6. 8 and 10 of the first row of contacts of the tens control switch (1, and in series with the lower winding of relay 1% to the contacts 3, 5. 7, 9 and 11 of the same row of contacts.
  • the relay 161 energizes, it connects at the contact 163 the impulse cir cuit to the magnet 205 of the tens control switch and prepares its holding circuit at contact 164.
  • the calling subscriber now operates the dial of his calling device in accordance with the second figure 0 of the called number, as a result ten interruptions will be produced in the circuit of his line and relay. 145 will be deenergized 10 times. At each deenergiill) zation an impulse of current will be sent to the magnet 205 over a circuit which extends from ground by way of contacts 182,147,
  • Contact 209 is closed after the first step of the magnet 205 and a circuit is completed for the magnet 215 to ground by the contacts 216, 179, 209, 186 and 159.
  • the control wiper 224 of the rotary switch K when in normal position, is on a contact connected to the 2nd. and 3rd: contacts of the second row of contacts of the control switch C (see Figure 7) and since the wiper 207 places ground on these contacts as it passes them, after the first impulse, relay 177 is energized before the magnet 115 has time to operate and opens the circuit of the said magnet at contact 179. After the third impulse the ground on the 2nd. and 3rd.
  • the relay 196 connects up the wipers 225 to 227 inclusive as they have access to the even numbered groups of ten lines, and at contact 199 closes its holding circuit to ground by way of contact 159.
  • relay .148 When the relay .148 falls back it opens the holding circuit of relay 161 at contact 150 and relay 161 falls back also. In falling back relay 161 closes the impulse circuit to the magnet 210 of the unit control switch C by way of the contact 162.
  • the calling subscriber will now operate the dial of his calling device in accordance with the last digit 3 of the called number, as a result of which three interruptions will be produced in the calling subscribers line circuit and the line relay 145 will be deenergized three times.
  • the deenergization relay 145 transmits an impulse of current to the magnet 210 of the units control switch over a path which extends from ground by way of contacts 182. 147, winding of relay 148, contacts 157, 170, 162, the winding of the magnet 210 to battery.
  • the magnet 210 advances its wiper 214 one contact and at the end of the three impulses the wiper 214 will come to rest on the fourth contact of its bank. with the result that ground is placed on the control conductor 223, multiplied on the 3rd. contact in each of the ten groups of control contacts of the-bank of the rotary switch K, (see Fig. 7 V
  • relay 17 7 remains energized but when it leaves the second contact, relay 177 falls back and closes the circuit of the magnet 215.
  • Relay 17 7 is reenergized, opens the circuit of magnet 215 at contact 179 and the wipers come to rest on the third line of the tenth tens group of lines.
  • the relay 148 falls back after the last impulse, the circuit of relay 169 is closed by the path, ground, contacts 159. 186, 149, 180. 213, the upper winding of 169 to battery.-
  • Relay 169 establishes its holding circuit to ground. by way of contacts 159, 186-.
  • relays 161 and 189 are connected in series and by the contact 175, the test wiper 225 is connected at a point midway between the windings of relays 161 and 189, by way of the path, test wiper 225, contacts 198, 185, 167 and 175.
  • contact 170 the impulse circuit is opened.
  • the test contact is grounded, and this ground on the test wiper 225 short circuits relay 189 and energizes relay 161.
  • a locking circuit is established at contact 164 (this contact is adjusted to make before the others are operated) at contact 165, the connection of the test wiper to relay 161 is opened: at contact 167 the connection of the test wiper 225 to the relay 189 is opened and at the contact 166 ground is placed on the magnet by way of the circuit: ground, contacts 159, 186. 172 166, 217, 216 and the winding of magnet 215 to battery.
  • the magnet 215 operates and drives the wipers 224 to 230 inclusive to their normal position.
  • relay 189 is energized by its two windings in series but it only has enough ampere-turns to close the contact 187 without operating the others and on account of. the resistance of these two windings the cut 06 relay is not energized.
