Thanks for this input.
Just to make sure, the requirements are the same for PTP820s as are for PTP650? -As stated in in THIS post.
"The PTP 650 can be powered from 802.3at Type 2 (also known as PoE+ or PoE Plus) supplies, providing that:
(a) The power source provides power on the {1,2}{3,6} pairs. This is called "Alternative-A". PTP 650 are not compatible with "Alternative-B".
(b) The power source applies power without waiting for negotiation with the ODU sometimes referred to as passive or legacy mode
(c) The power source has sufficient capacity for the power used by the ODU.
(d) The length of the power cable is not more than 100 m."
Kind regards