Patent GB-233007-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04M19/00
Filed: 1924-01-01
Abstract: 233,007. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Jan. 1, 1924. Automatic and semi-automatic exchange systems; metering.-In an exchange network in which some distant calls are made over direct trunk lines while others are extended through an intermediate exchange, repeaters are only taken into use when a connection is extended through an intermediate exchange. These repeaters are located in the trunks between the intermediate and the wanted exchanges, one kind of repeater adapted to repeat impulses and the usual supervisory signals being used when the wanted exchange is another automatic exchange, and another simpler kind which is not required to repeat impulses being used when the wanted exchange is a manual exchange. Both types of repeater are adapted to repeat back a busy flash signal for use if the call originates at an operator's position. The invention is described as applied to a large network using register-controllers of the code-translating type. The dialled impulses are under all conditions sent to a register-controller, or suppressed at a relay group associated with the first exchange selector, the controlling impulses for setting the connecting switches being exclusively sent from the register-controller over a loop circuit from the register-controller including the two talking conductors, not only to switches at the originating exchange but also to switches at a distant exchange when such exchange is reached over direct junction lines and not through a repeater. The relay group at the first selector trunk effects the association therewith of an idle register controller and disconnects it when it is no longer required, controls the operation of the first exchange selector, operates supervisory signals in circumstances fully described in subsequent paragraphs of this abridgment, and supplies feeding battery to the. calling party. Other features of the system described are claimed in the divided Specifications 233,643, 235,818, 235,819, 236,497, and 238,477. The network described, comprises three automatic exchanges Nos. 1, 2 and 3, Fig. 1, manual exchanges Nos. 2 and 3 having " A " operators' positions, a mechanical tandem exchange MTE similar to that described in Specification 229,765, a manual exchange No. 1 provided with a call indicator position, and a manual exchange No. 4 having a trunk operator's position. Typical calls are described below, first in general with reference to the layout diagram, Fig. 1, and then where necessary in greater detail with reference to Figs. 2 to 12. Local automatic connection. A calling subscriber A, Fig. 1, at automatic exchange No. 1 is extended by a line switch LS to a relay group TR, associated with an idle exchange selector ES and with a secondary line switch SLS which selects an idle register-controller selector DS, which in response to the first exchange digit selects an idle register-controller. The registercontroller records the wanted number and sends out a single routing digit to step up the exchange selector ES, which then selects an idle local first selector S. The local first and second selectors S, S<1>, and connector FS select the wanted line A<1> in response to the numerical portion of the wanted number retransmitted by the registercontroller. Line switch LS, Fig. 2. This is a normal type switch. The line relay 6 closes a series circuit for stepping magnet 7 and switching relay 5, connects the test wiper 10 to a point between them, and completes an independent circuit for stepping magnet 7 over a normal position bank contact 10<a>. The switch thereupon moves out of its normal position and continues stepping in known manner until the ungrounded test terminal of an idle line 20 - - 23 is engaged, when the switching relay 5, being no longer short-circuited, responds and causes the calling loop to be extended to a line relay 25 in the relay group TR. Line relay 25 energizes release relay 27 and closes a first circuit for an impulse relay 48 over an impedance coil G and the right-hand winding of a polarized relay F, which however does not respond, its left-hand winding being energized in opposition over armature 75 of release relay 27. Secondary line switch SLS, Fig. 3, This also is a normal type switch. The line relay 25, Fig. 2, completes a series circuit 75, 94, 32, 93 for the switching relay 42 and the stepping magnet 31, Fig. 3, connects the test wiper 36 to a point between them, and closes a starting circuit 75, 94, 32, 38, 36, 29, over a normal contact, for the magnet 31, which steps round the switch until an idle register-controller selector DS is engaged, when the switching relay 42 energizes and connects the relay group TR to the switch DS. A second loop circuit 49, 56, 34, r, 35, 50, 51 is now closed for the impulse relay 48. Register-controller selector DS, Fig. 3. Relay 42 also closes a circuit from battery feed on the dial tone conductor DT, Fig. 3, over the calling loop and the lower winding of line relay 25, Fig. 2, for line relay 103, Fig. 3, which energizes the relay 105. On hearing the dial tone, the calling party dials the first exchange digit 8, causing eight relapses of the line relay 103. The wipers 113 - - 116 are stepped up to the eighth level and select a trunk 200 - - 203 to an idle registercontroller, in well-known manner. The off-normal spring pair 121<1> do not break until the second impulse is delivered to the vertical magnet, in order that if a single false preliminary impulse is sent the release magnet 119 is energized over springs 121. 