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Double Service Protection Circuit

IP.com Disclosure Number: IPCOM000097967D
Original Publication Date: 1961-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Waszak, ML: AUTHOR

Abstract

Asynchronous, possibly recurring, demand signals from X Demand 1 are processed by double service protection circuitry 2...6 so that each X signal (or each burst of recurrent signals) is serviced only once by Computer 7.

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Double Service Protection Circuit

Asynchronous, possibly recurring, demand signals from X Demand 1 are processed by double service protection circuitry 2...6 so that each X signal (or each burst of recurrent signals) is serviced only once by Computer 7.

The double service protection circuit is implemented in AND-INVERTER (- OR-INVERTER) logic. Circuit blocks 3 and 5 respond to all + inputs with a - output, or to one or more - inputs with a + output. Each trigger includes two blocks with cross-coupling. Trigger T4 is set by the X signal from Demand 1, and remains set until reset by a C pulse from Computer 7, gated to indicate completion of service for the X demand (C). With T4 set, each B pulse from the computer, via block 5, sets both Service trigger T6 and Protection trigger T2. T6 provides a service signal input to Computer 7 until reset by the succeeding A pulse. T6 is set again and again upon occurrences of the B pulse, so long as T4 remains set, i.e., so long as the demanded action is pending.

The circuit, thus, retains an indication of the demand, until such time as the computer performs the action demanded. Meanwhile, it is possible for Demand 1 to drop the demand signal and to make another demand for service, either as the result of a new set of circumstances or a burst-type recurrence of the original demand. This signal attempts, via block 3, to set T4 for the second demand. This second demand is inconsequential if the original demand is still pending.

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