  • the test wiper 225 is connected to the upper low resistance winding of relay 189 and the relays 189 and 2341 are completely energized.
  • Relay 2341 removes the line line relay 232 from the line at contact 237, at contact 238 removes the ground from the called line and at contact 236 removes the short circuit from around its left winding.
  • the relay 2341 remains energized with its two windings in series. Returning to relay 189, a considerable number of circuit changes takes place when it is energized.
  • Relay 177 on Tallnoses-re ing back, closed the circuit of the ringing current on to the called line at contact 178 and the called subscribers bell is rung over the circuit: ground, the ringing generator 221, the ringing interrupter 220, 219, contacts 178, 193, 195, 202, the wiper 227, the line conductor 233, the subscriber s bell 2 13 and the condenser, 242 line conductor 232, line wiper 226, contacts 200, 1941, 191, the lower winding of relay 181 to battery.
  • a small capacity condenser is bridged across the contact 190 to permit a small part of the ringing current to pass out on the calling line each time that the called subscriber is rung.
  • the slow relay 181 is not energized by the ringing current, but when the called subscriber answers, a path for direct current is completed at the called subscribers station in series with the transmitter and receiver and the relay 181 is energized.
  • a holcing circuit is established at contact 181; at contacts 190 and 192, the calling line is extended to the battery teed relay 135.
  • Relay energizes in series with the called line and the called subscribers station.
  • the battery to the calling line is reversed at the contacts -141 and 138139 for supervisory purposes.
  • the relay 153 falls back. Tr" the calling subscriber replaces his receiver first, the relay 115 in falling back opens the circuit of relay 153 at contact 1 16 and, it itis the called subscriber who hangs up his receiver first, the relay 135 falls back and removes th ground on the winding of relay 153 at contact 136. ltelay 153 in falling back removes the ground on the test conductor 13 1 and relay 61 oi the hundreds selector, Fig. 2, is deenergized, and in falling baclr the connection of the calling line to relay 115 of the line selector is opened at contacts 111 and 113, and relay 1 15 falls back.
  • contact 159 opens and removes the ground from the holding circuits of relays 181, 189 and 196.
  • relay 189 restores the wipers are disconnected at contacts 194iand 195.
  • relay 181 falls back, ground is connected to the magnet 215 over the circuit; ground, contacts 182, 117, the winding of. relay 118, contacts 158, 217, 216, the winding of magnet 215 to battery.
  • relay 148 is energized and opens the test conductor at contact 152 thus causing the test line selector to test busy until the wipers are in normal position. An instant after the contact 217 is opened, relay 148 falls back and the lineselector is in position to receive another call.
  • relay 90- will energize in series with relay 84 when the relay '7 7 falls back after the last impulse over the circuit; round, contact 75 the upper winding 0 relay. 90,. 11th. contact of the first row of contacts, wiper 100, 11th. contact of the second row of contacts of the control switch G control conductor 105, 1st. contact of the 5th.lgroup of control contacts in the bank of ,control wiper 125, the winding of relay 84 to battery.
  • relay 90 establishes its holding circuit by its lower winding to ground at contact- 72 and at contact 63 when relay 61 is en-- ergized.
  • the wipers 126 to 128 inclusive are connected up at contacts 92, 94 and 96 and will be used in establishing the connection.
  • the selector proceeds to hunt an idle line selector as previously explained and will extend the calling line tothe samewhen it is found. Assume that the line selector F (Fig. 4) is used for the connection.
  • relay 258 When the relay 61 of the hundreds selector extends the lines to F (Fig. 4) relay 258 energizes inseries with the calling line and at contact 259 closes ground, on to relay 266.
  • ground bank As a further result of the energization of relay 266, ground bank.
