How to extend cable to Anchor to more than 100 m without additional power supply?

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PoE Passthrough (sometimes depicted as PoE In/PoE Out) is an approach where small PoE extender unit can provide PoE input and several PoE Outputs without required external power adapter. This enables to prolong cable distance from network switch to anchor to several hundred meters.

One should always consider voltage drop among the cable once the anchors are daisy chained. Anchor consume maximally 2.5W. Here is a cable length calculator.
The second thing that need to be considered is what type of the PoE is used – Passive PoE or Active PoE?

There are different PoE Passthrough extenders for Passive PoE and (Active) PoE IEEE 802.3af/at.