US2660620A - Automatic telephone system - Google Patents

Description

4, 1953 F. P, GOHOREL AUTOMATIC TELEPHONE SYSTEM 2 Sheets-Sheet 1 Filed Sept. 30, 1950 el 53 h C hr n- 013 U 0x3 Inventor FERNAND P. GOHOREL )5 A iiorney Patented Nov. 24, 1953 2,66 0 AUTOMATIC TELEPHONE SYSTEM Remand, Pierre .Gohorel, Anton France,.assignor to International Standard Electric .C .orporation, 'New York, N. Y., a corporation of Delaware Applicationiseptember 30, 1950, SerialNo. 187,718

Claims priority, application France October 3, 1949 2 Claims.

In the patent application filed on June 14, 1950, Serial No. 168,072, by Martinus den Hertog et al., for a Selection system for electrical circuits or equipments, a group selector has been described which comprises, for each connector, in addition to the control magnet of the connector, an additional relay. The details of the selector are shown in the application filed by A. J. Montchausse on January 26, 1950, Serial No. 140,735.

The object of the present invention is, by means of special circuit arrangements, to eliminatethe additional connector relay and only to provide a single electro-magnet, in order to ensure the functions of association of the selector to the common control circuit and thus a connection of the input of the selector tothe outgoing lines, and to improve the operative conditions.

One of the characteristics of the invention consists in the fact that the input wires of each selector are connected to the common control circuit and that the input wire which is employed to produce the connection is connected to said common control circuit through a winding of the control magnet of the connection.

Another characteristic of the invention con sists in the fact that the winding of the control magnet of the connection, inserted in one of the input-wires of theselector in the common control circuit, is provided in such a way that it does'not cause the attractionof the armature of said control magnet, when the selector is seized, the intensity of the current passing through it not having sufiicient value, but it causes the attraction of said armature only-when an outgoing line of the selector fulfilling the required conditions, has been found by the common control circuit, means being provided 'then to modifythe intensity of the current in said winding.

Another characteristic of the invention consists in the fact that between the register and the common control circuit, mutual control means are provided such that the control of'the connection of the selector to the chosen line.

said control being eiiected by-the common control circuit, can only be effected if the register has cut ofiall the circuits which, atthe moment of the connection to the outgoing line, would be capable of causing a false order.

Another characteristic of the invention consistsin the fact that a single test 'wire -is provid edfor each outgoingiline of a selector, saidwire being employed for electronic hunting, andfor the second test made with direct current.

limitative example,

This latter arrangement has the particular advantage of engaging the chosen line with respect to an electronic finder as soon as the sec- ,ond test has started, while its busy condition is given, in selectors of the type described in the above mentioned application, only after the complete operation of the selector and the energisetion in the next selector of the relay which operates at the time that said selector is seized. The time during which a double test is possible is thus considerably reduced, which has the eftfzeci of accelerating selection to a very great ex- Another characteristic of the invention consists in the fact that means are provided so that the busy condition of the chosen line is maintained by the common control circuit until thisbusy condition is given by the selector itself at the time of-the connection.

The essential idea of the invention, as also various other characteristics, will become clear from the following description given as a nonwith reference to the at tached drawing, in which only those elements are shown which are necessary for an understanding of the invention. The arrangements shown correspond to a case of 'a group selector, but they are applicable to the case of a line selector.

Fig. 'l is a circuit diagram of a portion of a selecting-system embodying the invention showing the register-andportions :of two selectors; and

Fig. 2 is "a circuit diagram of another portion of the selecting system, showing other selectors .and a common control circuit.

In Fig. 1 of the drawing are shown the elements of register En seized for the selections and establishment of the connection, said register comprising an electronic comparator COE, and. Fig. 2, which should be placed at the right of Fig. 1, shows the elements of a selector S4 associated with a common control circuit Or which comprises an electronic finder CHE. The Common control circuit Or .is associated with other selectors similar to S4.

The contacts HB '(Fig. 2) are associated with one of ;the horizontal connection bars of the selector, which is .a multiswitch of the cross-bar type, and operated by saidbar, and the contacts H are associated with the clutch control magnet H of said bar.

The line of the calling station PA must be put in communication with the line of the wanted station RD, through the selectors S2, S3 and S4. While the communication is being established,

the register En (Fig. 1) is connected, through a finder SI, successively to the selectors S2, S3 and S4 in order to check the routing, in accordance, with the general operation described in the patent application, Serial No. 168,072, referred to above and in the application, Serial No. 171,341, filed June 30, 1950, by the same inventor.