  • the calling subscriber will now operate his calling device in accordance with the second digit 1 of the desired number. as a result of which, four interruptions will be produced in the circuit of his line, and the line 'relay 253 of the line selector l will be deenergized once, and one impulse of current will be sent to the magnet 326 over the circuit. ground, contacts 302, 260. the winding of relay 261, contacts 270, 315. 283. 276, the winding of magnet 326 to battery.
  • the magnet 326 operates and advances the wiper 328 on to the 2nd. contact of the Relay 261 energizes in series with the magnet 326 and at contact 263 completes the holding circuit of relay 274. and at contact 264 short circuits the upper winding of relay 318.
  • the contact 334 is closed and when relay 289 is energized after the last train of impulses. it closes the cir cuit of relay 282 over a path extending from ground by the contacts 272, 312, 262. 290, 334. the upper winding of relay 282 to battery.
  • Relay 282 on energizing. establishes its holding circuit at contact 285, to ground by way of the contacts 312 and 262.
  • the impulse circuit is opened at contact 283: at contact 284.
  • ground for the holding circuitof relay 274 is connected and by contacts 279, and 305. this ground is extended to the lower winding of relay 289 and to the relays 294 and 297 in series by way of contact 348.
  • the test wiper is'connec-ted to a point between the windings of relays 294 and 297. by the path. the test wiper 342, contacts 319. 313. 291. 236 and one side of the winding of re lay 294. It the first line of the three lines is busy. There is ground on the test contact in series with a relay such as relay 16 or 24 of the finder sw'itch (Fig. 2). it the line is calling or in series with a resistance such as resistance 363 if the line is busy by being called. In either case.
  • relay 294 is shunted by this resistance to such an extent that it is not energized when the test wiper is on the contact of a line having a resistance such as .360 and 361 connected in series with the winding of the cut off relav.
  • Relay 297 energizes by the ground on the test contact in series with the resistance such as 363 or the relay such as 16 or 24 (Fig. 2). As a result. ground is connected to the magnet 346 over the path ground. contacts 272; 312. 346 to battery. The magnet is energized and at contact 348. disconnects the test wiper 342 from the winding of relay 297v Relay 297 on deenergizing opens the circuit 296. 300.
  • relay 294 If the last line is busy, there is enough current through the winding of relay 294, on account of the comparatively low resistance of the winding of the cut ofi' relay 359, to cause the relay 294 to'operate at the same .time that relay 297 operates. As a result of the energization of relays 294 and 297, the circuit of relay 274 is closed over the path, ground, contacts 272, 312, 295, 298, lower winding of relay 274 to battery.
  • a locking circuit is established at contact 278; at contact 279, the ground extending to relays 289, 294 and 297 is removed; at contact 281, the busy signal is placed on the calling line, in series with the condenser 257.
  • a circuit for the magnet 346 is establishedat contact 280 by the path extending from ground by way of contacts 272, 312, 284, 280, 349, 347, the winding of magnet 346 to battery.
  • the magnet 346 operates and drives the wipers 338 to 344 to their normal position. In this position, contact 349 is opened and the wipers come to rest.
  • the calling subscriber on hearing the busy signal will hang up his receiver and the release takes place as will be described further on.
  • test wiper finds battery 111" series with the right low resistance winding of relay 357, and the relay 297 shunted by the battery in series with the low res stance winding of relay 357 is not energized but relay 294 is energized over the circuit, ground contacts 272, 312, 284, 279, 305, winding of relay 294, contacts 286, 291, 313, 319, test wiper 342, test wire 354 and the right hand winding of relay 357.
  • relay 294 the circuit of relay 310 is closed by a; path extending from ground, contacts 272, 312, 295, 299, the winding of relay 310 to battery.
  • Bela-3 .310 energiz es andv at contact 311 establishes a looking circuit to ground by way of" contact 272.
  • ground is removed from the banks of the control switches C and C and from the contacts 284, 285 and.295.
  • Relays 282, 294 and 297 fall back.
  • ground is placed on the winding of the cut off relay 357 over the path, ground, resistance 363, contacts 314, 319, test wiper 342, test wire 354 and the right handwinding of relay 357 to battery.
