Patent GB-206578-A (GB)
Title: Improvements in telephone systems
Filed: 1922-08-08
Abstract: 206,578. Western Electric Co., Ltd., and Polinkowsky, L. Aug. 8, 1922. Automatic exchange systems; metering.-In a registering mechanism comprising a number of registering devices upon each of which a digit of the wanted line is recorded, a plurality of registering devices is provided for recording a particular digit, the particular registering device to be used being selected by a switch controlled over the calling line. In the system described, a calling line is connected in known manner to an idle register set, Figs. 1 and 2, an auxiliary register 102, Fg. 1, of which is set by the first digit to select one of a group of registers 203 - - 206, Fig. 2, upon which the second digit is then recorded. Subsequent digits are recorded on numerical registers 207 - - 210. The selectable registers 203 - - 206 are provided with two normal positions, and, according to the setting of the auxiliary register 102, either remain in the first normal position or advance to the second normal position before responding to the second digit. The contacts of the registers 203 - - 206 are connected to the left-hand side of an intermediate frame IF the bus-bars on the right-hand side of which are connected to a group of counting relays CRO, CRO<1>, &c. The contacts on the left-hand side of the frame IF are jumpered to the busbars on the right-hand side in a manner corresponding to the routing number which must be transmitted to steer the call to the destination indicated by the setting of the register 102 and the selected register 203 - - 206. The contacts of the numerical registers 207 - - 210 are connected to the bus-bars on the frame IF leading to the counting relays, in accordance with any desired scheme of numbering or translation. The registers 207 - - 210 are provided with two brushes c, d, the contacts engaged by which are connected to the frame bus-bars in accordance with different numbering schemes, the particular brushes to be used in extending a connection being determined by the setting of the selected register 203 - - 206, the contacts engaged by the brush c of which are jumpered to bus-bars 265 extending either to the brush d or the brush c of the thousands register 207. The register set is also provided with means whereby if the first digit is O or if the selected register 203 - - 206 is set to a position corresponding to a non-existing exchange, the calling line is extended to a supervisory operator. Other features of the system which form the subject-matter of the claims of a divided application are as follows : (1) The selected register 203 - - 206 according to its setting may control the operation of a first group selector only over its brush d, thereby causing the call to be extended over three group-selecting stages, or it may control the operation of first and second group selectors over its brushes band d, respectively, and cause the call to be extended over four group selecting stages, (2) a call may be routed to operators' positions reached from certain levels of the first or fourth group selectors or to a call indicator at an operator's position, (3) means are associated with the register set for the prevention of metering on certain classes of calls, for example, on calls requiring only three group-selecting stages and calls to operators' positions. The eventual capacity of the network is one million lines and alternative connections are described for use when the system is working at its full capacity and calls to all subscribers are made over four group-selecting stages. Alternative connections are also described for use when the capacity of the network is so small that no call requires more than three group selecting stages. Setting of registers by the dialling impulses. The calling line is extended in known manner to a cord circuit which seizes an idle register set, the stepping relay 112 Fig. 1, of which is energized (over a circuit 140, 213d, cL, aL, dE) and closes a circuit for a relay 114 which drives the sequence switch 100 into its second position in which dialling tone from an interrupter 119 is transmitted to the calling party. The line relay 111 is also energized when the register set is seized, and completes a circuit for a slow-acting relay 115, which energizes a relay 116, which in turn closes a locking circut 111a, 117h, 116c, for the relay 115. On the first de-energizaton of the line relay 111 when the calling party dials the first digit of the wanted line designation, relays 121, 122 are energized, the relay 122 closing a circuit for the stepping magnet 102 of the auxiliary register, over the brush d of a controlling switch 101 in its normal position. Subsequent interruptions in the line circuit effect corresponding de-energizations of the relay 122, thereby causing the auxiliary register to be stepped round to a position corresponding to the first digit, in which position one of the group of registers 