It will be been routed and that the register is connected to the inputs (13, b3, 03, d3, of selector S4. The relay Br (Fig. l) of En is pulled up. The follow".- ing circuit is completed: earth, make contact B2 of relay Br, winding of Chr, wires 'ol, b2, and b3 (Fig. 2), back contact HBI, right-hand winding of the clutch control magnet H of the selector, winding of relay Bor and battery. The resistance of relay Chr, Bor, and of magnet H are such that relays Chr and Bor are energised in series but the magnet H cannot operate its armature. By its make contact BoZ, the relay Bo'r completes the circuit of relay Bar which is energised through the back contacts HrZ of the relay Hr, and Col of the relay Cor. By its contact Ed, the relay B01 prepares the firing circuit of the tubes VA to V0. By its contact Chl (Fig. 1), relay Chr completes the impulse transmitting circuit of amplifier Ai (Fig. 2) of electronic finder CHE to the electronic comparator COE (Fig. l) of register En. These impulses are sent in predetermined time units and characterise each line and each group scanned as has been explained in the application, Serial No. 168,072, referred to above. When a line is free, an earth potential is applied to the input point F (Fig. 2) in the electronic finder CHE of the test wire of said line. This test potential is applied through resistance R2, back contact H'1, back contact HBE and the wire 94. The contacts H1 and HB'B are respectively associated with thebrake magnet E (Fig. 1) of the scanned selector and with the connecting bar of said selector.

When a free line in the wanted group is scanned, an impulse situated in time Pdu, for example, is received in the amplifier A1 of the electronic finder CHE and sent through: back contact H2, back contact I-IB3, wire d3, d2 (Fig. 1), dl, back contact Old and make contact Chi,

assumed that selectors S2, S3 have to the electronic comparator COE. Said com- 1 parator moreover, receives the comparison impulse Pdu through the rectifier Rd. The coincidence of the impulse received from CHE and the comparison impulse causes the transmission of said impulse Pdu in the amplifier A2 and the transformer T as has been explained in the patent application, Serial No. 168,072, referred to above.

The impulse received in transformer T is transmitted on the one hand to a discharge tube VS of COE, and, on the other hand, through the circuit: right hand winding T, wire 0 5, c2, 03 (Fig. 2) back contact HBZ, to a series of tubes VA, VB, VC and VD of the electronic finder CHE.

The tube VS is fired, contacts B1, and 0702 being closed, and the relay Sir is energised. Through its contact Sil, the relay Sir forms the circuit of relay Otr which is energised. The tube VD (Fig. 2) of CHE is fired and applies to the point M a sufficient potential to block the input of amplifier Al so that no other characteristic impulse can be sent by said amplifier. Moreover, certain of the tubes VA, VB, VC are also fired in accordance with the time unit in which the impulse from the register is received, that is to say, in accordance with the line scanned in the same time unit. Tubes VA, VB and VC being fired (1 tube VA, 1 tube VB, 1 tube VC) cause the energisation of the routing relays 0a, Ob, 00 as has been explained in the above mentioned patent application; the routing relays comprise a certain number of contacts, the combination of which makes possible the energisation of a magnet such as Va (Vu') which corresponds to the line scanned, and found free. If, for example, a magnet vu is energised, it closes its contacts Vul and Vu2. The contact Vul closes the energisation circuit for the relay Hr in series with Vu and in parallel with the resistance r3 through make contact Oal or Obl. Contact Vu2 causes the following test circuit: earth, resistance RZ, back contact H1, back contact HBG, wire g4, make contact VuZ, point X where test wires of the outgoing lines of the selector are reassembled, contact Hr3 closed; relay Cor, back contact I-lB-l, wire a3, a2 (Fig. 1), al, back contact Pei of relay Per, make contact Ot3 of relay Otr, upper winding of relay T1 and battery. The relay Tr is energised and shunts its upper high resistance winding through its lower low resistance winding in series with the relay Dtr, through the make contact Ti of Tr. If two selectors simultaneously seized the same line, two relays Tr of the registers temporarily associated would be energised, but as soon as their make contact Tl was closed, the number of ampere turns in each relay shunted by each other, would not be sufficient to maintain both of them pulled up; as the release of the two relays Tr does not take place simultaneously because a very slight deviation of operation always results in the manufacture of two identical relays, the first to fall back opens its contact Tl, the other is held in the operative position. As soon as the relay Tr is energised, the wire 94 is brought to a negative potential of the feed battery (-48 v.) owing to the fact of the relatively high value of the re sistance RZ in relation to that of the relays Dtr, Tr, and Cor. The result is that the point F (Fig. 2) of input in CHE and consequently the point FM are set at such a negative potential that allthe electronic finders of the other common control circuits serving the selected line will not send impulses when they explore said line, which is immediately made busy.

When the relay Dtr (Fig. 1) of the register En is energised in series with the low resistance winding of the relay Tr, the relay Cor (Fig.2) of the common control circuit Or is also energised. By its contact Col, the relay Cor opens the circuit of the relay Bor which falls back, and

which, by the opening of its contact 30!, causes the extinction of the tubes Va, Vb, Vc, Vd. Through its contact C02, relay Cor closes a holding circuit of the relay Hr of which the energisation circuit is opened by the release of the relays 0a or Ob. Through its contact C03, the

relay Cor holds the amplifier Al blocked (at least for the scanning impulses) after the extinction of the tube VD.