  • Relay 357 energizes in series with the resistance 363 and places its left hand winding and the resistance 360 in series with the right hand wind ing. Furthermore, the relay 357 removes the line relay (not shown) from the called line.
  • relay 310 Furthermore, at the energization of relay 310, the connection of the test wiper to the relay 294 is opened at contact 313; the impulse circuit is opened at contact 315 and the line wipers extended to the contacts 307 and 309 of the ring cut off relay 301 at contacts 316 and 317.
  • Relay 266 falls back, it the called subscriber hangs up first, relay 248 in falling. back removes the ground on relay 266 at contact 249 and if the calling subscriber hangs up his receiver first, the relay 256 falls back and opens the circuit of relay 266 at contact 259.
  • Relay 266 on falling back removes the ground on test conductor 247 at contact 269 and relay 61 in the hundreds selector D (Fig. 2) falls back and disconnects the line conductor at contacts 111 and 113.
  • Magnet 346 operates in series with the relay 261 and drives the wipers 338 to 344 totheir normal position. In the normal position contact 349 is opened and the wipers come to rest. During the operation of magnet 346, relay 261 remains energized and the connection of the test conductor to battery is opened at contact 265. As a result of which the line connector is busied to an further calls An instant after, the magne 346 ceases to operate relay 261 falls backand the line selector may be seized for another call.
  • each selector a chain relay such as 118, 118', and 118", which is energized as soon as the selector is taken.
  • all the chain relays of the'group are energized, and the circuit of the busying relay 120 is closed.
  • This relay on pulling up, places ground instead of main battery on the magnets of the preselectors.
  • the relay 42 of all the idle preseleetors in the group energize over the circuit: ground, contact 121, mag
  • a traffic meter 60 is provided for the line finders.
  • a line finder such as the line finder A finds a calling line
  • one of the relays 16 or 24 is energized at the same time as the relay 33 and the circuit of the meter is closed by the circuit: ground, oontact41, contact 20 (or 29), the meter 60, and main battery.
  • the relay 33 falls back the circuit of the meter 60 is opened and it falls back after having registered a call.
  • control switches instead of being individual each to a certain selector, are common to a number of selectors of the same category, the number of selectors associated with each control switch depending on the traffic to be handled and the control switches such as C, C and C, are inserted in the circuit of a selector, only during the time necessary for the operation of the selector, the other selectors which may be connected to the control switch in use being busied during this time, in order that other calls may be directed to other groups of selectors which are free to receive them.
  • the common control switch 0 is connected to its associated hundreds selectors circuit, one of which is represented at D by' the common conductors 434 to 442 inclusive, and the common control switches C" and C", connected to their associated line selectors circuit, one of which is represented at E by the common conductors 525 to 530 inclusive.
  • Relay 455 is operated before the relay 33 in the preselector falls back over the following circuit; negative battery, magnet 407 of the control switch C,, the first set of bank contacts of C,, short circuited by the wiper 408, in normal position, contact 419, the common conductor 437, contact 456, upper winding of relay 455, contact 472 established when the rotary switch K is in normal posi'ton, contact 459, test conductor 483, test contact, test wiper 53 ot the proselector B, Fig. 2, contact 40, upper winding of relay 42, to ground.
  • the calling line is connected to relay 429 by the contacts 453 and 454, at contact 450 a holding circuit for the lower winding is prepared, at contact 448, ground is placed on the 2nd, 4th, 6th, 8th and 10th contacts of the first row of contacts in the bank on the control switch C,; at contact 449, ground is placed on the 3rd, 5th, 7th, 9th and 11th contacts of the same bank in series with the lower winding of relay 464; at contact 444 the control wiper 476 is connected to the control relay 433 by way of the common conductor 442, at contact445 an operating circuit for the mag ing line and by the contact 415 closes the circuit of relay 431.