203 - - 206, Fig. 2, is selected over the brush arm d. The slow-release relay 121 remains energized during the impulse series and energizes the controlling switch stepping magnet 101, the retraction of which on the cessation of the impulse series drives the controlling switch into its first position in which the impulse circuit is extended over the brushes d of the controlling switch 101 and the auxiliary register 102 to the selected register 203 - - 206. Assuming the first digit was an even one, say 2, the selected register 206 is then stepped round to a position corresponding to the second impulse series, on the cessation of which the relapse of the slowrelease relay 121 drives the controlling switch 101 as before to its second position in which the impulse circuit is extended to the thousand register 207. If, however, the first digit is an odd one, say 3, when the controlling switch 101 moves to its first position on the cessation of the first impulse series, a series circuit is immediately completed over the brush c of the auxiliary register 102 for a relay 146 and the stepping magnet of the selected exchange register 206 which thereby advances to its first position where its circuit is again completed over the off-normal arc contacts engaged by its brush a, and the register continues to be advanced until the normal position in the second half-bank is reached. The register 206 is then further advanced by the second series of impulses, in the manner before described, to select contacts in the second half bank, and the impulse circuit is extended to the thousands register 207. The setting of the thousands, hundreds, tens and units registers 207 - - 210 takes place in a manner similar to the setting of the exchange register 206, the relay 122 transmitting impulses thereto in turn, whiles the relay 131 causes the control switch 101 to advance a step after each impulse series to connect up the succeeding register. Controlling-operations : discrimination between calls requiring three or four group-selecting stages. In a " mixed '' network the plain dottedline connections from contact CK to contact 116b and from battery to contact aN are removed, but the connection from contact dK to contact aD is closed at X. On the cessation of the second series of impulses when the controlling switch 101 moves to its second position, the relay 114 is energized over the brush b of the switch 101, and closes a circuit for a relay 130 which remains locked up over its left-hand winding in positions, 2 to 14 of the sequence switch 100, which is thereupon driven to its fourth position. For all calls. necessitating the setting of the numerical registers 207 - - 210, the contacts of the selectable register 203 - - 206 engaged by their brushes c are connected over the frame 1F to contacts 265 extending over the brush c or d of the register 206 to a relay 131, which is locked energized on the sequence switch 100 passing to position 4. If the selected register 203 - - 206 is set to a position corresponding to a call which requires. only three group-selecting stages for its extension to a connector, the contact engaged by its brush b is connected over the frame 1F to a contact 234 extending to a discriminating relay 132, which is energized when the sequence switch passes to its fourth position, over a circuit aN, cN, 234, aC, bC, A. Relay 132 energizes a relay 133, which closes a locking circuit for relay 132 and energizes the sequence switch 100 (over a circuit 100, cO, bO, 133e), causing it to be. driven through its fourth position in which the first group selector would otherwise have been controlled. The sequence switch passes to position 6 in which the fundamental circuit 140, 112, 213d, 113, cL. dK, 133e, to the first group selector is closed, the outstepping relay 112 responding in this circuit and completing a circuit dD, 112c, aM, 130a, for an upper counting relay, say CR9<1>, connected over the frame 1F to the contact engaged by the brush d of the selected register, say 206. When the relay 112 is short-circuited in the usual manner upon the first step of the trip spindle of the first group selector, it removes at contact c a short-circuit across the lower counting relay CR9, which energizes in series with the upper relay CR9' and closes a circuit for the preceding upper relay. At the next short-circuit of the relay 112, the preceding lower relay locks up in series with the preceding upper relay and energizes the next preceding upper relay. This operation continues, a pair of counting relays locking up at each step of the trip spindle until a number of steps corresponding to the setting of the register 206 has been taken, when a relay 213 energizes in series with the locking circuit of the last pair of relays CRO, CRO<1>, and at its contact d opens the fundamental circuit. The relay CRO completes a circuit CROC, 243d, 114b, aB, for the switch 100 which moves to its eighth position, opening the locking circuits of the counting relays and t