In the register En (Fig. 1), the relay Dir,-

which is pulled up, opens through its contact Dtl the circuit of relay Otr which is released. Through the make contact Dt2 of relay Dtr and the back contact Otl of relay Otr, energisation circuit of the relay Okr is completed. After the release of relay Otr and the opening of its make contact -Ot3, the circuit of relays Tr and Dtr is completed by the make contact Dt3 of Dtr. Through its make contact 0103 the relay Okr applies a direct earth to the wire bl, b2, b3 (Fig.

5 2) and, through its contact Okl (Fig. 1), applies the wire dl to earth through the upper low resistance winding of relay Per; through its back contact OkE, it opens the circuit of the tube VS and of the relay Sir which is released.

Owing to the application of direct earth through 0R3 to the wire bl, b2, b3, the intensity in the circuit of the right hand winding of magnet H (Fig. 2) of the selector is strongly increased and sufficiently so that said magnet H operates its armature causing the engagement of the bar of the selector with the operating bar of the servo-magnet. Through its contact HI, the magnet H cuts off resistance R2 from the wire e3 and substitutes for it the left hand winding of magnet H, thus completing the holding circuit for said magnet H on the battery through the resistance RI of selector S3. Through its contact H2, the magnet H disconnects wire (13 from electronic finder CHE and returns it to the relay Gr which is thus placed in series with the relay Per. The resistances of relay Per and GT are provided in such a way that only the relay Gr is energised. Through its make contact GI, the relay Gr completes the circuit of relay Kr which is energised. The left hand high resistance winding of GT is then short circuited by the make contact G2 of the relay Gr and by the make contact K2 of the relay Kr; owing to this, the current circulating in the upper winding of the relay Per of En, in series with the right hand low resistance winding of Gr, is sufficient to cause the attraction of said relay Per (Fig. 1). By this circuit, the energisation of magnet H and of the relays Gr and Kr is thus controlled.

Through its back contact Pel, the relay Per opens the test circuit, that is to say, the circuit of relays T1 and Dtr which fall back. Through its back contact Pe2, relay Per opens the circuit of Olcr which falls back, if the relay Sir has already been released, that is to say, if its holding circuit, through its make contact OM and the make contact Si2 of the relay Sir, is open. When the relay Olcr has fallen back, the circuit of the upper winding of the relay Per is opened by the contact Olcl; however the relay Per is maintained operated on its lower winding by its make contact Pet and the make contact Did of the relay Dtr, as long as the relay Dtr has not re- H leased, in order to maintain the contact Pei open until the contact D753 of relay D'tr is open, so as to maintain a cut off on the wire al, a2, (13 during the time of operation of connection of the selector, which can only take place if said wire is open. The busy condition of the selected line is maintained by the contact K3 (Fig. 2) of the relay Kr which connects the winding of Cor to battery through a low resistance r4.

When the make contact Olcl (Fig. 1) of relay Okr is open at En, the relay Gr (Fig. 2) of 01' falls back and through its back contact G1 and the make contact K4 of the relay Kr completes the circuit of the servo-magnet SH which causes the operation of the connecting bars of the selectors. The operating bar of selector S4 is actuated which causes the connection of wires a3, b3, 03, 23 to the wires at, b4, 04, cit and the operation of contacts HBi, BB2, HBE, H134 which cut out connection of selector S4 to the common control circuit 01, of the contact H35 which, through resistance R, l, applies a negative potential of the battery to the wire e4 so as to maintain the seized line busy.

Finally, the servo-magnet SH opens through its contact Shl the circuit of relay Kr which falls back.

The common control circuit has thus returned to normal and the register is ready to proceed with the next selection.

Iclaim:

1. In an automatic telephone system a selector switch for setting up a connection between a calling and a called line, said selector switch being of the cross-bar type having input lines, output lines, normally open contact means for connecting said input lines with selected ones of said output lines, and normally closed additional contact means associated with said input lines and controlled by the operation of the switch horizontal connection bars, and a clutch control magnet for each of said connection bars, the combination comprising a control circuit connected to said input lines over said additional contact means, a register, means for connecting said control circuit over said input lines of said selector switch to said register, an electronic comparator in said register, means for setting said comparator to respond to an impulse at a predetermined time position identifying a group of lines of which a free line is to be selected, means in said control circuit for Sending impulses over said input lines at a plurality of different time positions representing a free line in the selected group, means in said register responsive to the operation of said comparator for sending an impulse at the time position corresponding to that of the first free line to said control circuit, means in said control circuit for registering the time position of the received impulse from said register, and means controlled by said registering means for operating said clutch control magnet so as to close the outgoing contacts to said first free line and simultaneously open said additional contacts so as to disconnect said control circuit.

2. In an automatic telephone system, the combination, as defined in claim 1, in which there are a plurality of sets of input lines, a set of additional, normally closed contacts, for connecting each set of input lines to the control circuit, and a clutch control magnet for each set of input lines, further comprising an energizing winding on each of said clutch control magnets, and means including a pair of additional contacts of the set associated with a magnet for connecting the energizing winding thereof in series between the associated input line and the control circuit.

FERNAND PIERRE GOHOREL.

No references cited.

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