  • the calling subscriber will now operate his calling device in accordance with the first figure 7 of the called number and as a result of which seven interruptions are produced in the circuit of his line, and the relay 429'will be deenergized seven times.
  • 'relay 429 transmits an impulse of current to the magnet 407 of the control switch C over a circuit which extends from ground by way of the contact 416, winding of the slow relay 430, contacts 413, 414, winding of magnet 407 to battery.
  • the wiper 408 is rotated into contact with the 8th series of contacts and places ground on the control conductor 443.
  • Relay 430 energizes in series with the magnet 407 and remains in operated position during the series of impulses. Relay 431, also remains in operated position during the impulses.
  • the off normal contacts 403 to 405 inclusive are shifted and ground is extended to the magnet 475 of the rotary switch K, by way of the path, ground, contacts 405, 412, 423, 426, common conductor 441. contacts 445, 474, the winding of magnet. 475 to battery.
  • the magnet 475 operates and advances the wipers 47 6 to 482 inclusive.
  • the operating circuit of magnet 475 is opened at contact 426 and the wipers 476 to 482 inclusive come to rest; at contact 425, the circuit of relay 432 is closed (relay 430 restores an instant afterthe last impulse) by a path extending from ground by way of contacts 405, 412, 423, 425, 417, the winding of relay 432 to battery; and at contact 427 ground is connected to the test wiper 480 in series with the lower winding of relay 463 over the path, ground contact 427, contact 424' common conductor 439, contact 452, thelower winding of relay 463, contact 465 and the wiper 480.
  • test wiper 480 finds battery on the test contact and relay 463 is energized over the above described circuit. As a result of the energization of relay 463, numerous circuits changes are produced. At contat i.
  • relay 455 being slow acting remains in its operating position long enough, after its circuit is opened, to permit the relays in the following switch to energize and establish a holding circuit for the relay 463 by its upper winding.
  • relay 455' falls back, the connections with the common conductors 434 to 442 are opened and as a result, relays 429 and 433 fall back.
  • the wipers of the selector pass on to the contacts of the first line of the following group, but there is no ground on the corresponding control contact and the relay 433 has its circuit open and falls back, preventing the energization of the relay 465, and the wipers are rotated to their normal position, the electromagnet 475 being in the same circuit as previously described, which is opened at the normal position at contact 473.
  • the relay 433 by falling back closes at 428 and 424 the circuit of the secondary winding of the induction coil 409, which has a busy tone impressed upon its primary winding thus giving the busy signal to the calling line through the condenser 410.
  • Relay 536 energizes in series with the relay 463 of the selector D and there results numerous circuit changes.
  • the calling line is connected to the relay 489 by way of the common conductors 525 and 526, at contact 533, the control wiper 591 is connected to the common conductor 530; at contact 534, an operating circuit for magnet 586 is connected to the common conductor 529; at contact 535 relay 546 is connected to the common conductor 527; at contact 537 a holding circuit for relay 536 is prepared; at contact 538, a circuit for grounding test conductor 486 is'prepared and finally, at contact 539, ground is removed from the restoring circuit of magnet 586.
  • Relay 489 energizes in series with the calling line and by the contact 490 closes the circuit of the slow relay 504 to ground. Helay 504 on energizing, removes battery from the common conductor 528 at contact 497 and all of the line' selectors associated with the control switches C 2 and C" are busied. At contact 498, relay 504' places ground on the common wire 528 to hold the relays in the preceding switches energized.
  • relay 504 the impulse circuit for magnet 518 is prepared at contact 507; at contact 499, ground is placed on the first row of contacts of the control switch C" and on the first row of contacts of control switch C by way of the wiper 524 and the first contact of the second row of contacts of C", and at contacts 505 and 506 the restoring circuit of control switches C and C are opened.
  • relay 489 sends an impulse of current to magnet 518 over the circuit ground, contact 491, the winding of relay 493, contacts 507, 508, the winding of magnet 518 to battery.
  • the wiper 519 is rotated into contact with the 4th. contact and connects ground to the tens control conductor 532.
