Signalschaltvorrichtung

1,230,672. Reed-relay switching matrices. NIPPON ELECTRIC CO. Ltd. 10 July, 1969 [10 July, 1968], No. 34878/69. Heading H4K. A reed-relay cross-point switching matrix has a bias field applied to the reeds of each crosspoint, the reeds being associated with remanent magnetic cores carrying operate and release windings, the operate windings being connected in series with a rectifier between corresponding row and column control wires, the release windings of a row or column being connected in series for energization coincident with co-ordinate operation of a cross-point in the row or column. As shown in Fig. 4 the remanent magnetic cores 402 have operate windings 403, and series connected release windings 404 and 405 in each row and column respectively. Each release winding produces an mmf one third that of the operate winding and each cross-point has its reeds biased by a permanent magnet. Coordinate operation of a cross-point is by means of a flux in the operate winding that aids bias and, should it be necessary to clear the other cross-points in the associated row and/or column, switch 409, and/or switch 407, is closed so that the select potentials drive the corresponding series-connected release windings in parallel with the operate winding and so as to oppose bias. In a modification, Fig. 6, not shown, the release windings may be driven in series with the operate windings, the release windings of each row or column being shorted out by a switch if the release function is not required. Fig. 7 shows such a disposition of the release windings for the columns only and with shorting switches omitted since, in this embodiment, bias is produced by an auxiliary magnetic core 701 at each cross-point and the saturating windings 702 on these cores are driven in series with the release windings at each operation of a cross-point in a column. The bias saturating windings 702 may be in series with the associated operate winding and rectifier at each crosspoint, Fig. 8, not shown.