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If a GS-3xxx switch with active PoE detects external voltage on a PoE port, PoE is deactivated globally. This issue can occur if another switch with active PoE is connected to the GS-3xxx switcswitch, which supplies voltage on the port to the GS-3xxx. To prevent this issue, PoE has to be deactivated on the additional switch for the port to the GS-3xxx switch.
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