Patent GB-264154-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1927-01-03
Abstract: 264,154. Reserve Holding Co., (Assignees of Nelson, M. L.). Jan. 6, 1926, [Convention date]. Automatic exchange systems. - In a system employing register-controllers of the code-translating type, a timing-device releases the apparatus after say 30 seconds if no digit is received, but a second timing- device brings about release after a shorter interval, say 10 seconds, in case of delay in dialling a second or subsequent digit. In the latter case the connection, so far as it may have been set up, is released and the call is routed to an operator. The first digit operates an A-digit switch, Fig. 2, to select a register-controller, Figs. 3-6; the second and third digits are recorded on a Strowgertype office register OR, Fig. 5, and subsequent digits up to a maximum of five on registers DR1 - - DR5, Fig. 6. The fifth register DR5 is provided to deal with calls to partylines and also with 5-digit calls to single lines, since it is assumed that in all exchanges in the area the 10th levels of certain 2nd selectors (those reached by a first digit 6, 7, 8, 9 or 0) lead to 3rd selectors instead of connectors, so as to provide a capacity of more than 10,000 lines. The switch-through of the connection at the relay-group TC, Fig. 1, and the release of the registercontroller normallv take place as soon as a digit has been sent out by the register DR5, but in the case of a 4-digit call, switch-through. &c. is effected by a timing-device 5 seconds after the register DR4 has been set, or as soon thereafter as a digit has been sent out under control of the register DR4. If, however, the record on the registers DR1, DR2 shows that the call is to a 5-digit single line, switch-through &c. is prevented until the fifth digit has been received and retransmitted. The timing-devices are constructed as shown at TD, Fig. 5. When a magnet 405 is energized it swings a ratchet-sector 403 within reach of pins 407, 408 on a rotating shaft, so that the sector is stepped round and after predetermined intervals operates contacts 410, 411 by means of cams 402, 401. When the magnet 405 is de-energized the sector is withdrawn from a detent 409 and is restored by gravity to its normal position. The subscribers' dials are lettered as shown in Fig. 7. The letters I and O are avoided as initials of exchange names, and a first digit consisting of a single impulse, due for example to a switch-hook vibration, is arranged to produce a selfcancelling effect. To prevent errors due to confusion on the part of the subscriber, certain sets of terminals of the office-register OR are multipled together so that the dialling of the figure 1 may produce the same effect as the dialling of the letter I (= 4) and the figure 0 the same effect as the letter O (= 6). Thus for example the 11th, 14th, 41st and 44th sets of terminals are all multipled together. The sending switch of the registercontroller, shown at the right of Fig. 4, comprises a relay 306 which is energized when a sending machine passes its pick-up position, removes a short-circuit from impulse contacts, and locks itself to a group of stopwires 1 - - 0 one of which has been grounded by a register. Cam 331 - - 340 successively disconnect the the stop-wires from the relay 306 so that the relay is unlocked after the proper number of impulses has been sent. Specifications 194,580 and 200.484 are referred to. A-digit switch, Fig. 2. When this is seized by the switch SS, Fig. 1, relay 104 is energized and dialling tone is sent back over 137, 113, 37, 13. The A-digit is repeated by relay 8 over 37 to the vertical magnet 118, and the switch operates in known manner to select an idle registercontroller. Springs 111, 112 are shifted onlv at the second vertical step, so that after a single impulse the circuit of the rotary relay 106 is not closed and the release magnet 108 is energized. If no idle outlet is available, 11th step springs 138, 170 are shifted, so that the switching relay 107 is opencircuited and a tone signal sent back. Registering subsequent digits. Relay 304, Fig. 4, is energized over 37<1>. The B and C digits are repeated over 37, 36<1>, 241 to the vertical and rotary magnets 420, 419, Fig. 5, of the office register OR, and subsequent digits to the registers DR1 - DR5,Fig. 6, the switch SE, Fig. 3, being advanced after each digit by an impulse from relays 201, 202. Sending operations. In the third position of switch SE, ground is connected over 247, 212, 354, wiper 221 of switch SE', 270, wiper 426 of the office register, to one of the ten stop-wires indicated by numbers in circles. A branch of the same circuit extends over wiper 220 to a circuit 251, 321, so that when the impulse machine, Fig. 4, next passes its pick-up position relay 306 is energized and locks itself to the grounded stop-wire. Relay 306 opens a short-circuit 317 across impulse-springs controlled by the cam 341. After the desired number of impulses have