Patent GB-373650-A (GB)
IPC: H04L25/04
Filed: 1931-02-17
Abstract: 373,650. Telegraph exchange systems. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Feb. 17, 1931, No. 5067. Convention date, May 9, 1930. [Class 40 (iii).] In a telegraph exchange system with automatic switching apparatus for establishing a connection, the groups of current impulses constituting the telegraph signals are passed through a correcting repeating system, located between the calling and called subscribers, and byepassed or cut-out by switching means when the selecting impulses are being transmitted. Establishment of connection to the called subscriber. To call his exchange, the subscriber TS moves the contact s from the false position of rest shown and reverses the energization of a relay ER which operates its contact er and effects the operation of a relay X and subsequently a relay R to effect the operation of the magnet DV of the preselector VW. When the lines leading to an idle line sector LW have been found, test relay T operates and at contacts t3, t4 switches through the lines a, b and effects the transmission of current over the b -wire to operate a relay ES which, through its contact es, energizes the receiving relay E to produce a clear signal and to set into operation the motor of the calling subscriber. The subsequent dialling impulses operate the contact a1 of a relay A and the first and second series are applied to the vertical magnet H and the rotary magnet D respectively. If the desired connecting line is free, test relay P operates, and at contacts p1, p2 switches over the calling line to the repeating correcting apparatus, Fig. 4. The subsequent selecting impulses are transmitted to a relay E1, Fig. 4, whose contact i<1>, repeats them over the solid rings EK1, SK1 of a repeating distributer to a sending relay S2 whose contact s2 retransmits them over the a wire to a further selector or exchange ZA to establish the connection to the preselector VW<1> of the called subscriber TS<1>. Over the c<1> wire, a relay I<1> and the test relay T<1> are energized in series, and at contacts t<1>3, t<1>4 the through connection is prepared. The relay ES<1> of the called exchange is energized and at contact es<1> effects the operation of the receiving relay E<1> which switches in the telegraph apparatus of the subscriber TS<1>, operating the contact s<1> thereby reversing the contact er<1> to energize the relays Xl, R<1>. At the contact i<1>1 a circuit is prepared for the rotary magnet DN<1> of a return signalling apparatus AN<1> which may be of the type described in Specifications 342,479 or 347,744. The contact z<1> which may be actuated as described in Specification 350,508 effects the intermittent energization of the rotary magnet DN<1> to step forward the arms d<1>1, d<1>2 so that groups of current impulses corresponding to the name and town or exchange of the called subscriber are transmitted over the arm d<1>2, wire b<1>, Fig. 5, and b wire, Fig. 3, to a receiving relay E2, Fig. 4. The initial impulse is arranged to reverse the contact e2 and to energize a start magnet EM2 which releases a brush EB2 to rotate over segments 1 .. 5, through which the signal impulses are applied to storing relays R21 .. R25. A short time after the commencement of the rotation of the brush EB2, a cam N2 closes a contact n2 effecting the operation of a relay SH2 and of the start magnet SM2 of the retransmitting distributer. The impulse applied by the contact sh2 and the impulses stored by the relays R21 .. R25 are passed, during the rotation of the brush SB2, to a transmitting relay from which they are retransmitted by the contact s1 over the b wire to the receiving relays ES, E of the calling exchange and sub. scriber TS respectively. The first and last impulses of the final signal of the return signalling apparatus are arranged to be of opposite polarity so that over the armatures of the relays R21, R25, a relay H, associated with the correcting apparatus, is operated. Telegraph transmission from calling to called subscriber and vice versa. The operation of the transmitting contact s in accord with the groups of impulses is arranged so that a start impulse is applied at the beginning of each group to the relay E1, which, over the closed contact h4, energizes the start magnet EM1 of the distributer brush EB1. The current impulses are applied during the rotation of the brush to storing relays R11 .. R15. The contact n1, closed by the cam N1, effects the transmission of a start impulse from the relay SH1 to the relay S2 and the energization of the release magnet SM1 which is associated with a brush SB1 acting during rotation to retransmit the stored impulses to the relay S2. The start impulse and the signal impulses are passed bythe contact s2 over the wire a, Figs. 4 and 5, to the relays ES<1>, E<1> of the exchange and of the called subscriber respectively. The telegraph transmission from the called subscriber operates the contact er<1>, and the impulses pass over contact t<1>3 and the arm d<1>2, stationary on its final contact, to the wire b<1>, and to the calling subscriber as described for the impulse groups of the return signal. Release. The calling subscriber breaks the connection by replacing the contact s, effecting the release of the relays X, R, T, Fig. 2, and the consequent return of the preselector to its initial position. Relay C Fig. 3, is released, and subsequently the relays P, Fig. 3, and H, Fig. 4, fall off. At the contacts p1, p2 the correcting apparatus is switched off, and the selector of the exchange ZA is stepped to normal. The relays I<1> and T<1>, Fig. 5, are released and the magnet DN<1>, energized over the contact i<1>2, rotates the arms d<1>1, d<1>2 to their initial position. Relays ES<1>, El fall off, and by the stopping of the called subscriber's apparatus, the reversal of the contact s<1> effects the release of the relays X<1>, R<1>. The called subscriber releases the connection by throwing over the contact s<1>, which reverses the contact er<1>, releasing the relays X', R<1>, and the relay ES of the calling subscriber. At the contact es, the contact s is reversed, and the release of the connection is completed as described above.