Ive got a Netgear GS108PEv3 switch.
How can i enable / disable the POE function on a port by port basis on this switch, i couldnt find anything in the manual or by hunting around the web GUI.
You cannot disable the POE ports in this switch.
The ports are auto-sensing,
(802.1af) they will enable PoE once the switch has discovered a signature resistance on the designated pair.
POE+ or 802.1at devices which, your switch uses. These leverage a.c impedance using a capacitor on the phantom transformer circuit to detect a POE compliant device. It then uses LLDP-MED to negotiate power levels of the device.
None of the POE versions will supply a legacy device (non POE compliant) power if it doesn't detect the signature circuitry signal of a POE standard.
If your model supports the console, you could try there. But it looks like it was left out by design.
Hope this helps.