Patent GB-193980-A (GB)
Abstract: 193,980. Pollak, J. E., (Siemens & Halske Akt.-Ges.). Dec. 5, 1921. Automatic and semi-automatic exchange systems.-The lines of certain subscribers of a manual exchange are provided with impulse senders and terminate directly at an operator's position and also in a pre-selector having access to a numerical switch over which the subscriber sets up the call.. The pre-selector may operate when the subscriber removes his receiver, or may be started when the operator depresses a key associated with the calling line or inserts the calling plug in a special jack. The clearing signal may be given by the re-operation of the calling signal. Three systems are described. In that shown in Figs. 2, 2<A>, a manual line h4 is connected over switches IVW<1>, IIVW<1>, IGW, to a distant exchange by inserting the calling plug in a jack corresponding to the wanted exchange, whereas an automatic subscriber s4, after insertion of the cord plugs in jacks AK2, HK2, is connected by switches IVW, IIVW to a repeated Ue, by which the subscriber has access to the same, groupselectors as the operator. In a modified system, a single plug cord is used and the operator depresses a key corresponding to the desired exchange. In this system, each automatic line has a switch near its answering jack which is depressed by the operator to set in action the preselector of that line. In the third system, shown in Figs. 4, 4<A>, the lines of automatic subscribers are provided with jacks for incoming calls only, and the junctions to a distant exchange are divided into two groups of different numerical significance, calls set up by an operator at the outgoing exchange being extended over the third level, say, of the selector IGW, to a B-operator at the distant exchange and thence through an intermediate selector ZW to a second selector IIGW, whereas calls set up by an automatic subscriber pass over the fourth level, say, of selector IGW direct to a second selector IIGW. Call from manual line h4, Fig. 2. (First system.) The insertion of the calling plug VSTp in a jack corresponding to the wanted exchange causes a switch PW associated with an impulsesender JW to find the trunk taken into use. Trunks corresponding to the same exchange are grouped, and wires for each group are connected in inverse order with the terminals of the sender JW, which is stepped round until it reaches the terminal of the wanted group without sending impulses, and is then further stepped on until it reaches a normal position, an impulse being sent over the trunk for each of these steps to operate the group selector. The insertion of plug VStp in jack VK2 causes relay An to energize, the rotary magnet D3 of switch PW, which rotates until relay P energizes over circuit 9, 4, R3, 3. Relay P energizes magnet D5 of pre-selector IVW<1> which rotates until it finds an idle second preselector, when the test relay T3 energizes over 17, 18, T3, c, R2(I), 20, R2(II). Relay R2 energizes magnet D6 of pre-selector IIVW<1> which rotates until it finds an idle group-selector IGW, when the test relay T5 energizes over 13, 14, 21, T3(II), R2(I), 23, T5, c, V3, C1, and locks up over contact 27, disconnecting winding R2(II). The relay P also energizes magnet D4 of the impulse-sender JW, which rotates until relay P1 energizes over wipers 32, 35, the latter engaging one of the groups of contacts 34 corresponding to the wanted exchange. If, or when, an idle groupselector has been found, relay Y is energized over a circuit 45, Y, 44, 43, T4(I), 411, b-lead, 41, 40, and energizes a relay J over an off-normal contact 48 of sender JW. Relay J sends an impulse over wiper 52 and the a-lead to relay A1 of the group-selector and also energizes magnet D4, which moves the sender JW one step and shortcircuits relay J. Relay J and magnet D4 energize alternately, until sender JW reaches a normal position, when wiper 49 disconnects relay J, short-circuits relay Y, and energizes relay T4, which disconnects switch PW and the impulsesender and extends the holding circuit of relays T3, T5 to contact 3 of jack VK2. At the groupselector, the selecting-impulses are repeated by relay A1 to the vertical magnet H through a relay V3, which, at the end of the impulses, closes the circuit of the rotary magnet D10. When an idle junction to the wanted exchange is found, relays P2, Tr3 energize over a circuit P2(I), A1(II), 64, c1 Tr3, but the resistance of the circuit is such that relay A1 does not energize. Relay Tr3 closes a circuit over the b-wire of the junction to the distant exchange to energize relays HSR, SR1, and light lamp BSL. The insertion of plug VStp in the jack of the wanted line energizes relays SR2, BR, HR, PR, thus connecting up the ring- ing-generator GEN. A relay LR1 is intermittently energized over circuit LR1, DR, 87, 86, 185 and by short circuiting the high-resistance winding I of relay Tr3 energizes relay A1, which in turn short-circuits winding