Patent GB-191325774-A (GB)
Title: Improved Method and Apparatus for Electric Code Impulse Signalling Systems.
IPC: H04Q5/06
Filed: 1913-11-11
Granted: 1914-07-16
Abstract: 25,774. Western Electric Co., [Woodward, F. T., (acting for Western Electric Co.)]. Nov. 11. Order apparatus.-Signals are transmitted by combinations of current impulses varying in strength, order and number, each combination being registered. In a system especially adapted for transmitting numbers for controlling the switches of an automatic telephone exchange, each combination, by means of a set of relays, serves to close one of a number of circuits, so causing a magnet to rock one of a set of levers, means being provided whereby a number of sets of levers are influenced in turn by a succession of signals. System of selection, Fig. 1. The impulsetransmitter 121 produces two kinds of impulses, a reduction and a complete break of the normal current flow in the lines 113, 114, twelve different combinations of two or three impulses being used for the numerals 0 to 9 and X, Y. The relay 117 releases its armature in response to either form of impulse, while relay 118 is only de-energized by a complete break. The sequence switch 139 of known construction has twentynine positions, the numbers adjacent to the various contacts 148, 149, &c. showing the position at which they are closed, those adjacent to the master contact 141 showing the stopping positions of the switch. When the subscriber removes his telephone, the relay 117 is energized over the line circuit from earth through contacts 145, 147, magnet 142, and battery 146 to earth, causing the sequence switch to move to its second position. The subscriber then sends the combination of impulses representing the first digit. The first impulse de-energizes the relay 117, closing the circuit of the relay 135 from battery 152 through sequence-switch contact 149, relay 135, contact 155 of relay 136, contact 156 of relay 117, to earth. If the impulse is a partial interruption, the working coil of relay 131 is energized from the battery 152 over the contact 149, winding 154, contacts 158, 159, 156, to earth, so moving relay armature from contact 161 to 162; if the impulse is a complete break this circuit will be broken at 159 by the de-energization of the relay 118, and contact 161 remains closed. At the end of the impulse the normal current re-energizes both relays 117, 118 and relays 135, 136 are energized over a hold-on circuit from the battery 152 through contact 149, relays 135, 136 and contact 157, to earth, relay 136 not having been previously energized owing to the short circuit over contacts 155, 156. The effect of this is to connect the contacts of the relays 117, 118 up to the selective relay 132 and switching relays 137, 138. The second impulse then energizes the relay 137 and either energizes or not the relay 132 according as it is a partial or complete interruption, and on its cessation the relay 138 is also energized. This closes at 171, 166 the circuits of the selective relays 133, 134, respectively; if the third impulse is a partial interruption, the relay 133 is energized from the battery 152 through contact 149, working winding 154 of relay 133, contacts 171, 168, 159, 156 to earth, while if it is a complete interruption relay 134 is energized from battery 152, through contact 149, relay 134, contacts 166, 163, 156 to earth. If the numeral is one of those represented by two impulses only, neither relay 133 nor 134 is energized. The selective relays 131-134 have hold-on windings 153 to retain their armatures when attracted. The energization of the relay 138 also closes the circuit of the sequence-switch magnet 142 from the battery 146 through magnet 142, contacts 151, 172, to earth, and the switch then moves from its second position to its sixth position. In its fourth position it closes at contact 174 the circuit of the magnet 21 corresponding to the number signalled, say the third, from battery 173 through contact 174, magnet 21 No. 3, contacts 175, 176, 177, 162 of the selective relays 131-134, to earth, so rocking one of a set of levers. The sequence-switch acts at such a rate that the third impulse has time to act before the contact 174 is closed. In its fifth position, the switch-contact 149 is opened, so de-energizing all the relays 131-134 and 135-138, and at the same time the contact 178 is closed, so energizing a magnet 22<a> causing the magnets 21 to act on a fresh set of levers. Each digit of the required number is separately recorded in a manner similar to the first, provision being made in the apparatus described for seven digits. If the subscriber hangs up his receiver at any time, the slow-release relay 119, which is not de-energized by the signalling current interruptions, releases its armature so closing the circuit of the switch-magnet 142 through contact 148 and the switch then moves on to its first position. Number recorder, Figs. 2 and 5. The magnets 21 are arranged in a semicircle and their armatures 51 are mounted on a set of rods 47 normally held up by the arms 52 of a spring spider. Each rod 47 is provided with a number of pins 54, one for each digit arranged in a helical row so that only one at a time is 'n position to operate one of the rocking levers 38, one of these levers being mounted adjacent to each rod 47 in each level. When one. of the magnets 22 is energized after the recording of a digit, the armature lever 97 releases the stop 60 and the disk 59 is rotated by the spring 66 till the stop 60 reaches the next armature lever 97, so turning the pinion 56 and by means of the spur-wheel 55 all the pinions 48, which, being feathered to the rods 47, turn them to. bring the next set of pins 54 into the operative position. The disk 59, Fig. 5, has an insulated contact-ring 61 with a gap 62 on which a brush 73 carried by a contact ring 71 on the disk 68 normally rests; when the disk 59 rotates, a circuit is closed from battery 144, Fig. 1, through interrupter 143, magnet 24, brush 72, ring 71, brush 73, ring 61 and brush 63 to earth, and an intermittent current flows until the magnet 24, Fig. 2, by means of the pawl 77, ratchet-wheel 75, and pinions 74, 69, has rotated the disk 68 to re-wind the spring 66. The preferred means for counting the record suitable for controlling automatic exchange selector switches, consists of an arm 89 carrying contact springs 91, 92 and is stepped round by means of magnets 25, 26 controlling the stepping and holding pawls respectively of a ratchet-wheel 87. When the arm passes one of the levers 38 that has been moved, the spring 92 is pressed against the lower spring 91 at the end of its path, the arm separates the springs 186, 187, Fig. 1, de-energizing magnets 25, 26, releasing the arm 89 which is returned by a spring and resets the displaced lever in passing. A separate counting set is provided for each row of levers 38. The impulse-transmitter 121, Fig. 1, comprises contact plates 122, 123, brushes 124-126 and a commutator 128, of conducting-material with insulating-segments, which can be moved to twelve positions relative to the plates 122, 123 besides the normal position. In operation, the commutator is adjusted to the required position laterally, and is then moved vertically, the insulating segments passing under the contact brushes 124-126 and then breaking either the line circuit or the short circuit of the resistance 127.