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US 4,231,017 AGranted
Switching matrix equipment having a series circuit of relay coil and self-holding diode at each crosspoint
AssigneeHitachi, Ltd.
InventorsToshikatsu Kiriyama, Yoshiro Hasegawa
Life of this patent
Estimating the term…
Abstract
A switching matrix equipment is disclosed for use in a telecommunication switching system. Each crosspoint comprises a series circuit of a relay coil and a self-holding diode. First and second switch groups cooperate to select a crosspoint and to fire a self-holding diode of the cross point. After the self-holding diode is fired, the crosspoint related is held or sustained by means of a third switch group with a lower voltage than the threshold voltage of the self-holding diode.
Claims6
A switching matrix equipment comprising:
- (a) a relay matrix having series circuits each including at least one relay coil connecting at one end to one end of a self-holding diode with a threshold level and each disposed at each crosspoint;
- (b) a first means with first and second switch groups for designating a row and a column of said relay matrix, in which a crosspoint of said relay matrix is selected by closing a single switch of each of said first and second switch groups and a voltage exceeding the threshold voltage level of the self-holding diode at the selected crosspoint is applied to the diode thereby to fire the same diode;
- (c) a second means with a third switch group for holding the crosspoint selected of said relay matrix, in which the self-holding diode at the crosspoint selected by said first means is fired and then the crosspoint selected is held at a voltage below the threshold voltage level which is applied through a switch of said third switch group correspondingly related to the crosspoint selected.
Dependencies are inferred from the claim text.