Browse Prior Art Database

Card Ready Indication Circuit

IP.com Disclosure Number: IPCOM000079494D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Roseman, DB: AUTHOR

Abstract

Both functional operations and presence of a circuit card is detected with a relatively simple, low-cost circuit which senses a multiplicity of functions with a single output, reflecting the go/no go status of those functions.

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Card Ready Indication Circuit

Both functional operations and presence of a circuit card is detected with a relatively simple, low-cost circuit which senses a multiplicity of functions with a single output, reflecting the go/no go status of those functions.

Card 10 is edge connected to terminals 11 and 12. Terminal 11 introduces power to card 10 such as from a minus 48 volts source. This power may be filtered through choke 13, if desired, and passes through fuse 14 before going to circuit load 15. Terminal 12 is coupled to a digital input point for a sensing system such as an IBM System/7. Manual switch 16 is normally open so that biasing is introduced to transistor 18 via resistors 19 and 17. Accordingly, sensing of a ground potential at terminal 12 indicates that the manual override switch 16 has not been actuated, card 10 is in place and connected, and elements 13 and 14 are applying appropriate power levels to load 15. Alarm contact point 20 can also be coupled back to the sensing device, so that failure of fuse 14 after initial operation as indicated by an initial grounding of terminal 12 can be interpreted as the loss of fuse 14.

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