been generated in the circuit 35<1>, 38<1> the grounded stopwire is disconnected from relay 306 by the corresponding cam of the series 331 - - 340. The relapse of relay 306 again short-circuits the impulse-springs and de-energizes the back-stroke magnet 217, Fig. 3, to advance the switch SE<1> to its second position, in which the second digit is similarly sent under control of the second wiper of the office register, and so on. If a digit is to be skipped, connection is made over the frame I.D.F. to a wire 260 to step the switch SE<1> at once to the next position. After the code digits have been sent, the pick-up circuit 251, 321 is grounded over circuits 279 - - 281 connected to off-normal contacts of the registers DR1 - - DR5, so that the thousands digit cannot be sent until the hundreds register is off-normal, the hundreds digit until the ten register is off-normal, the tens and units digits until the units register is off-normal, and the party-line digit until the setting of the party-line register DR5 is completed. Release of A-digit switch and register-controller. In its tenth position, when all digits have been sent, the switch SR<1> grounds the wire 250 to energize relay 302, Fig. 4, which locks itself to wire 37<1>, cuts a resistance 301 into the outgoing circuit 35<1>, 38<1>, and grounds the circuit 36<1>, 37 to energize relay 10, Fig. 1, which locks itself and switches the talking-circuit through. Relays 8, 9, 11 successively relapse and a circuit is momentarily closed for magnet 30 to step the switch SS to its next terminals. Relay 104, Fig. 2, relapses and energizes the release magnet 108. The ungrounding of wire 37<1> removes a shortcircuit from relay 303, Fig. 4, which energizes in series with 304 and grounds circuit 269 through a low-resistance relay 305 to release the registers OR, DR1 &c. and the switch SE. The relay 305 keeps busy ground on the wire 37<1> while release is proceeding and de-energizes relay 304, which closes a restoring circuit for magnet 217 of the switch SE<1>. Call to a 4-digit non-party line. In this case no digit arrives for the register DR5, but the timer TD, Fig. 5, which is started, as soon as the register DR4 has been set, by the closure of circuit 405, 418, 252, 249, 230, 203, prepares after 5 seconds a circuit for relay 507, Fig. 6, which is energized over 430, 410, 281, 504 provided that a short-circuit 321, 251 has been opened by the movement of the switch SE<1> to its 9th position. The relay 507 connects the grounded wire 278 to the circuit 250 of relay 302 to bring about the energization of the switching relay 10, Fig. 1. Call to a 5-digit non-party line (first number digit 6, 7, 8, 9 or 0, second digit 0). In this case relay 506, Fig. 6, is energized over the registers DR2, DR1, locks itself to the wire 37<1>, switches the wiper of register DR2 to the 0 stopwire, and opens the circuit of relay 507 to prevent a premature switch-through. Delay in dialling first digit. The timer TD<1>, Fig. 2, is set going as soon as the A-digit switch is seized, and if after 30 seconds its circuit has not been opened by the switching relay 107 it grounds the wire 37 to energize the switching relay 10, Fig. 1. Relays 51, 52, 41 are energized and the prolonged lighting of a. lamp 42 attracts an attendant. The circuit of the vertical magnet 68 is opened by the relay 10 so that the selector S will not be affected if the subscriber now starts dialling. Delay in dialling a subsequent digit; call routed to operator. The timer TD, Fig. 5, started after the receipt of each digit by the closure of circuit 405, 418, 252, 249, 230, 203, is restored as soon as the next digit arrives by the opening of this circuit at contact 203, but if 10 seconds elapses without a digit arriving it grounds the wire 258 to energize relay 215. This relay grounds the circuit 249, 252 (to keep the timer going even if the subscriber should now dial), grounds circuit 269 to release the registers OR, DR1 &c. (but not the switch SE), grounds circuit 260 to restore the switch SE<1>, energizes magnet 208 to ensure that the switch SE is off-normal, opens the circuit 35<1>, 38<1> at contact 222 to release the connection so far as it mav have been set up, and energizes relay 216. This relay locks itself. opens the incoming impulse circuit, and connects the wires 270 - - 273 to a set of terminals on the I.D.F. jumpered so as to determine the sending of three digits to route the call to an operator. After an interval the timer TD onens the circuit of relay 216, which takes ground off the circuit 249 to release TD and grounds the circuit 354 to start sending operations. After three digits have been sent, the circuit 250 is grounded over the fourth wiper of the office register to energize relay 302, which brings about the energization of the switching relay 10, Fig. 1. Modifications when no A-digit switch is used. In this case the jumper 418, Fig. 5, is cut, so that the timer TD does not start until off-normal contact 424 of the office regis