Patent GB-1170808-A (GB)
Title: Improvements in or relating to information storage arrangements
Inventor: GIANOLA UMBERTO FERDINANDO
IPC: H04M1/276
Filed: 1967-05-31
Abstract: 1,170,808. Circuits employing bi-stable magnetic elements; substation equipment. WESTERN ELECTRIC CO. Inc. 31 May, 1967 [1 June, 1966], No. 25082/67. Headings H3B and H4K. [Also in Division G4] A repertory dialler stores a plurality of frequently called telephone numbers in coded reversed domain form along a magnetic domain wall wire, a stored number being located for non-destructive read out or re-writing by selectively establishing an index domain reversal either in the same wire or in a second wire in a position marking the number required, all the stored numbers and the index being then propagated along the wire or wires simultaneously until the number required is positioned for reading by arrival of the index domain at a reference position. Fig. 1 shows an arrangement using two domain wall wires DW1, DW2, up to 50 telephone numbers, each of up to 16 digits (but normally 7), being stored along wire DW1 with each digit represented by two spaced domain reversals at positions determined by a two-out-of-seven code. Wire DW2 has a permanent reversed domain reference position, and is coupled by coils C1-C50 any of which, when energized by the subscriber closing a number select button NS1-NS50 and until the reference domain at the position coupled with coil 37, establishes a reversed index domain in a position along the wire which identifies the location of the number required. Number sending. The subscriber opens switch S1 by going of-hook and closes the number select button NS1-NS50 corresponding to the number required. A number-read switch S4 is then closed. A monopulser 34 then triggers one sequence of four-phase advance pulses from a source PSF which are applied to coils P1,P2 (not shown), coupled with both wires. This advances the domains in both wires by one step. The fourth advance pulse sets a bi-stable flip-flop FFB which causes the information stored in both wires to progress backwards, stepwise, under the control of four-phase reverse pulses from a source PSB, backward movement being terminated when the reference domain in wire DW2 is located by coupling with coil 37. The reference domain is reestablished by a pulse from monopulser 40 in a coil 41A, this pulse at the same time passing through coils 41B and erasing any index domains which are present in wire DW2. A pulse from monopulser 12 sets up a reversed index domain at a position determined by the closed select button NS1-NS50, and commences forward stepwise movement of the domains in both wires DW1, DW2 by triggering forward advance pulse source PSF. When the index domain in wire DW2 is sensed by arrival at a coil 14 a stepping switch SW coupled to a seven gate converter 44 is reset. Each stored digit in wire DW1 of the number identified by the index domain is read out in turn by a coil 13, and is registered in the converter 44, the stepping switch advancing one step as each digit is read. When the seven digits of the number are registered, the stepping switch provides a signal which gates a parallel output from converter 44 to a utilization circuit U. The latter converts the input 2/7 code into a multifrequency code for transmission to the exchange. Forward domain movement is terminated when the index domain reaches coil 55. The stored information in both wires is stepped backwards until the reference domain arrives at coil 37 when the subscriber goes on hook. Writing a new number. The subscriber opens off-hook switch S1, closes write switch S2 and closes number read switch S4 in that order. The circuit responses are substantially the same as those for number sending up to the stage where the selected index domain is detected by coil 14. As bi-stable flip-flop PFFC was previously set during this operation an erase pulse is passed into an erase conductor 17 which eliminates the stored telephone number identified by the chosen index domain. The depression in sequence of chosen digit select buttons, not shown, stores corresponding domain pairs along the wire DW1 by selectively energizing coils L1-L4, H1-H3 through a two-out-ofseven pulse source 11. Each time a digit select button is depressed, dial switch S3 is closed and opened and sets bi-stable flip-flop FFF. Forward movement of stored information in the wires takes place until stepping switch SW reaches its seventh position and resets FFF. This operation is repeated each time a digit select button is operated. Backward movement of the stored information until the reference domain reaches coil 37 occurs when the subscriber goes on hook.