Applies to: Documentary standards-based PoE selection and read-only status interpretation. Numerical site solver remains IEEE802.3af/at only; Type3/4 education is outside its calculation coverage.
- Signal path
- Ethernet source → injector LAN IN (data) → Documented injector supply → injector (power) → POWER+DATA OUT → compatible powered device
What the path requires
- Identify PSE, PD and any injector/splitter revision. Stop for unknown passive injection, damaged/overheated cable or an unverified DC-supply substitution.
Worked documentary examples
Worked documentary path
Documented outcome: Source-defined example: a newly attached PD does not start and the Catalyst log reports ILPOWER POWER DENY while other ports remain powered. The first supported interpretation is remaining-budget denial; a different cable category alone does not add source budget.
Alternative or unknown branch
Documented outcome: If the source only says PoE without standard/type or the injector has no trustworthy identity, stop selection and obtain the manual. Do not assume a passive injector performs IEEE detection.
Follow the observation
Read the result before moving to the next branch. Leave unavailable evidence unknown.
1. The PD needs a different type or the socket is data-only.
Check: Read PD requirements and the exact port/injector standard and supported port range.
What it supports: Connector fit is not a compliant power path.
Next action: Choose a documented PSE/PD combination; do not force power or substitute an arbitrary DC adapter.
Stop / escalation: Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
2. LAN IN and POWER+DATA OUT are reversed or a splitter is confused with the injector.
Check: For TL-POE150S V3, compare physical port labels with the V3 manual.
What it supports: The intended data/power roles have not been established.
Next action: Have the responsible person restore the manufacturer-documented topology with the specified supply and compatible PD; do not transfer another revision's LED rules.
Stop / escalation: Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
3. ILPOWER POWER DENY or insufficient remaining budget is reported.
Check: On authorized Catalyst9000 administration, read show power inline and the relevant logs.
What it supports: Cisco defines the denial as insufficient remaining source budget.
Next action: Ask the administrator to assess planned allocations, supplies and source budget. Do not remove unrelated devices or increase power limits as a generic fix.
Stop / escalation: Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
4. Those values differ.
Check: Compare allocated/reserved power, power available to the PD and measured port consumption fields.
What it supports: PSE output/allocation, PD allowance and actual draw are distinct quantities.
Next action: Retain field names/units and PD demand. Do not subtract an arbitrary cable loss or equate a switch's nameplate with power available at the PD.
Stop / escalation: Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
5. The PD still fails or reports overdraw/fault.
Check: If per-port type and budget are adequate, compare a supported short intact channel and inspect status.
What it supports: Cable/path, PD and PSE detection/current behavior still need model-specific investigation.
Next action: Collect exact PD/PSE model, version, symptoms and logs for vendor support; no live probing, power forcing or firmware/reset shortcut.
Stop / escalation: Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
Your next useful observation
Collect exact PD/PSE model, version, symptoms and logs for vendor support; no live probing, power forcing or firmware/reset shortcut.
Keep these limits
- Stop for heat, smell, damaged insulation, unknown power source or power faults. No energized pin probing, supply substitutions, static-power forcing, shutdown/reload or firmware procedures.
- Documentary sources; no PoE electrical measurement or device test.
Source documents, revisions and inspection methods
Troubleshoot Power over Ethernet on Catalyst 9000 Switches
Cisco · Document 215636, updated 2024-09-05
General Troubleshooting; No PoE on one/group of ports; ILPOWER POWER DENY; Inline Power & Budget
Inspected 2026-10-23 by public_page. AI primary-source text inspection; not independent human review or hardware measurement
Platform-scoped read-only observations; intrusive recovery, firmware, power forcing and live electrical work excluded.
Read the original sourceTL-POE150S PoE Injector User Guide V3
TP-Link · Rev3.0.0,7106503937,2012
printed pp.2–5: port labels, connection roles and specifications
Inspected 2026-10-23 by public_pdf_text. AI primary-source text inspection; no hardware test
Exact historical V3 documentary injector direction, IEEE802.3af and 10/100/1000 interfaces. Other hardware revisions require their own guide.
Read the original sourceSource-documented education. Hardware behavior and independent human review have not been performed for these examples.