121<1> on the relapse of the series relay 112, and absorbs the impulse : the first bank level is not used. Setting of register-controller, Figs. 4 to 6. The switching relay 129 of the selector DS, Fig. 3, extends the impulse receiving circuit over conductors 43, 131, 201 to relay 300, Fig. 5, and connects earth over holding conductor 200 to starting relay 209, Fig. 4, which earths conductor ISM to start an impulse motor arranged to drive the interrupter springs 374. Relay 209 also grounds a chain alarm conductor CAC over which a counting device is operated each time all the register-controllers are in use. Relay 129 also completes the impulse transmitting circuit 49, 56, 34, 134, 202, 309, 310, 311, 312, 315, 316, 317, 319, 320, 321, 203, 135, 35, 71 through the register-oontroller and the impulse relay 48, Fig. 2. The polarized relay 316, Fig. 4, does not respond in this circuit since its right-hand winding is energized in opposition over grounded lead 380. The second exchange digit 3 is repeated by the relay 300, Fig. 5, over circuit 301, 503, 305, 307 to the vertical magnet 304 of the exchange register BCR. During the digit, a relay 306, Fig. 4, in this circuit energizes relay 337, so that at the termination of the digit an impulse is sent to magnet 338, Fig. 5, to step the digit control switch MDS to its second position. The next exchange digit 3 is therefore delivered to the rotary magnet 342 and the switch MDS moved to its third position, after which the numerical digits are delivered in a similar manner to the magnets 343, 349, &c. of the thousands, hundreds, &c. registers DR1 - - DR4. Transmission of digits by register-controller. As soon as the switch MDS moves to its third position after the registration of the last exchange digit, it grounds the starting circuit 400, 401, 374, of a relay 373, Fig. 4, which is marginally adjusted and only operates armature 378, over which however both its windings energize in series, causing it to operate fully and at armature 377 connect the stepping magnet 214 of the sending switch SEN in the interrupter circuit. The sending switch SEN is now rotated, and having advanced one step energizes relay 378<1> over wiper 213. The relay 378 removes a shunt from the impulse contacts 321, so that at each subsequent step the magnet 214 opens the impulse circuit over the impulse relay 48, Fig. 2, in the trunk relay group TR, at armature 321. Since the call is a local one, the contacts on which the wipers 330 - - 335, Fig. 5, of the exchange register BCR rest, are so cross-connected at the frame IDF as to cause the transmission of one series of three impulses. The terminal 1 on the right-hand side is therefore jumpered to the busbar 3 on the left-hand side and the terminals 2 - - 6 on the right-hand side to the bus-bar DCO. A branch of the grounded circuit 400 extends also over wiper 365 of the switch SCS in its first position and wire 366 to the wiper 330 of the register BCR, and thence through the bus-bar 3 of the frame IDF to the third contact in the bank of the stop wiper 230, Fig. 4, of the sending switch SEN. When the wiper 230 reaches the grounded contact, i.e. when three impulses have been delivered to the relay 48, Fig. 2, stop relay 381 is energized and locks itself up, opening the circuit of the stepping magnet 214, completing a circuit 385, 384, 213 to return the switch SEN to normal, and closing a circuit over conductor 386 for magnet 387, Fig. 6, which steps the switch SCS to its second position where its circuit is opened by the relapse of relay 378', Fig. 4, on the switch SEN arriving at its normal position. The relays 378', 381 de-energize sluggishly to allow time for the hunting movement of the exchange selector before the interrupter circuit is recompleted for the magnet 214 and the transmission of the next digit commences. Since only one routing digit is required, the control switch SCS is automatically advanced to its seventh position over a circuit including grounded wire 400, wiper 365, the wipers 331 - - 335 in turn, bus-bar DCO, conductors 319, 390, and wiper 363. With the switch SCS in its seventh position, ground is connected over conductor 399 to the wiper of the thousands register DR1 and if, or as soon as, the setting of the hundreds register DR2 is begun, ground is connected over circuit 353, 401, 364 to the starting relay 373, Fig. 4, and the thousands dig