Access circuit for a time-shared data processing equipment

Claim 1

A selecting circuit comprising: a. a plurality of input terminals for application of respective request signals to the circuit; b. a plurality of storage circuits, each having a first condition and a second coNdition; c. a plurality of gating means interconnecting respective ones of said input terminals to respective ones of said storage circuits, for feeding request signals applied to said input terminals to the respective storage circuits to thereby cause those storage circuits to be triggered into their second conditions; d. means responsive to said second condition of any of said storage circuits to disable all said gating means and thereby prevent any further request signal applied to a said input terminal from being fed to its respective storage circuit; e. timing means connected to all said storage circuits, for initiating a predetermined time period upon setting of any of said storage circuits into a said second condition; f. means responsive to the cessation of a said request signal at a said input terminal, for normally resetting the respective storage circuit to its said first condition after said predetermined time period; g. fault detection means connected to said timing means and to said input terminals, for providing a fault signal on the condition that when said predetermined period elapses a said request signal still persists at an input terminal associated with a storage circuit in said second condition; h. means responsive to said fault signal to reset to its first condition the storage circuit then in it second condition; and i. means for applying said fault signal to the gating means of said associated storage circuit to inhibit that gating means, thereby preventing repeated triggering of that storage circuit if said request signal persists.