FIND BY PROBLEM · TROUBLESHOOTING
Link Drops, Interference, or Test Failures?
Organize the symptoms, conditions, link partner, cabling, power, and test records. Our FAEs return a reviewed troubleshooting checklist and tell you when deeper analysis is needed.
WHEN TO USE
Situations You May Be Facing
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Unstable Link or Intermittent Drops
Negotiation failures, frequent reconnects, or speed downgrades during bring-up or in the field, correlated with cable length, link partner, or temperature.
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Bit Errors or Low Throughput
The link comes up but drops packets, shows high CRC errors, or misses throughput targets under heavy traffic, pointing to signal integrity or magnetics parameters.
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EMC / Interference Issues
Radiated or conducted emissions exceed limits, immunity tests fail, or nearby power and RF modules interfere, and the coupling path needs to be located.
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Production or Certification Test Failures
Return loss, insertion loss, hipot, or PoE tests fail, and you need to tell a component issue from a layout or test setup issue.
TROUBLESHOOTING PROCESS
Initial Troubleshooting in Three Steps
First FAE reply within 1 business day. The more complete your information, the more targeted the checklist. We do not promise a test pass; we tell you clearly when deeper analysis is required.
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You · About 10 minutes
Describe the Symptoms
Tell us what happens, under which conditions, what is connected, which cable, and how it is powered. Attach any test records.
- Symptoms & conditions
- Link partner & cable
- Power & PoE
- Existing test records
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VOOHU FAE · First reply in 1 business day
FAE Review & Checklist
We assess each dimension below and list what can be ruled out, likely causes, and how to verify them. For items that cannot be judged remotely, we explain what is needed.
- Schematic / layout check
- Component parameters
- Troubleshooting checklist
- Items to verify
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You · Verify & report
Verify and Report Back
Work through the checklist and share the data. When needed we arrange sample comparison, lab testing, or on-site support until the cause is found.
- Step-by-step checks
- Report data
- Sample comparison
- Deeper analysis
TROUBLESHOOTING DIMENSIONS
Where We Look
Each direction gets one of three results:Ruled out / Likely cause (with verification method) / Deeper analysis needed (on-site or lab)
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Trigger Conditions
Correlation with temperature, cable length, link partner, power state, or specific traffic, and whether it reproduces reliably.
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Cable & Link Partner
Cable category and length, shielding and grounding, and the link partner PHY or switch model and negotiation settings.
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Power & PoE
PSE / PD role, power class, center tap current, supply noise, and ground loops.
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Component Parameters
Actual transformer and RJ45 part numbers, lots, and datasheet versions compared with the PHY recommendations.
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Layout & Grounding
Differential routing, reference planes, isolation gap, Bob Smith termination, and chassis grounding.
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Test Conditions
Test standard, fixtures, frequencies, and environment, to separate component, layout, and test method issues.
RELATED PRODUCTS & RESOURCES
Before You Submit
Related Product Lines
- LAN TransformersCheck parameters and lotsView →
- RJ45 ConnectorsCheck jack, shielding, and groundingView →
- Protective ComponentsTVS / ESD / GDT surge protectionView →
These are related categories. If the conclusion involves changing parts, we provide candidate parts and differences separately.
Downloads
Download Center →Published Technical Articles
- Ethernet Communication Troubleshooting GuideTechnical ArticleRead →
- Ethernet Conformance Testing GuideTechnical ArticleRead →
Articles show common symptoms and troubleshooting approaches and may not apply to your application.
Share Symptoms to Get a Checklist
Click to open the inquiry form and describe your requirements in detail. An engineer replies within 1 business day.
Weekdays 8:30–18:00 (UTC+8) · +86 400-1048-018
