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Isolating Interconnection Failures Between Field Replaceable Units

IP.com Disclosure Number: IPCOM000083981D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Craft, DJ: AUTHOR

Abstract

The figure shows a driver circuit on a field-replaceable unit (FRU) 1 connected over a transmission line 2 to a receiving circuit 3 on FRU 2. Typically the FRU's are attached to the line 2 via relatively unreliable mechanical connectors such as those shown at 4 and 5. In such cases, it is more probable that errors in operation will be due to failures in connections to the FRU itself rather than failures within the FRU. Checking circuit 6 on receiving FRU 2 provides a means for detecting and isolating interconnection failures occurring at connections 4 and 5, for both analog and digital signals.

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Isolating Interconnection Failures Between Field Replaceable Units

The figure shows a driver circuit on a field-replaceable unit (FRU) 1 connected over a transmission line 2 to a receiving circuit 3 on FRU 2. Typically the FRU's are attached to the line 2 via relatively unreliable mechanical connectors such as those shown at 4 and 5. In such cases, it is more probable that errors in operation will be due to failures in connections to the FRU itself rather than failures within the FRU. Checking circuit 6 on receiving FRU 2 provides a means for detecting and isolating interconnection failures occurring at connections 4 and 5, for both analog and digital signals.

The incoming net on FRU 2 is connected via terminating resistor 7 to a voltage V(term), which is outside the normal operating voltage range V(low) to V(high) of the driver circuit 1. Compare circuit 8 forming part of checking circuit 6 has its inputs connected between the incoming net and a threshold voltage V(thresh), and is arranged to set an error latch 9 if the voltage of the incoming net goes beyond the threshold voltage.

Should either interconnection 4 or 5 between the two FRU's go even momentarily open circuit, the terminating resistor 7 will take the voltage on the input of compare circuit 8 beyond threshold V(thresh) and set error latch 9. Clearly, the receiving circuit 2 must be able to stand the terminating voltage V(term) on its input without damage and it is desirable that the receiving circuit...