Hi Chathura,
In this setup, IP phone should detect two supplies and stop the one because it is IP phone, which is getting power from two power sources, not H510.
As per my understanding, possible damage could be to IP phone, as it is getting power from two power sources.
I do not think that IP phone could pass the power using its POE port because its a PD (powered device), not PSE (Power Sourcing Equipment).
Syamantak Omer
Syamantak Omer
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