II of relay C1, thus energizing relay R3, Fig. 2, which short-circuits a resistance 92 to flash the clearing lamp SL2, indicating that ringing is in progress. When the called subscriber answers, his line relay AR4 disconnects the low-resistance winding of relay TR4, thereby de-energizing the differential relay SR2, which energizes the self-locking relay AB to disconnect the ringing relay PR. When the called party replaces his receiver, relay AR4 connects up winding II of relay TR4, thus energizing relay SR2, which closes a circuit over 81<1>, 81, 86, 87, DR, for relay LR1, which, as before, energizes in succession relays A1, R3 to light the clearing lamp SL2. When the A-operator removes plug VStp the selectors are released, and the clearing-lamp BSL at the second exchange lights over 78, 71 until the B-operator removes plug VStp. Call from automatic line s4, Fig. 2. (First system.) When the subscriber removes his receiver, relay AR2 lights lamp AL2. The operator inserts an answering plug in jack AK2, and, if the. subscriber wishes to set up the call himself, she inserts the calling plug in jack HK2 individual to the calling line. The closure of contact 111 operates the subscriber's pre-selector IVW to find an idle second pre-selector IIVW which connects the calling line to a repeater Ve associated with one of the group-selectors accessible to the pre-selectors IIVW<1>. The test relay T2 energizes over relay C3, and resistance 132 at the group selector. The impulse relay A energizes relay V1 which short-circuits relay C3 and switches the clead through. Selecting impulses are repeated by the relay A and operate the group-selector &c. as previously described. When the calling party hangs up, relays A, VI open contacts 121, 124, 134, thus releasing the group-selector and preselectors, the pre-selector IVW on reaching normal lighting both the clearing lamps over normal contact 119. Second system. The operator's cord terminates at one end in a plug and at the other in a pre-selector which acts like the pre-selector IVW<1> Fig. 2, to find a second pre-selector and group-selector. The contacts of the impulsesender are connected to a row of exchange keys, one of which is depressed by the operator; otherwise the operation is similar to that shown in Fig. 2, except that no provision is necessary to prevent the transmission of impulses before a group-selector has been found. The clearing signal is controlled from the group-selector over a special circuit, including the fourth wipers of the pre-selectors. If an automatic subscriber wishes to set up his own call, the operator starts his preselector by operating a switch near his answering jack. On ;the release of the connection, the calling lamp is lit through a resistance, thus giving a dull light so as to distinguish a clearing signal from a call. Alternatively, the clearing signal could be given by flashing the call lamp. Third system in which calls set up by an operator and an automatic subscriber to the same exchange pass over different levels of the first selector. Call from manual line. This is extended by the operator, as in Fig. 2, to the group-selector IGW and is extended over its third level, say, to a B-operator's position at the distant exchange, the test relay P2 energizing in series with a relay C2 which causes a service selector DW to find the incoming trunk, whereupon the test-relay P3 energizes in series with a relay T5 which extends the B-operator's set to the incoming trunk. Relay C2 also energizes a magnet D8 to rotate an intermediate selector ZW to find an idle second selector, whereupon the test relay P4 energizes in series with relays F, C5. The second selector operates, under control of the B-operator, in the same way as the first selector to find an idle line selector LW, the test relay P5 energizing over a circuit P5, A2(I), 201, C4(II). Relay C4 moves the control switch of the line selector into its second position, in which the tens impulses are repeated by relay A3 to the lifting magnet H through the relay V5, which, when the impulses cease, moves the control switch into its third position in which the rotary magnet D9 is operated by the units impulses. In the fourth position of the control switch, the line is tested by relay P6, and in the fifth position relay L connects up ringing-current. When the called party answers, relays Y moves the switch into its sixth position or conversation position, and energizes a locking relay O. When the called party hangs up, relay Y at 720 short-circuits the high-resistance winding of relay C4, thereby strengthening the current in the test circuit to energize relay A2, which in turn short-circuits the upper winding of relay C5, thus energizing relay F, which short-circuits the upper winding of relay C2 to energize relay A1. As before, relay A1 shortcircuits winding II of relay C1 to energize relay R3, which short-circuits resistance 92 to light the lamp SL2. The connection