  • Relay 493 energizes in series with the magnet 518 and remains in operated position during the series of impulses.
  • Relay 504 also remains in operated position during the impulses.
  • ground is connected to the magnet 586 of the rotary switch K by the circuit, ground contacts 499, 515, 514, common conductor 529, contacts 534, 543, 585, the winding of magnet 586 to battery.
  • the magnet 586 operates and advances the wipers 591 to 594 inclusive.
  • relay 599 is energized over the circuit, ground, contact 499.
  • first contacts and wiper 524 of control switch C , first row of contacts wiper 519, 4th. contact in the second row of control switch C 2 tens control conductor 532, control wiper 591, contact 533, common conductor 530, the winding of relay 599 to battery.
  • relay 493 falls back after the last impulse, with relay 599 operated, the circuit of relay 546 is closed over the path ground, contacts 499, 511, 520, 513, 496. 535 the winding of relay 546 to battery.
  • Relay 546 on energizing establishes a locking circuit at contact 545 to ground by contact 562, the common conductor 528 and contact 498; at contact 543 the operating circuit of the magnet 586 is opened at contact 544, the
  • relay 489 is opened at contacts 540 and 541 t at contact 533 the circuit of relay 599 is opened.
  • relay 504 restores, the circuit of relay 510 is opened at contact 499 and at contacts 505 and 506 the restoring circuits for the switches and C, are closed to ground in series with the winding of relay 493 and contact 491.
  • Magnets 518 and 523 operate and advance their respective wipers 519 and 524 to normal po- At normal position, the circuit of magnet. 518 is opened at contact 516. and that of magnet 523 at contact During the restoration of wipers 519 and 524 relay 493 is energized and removes the battery from the common conductor 528 in order to busy all'of the associated line selectors while the control switches are restoring.
  • the control switches C and may now be employed to establish another connection.
  • the test wiper 592 finds ground 011 the test contact, relay 579 is shunted out and relay 567 is energized over the circuit, ground, test wiper 592, contacts 565. 542,580, 548, 570, the winding of relay 567 to battery.
  • Relay 567 on energizing closes a locking circuit at contact 569 to ground by way of contacts 547 and 563, opens the energizing circuit at contacts 570 and 565, and at contact 572 places a busy signal on the calling line by way of the path: battery, induction coil 587, contact 572, condenser 597 and the calling line.
  • the test wiper 592 finds battery in series with a low resistance winding of the out off relay such as the relay 596, the relay 567 is shunted and relay 579 is energized over the circuit, battery, right hand winding of relay 596, contact 595, test wiper 592, contacts 565, 542, the two windings of relav 579 in series, contact 563, to ground. With its two windings in series relay 579 only has enough ampere turns to close the contact 578. At contact 578 the upper high resistance winding is short cir-', cuited and relays 57 9 and 596 are fully energized. On being fully energized the cut off relay 596 places its left hand high resistance winding in series with its low resistance winding and the relay 579; Belay 579 remains in operated position When in series with the two windings of'relay 596.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
US653568A 1923-05-18 1923-07-24 Automatic switching system Expired - Lifetime US1556474A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR570941T 1923-05-18

Publications (1)

Publication Number Publication Date
US1556474A true US1556474A (en) 1925-10-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
US653568A Expired - Lifetime US1556474A (en) 1923-05-18 1923-07-24 Automatic switching system

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US (1) US1556474A (it)
DE (2) DE490255C (it)
FR (5) FR570941A (it)
GB (2) GB223985A (it)

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DE490255C (de) 1930-01-29
DE505408C (de) 1930-08-19
FR29482E (it) 1925-08-07
FR31705E (fr) 1927-06-10
FR31471E (fr) 1924-03-14
GB233339A (en) 1926-09-27
FR28111E (it) 1925-01-15
GB223985A (en) 1924-10-31
FR570941A (fr) 1924-05-09

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