POE voltage rise time
Posted: Thu Apr 01, 2021 4:09 pm
This may simply be a limitation of the Netonix product line but I thought I'd ask. We have a radio vendor whose radios prefer 802.3af, 802.3at, 802.3at+, or 802.3bt PoE but will work with passive injectors as well. However, we found they would not always power up when plugged into our Netonix switches. We would end up having to cycle the port a number of time and eventually, the radio would fire up - usually.
In discussion with the vendor and testing with Netonix switches on their bench, they found the voltage rise time in the Netonix was out of the IEEE 802.3 Section Two spec for voltage rise time and as a result, a transistor in the Ethernet chip would go into oscillation and prevent the radio from powering up.
A solution we have found is to put a passive to active Ethernet midspan adapter in line between the Netonix and the radio.
I don't think Netonix claims to follow the 802.3 specification for POE - at least as rise time is concerned. However, is this something that could be addressed in firmware or is it tied to the hardware?
In discussion with the vendor and testing with Netonix switches on their bench, they found the voltage rise time in the Netonix was out of the IEEE 802.3 Section Two spec for voltage rise time and as a result, a transistor in the Ethernet chip would go into oscillation and prevent the radio from powering up.
A solution we have found is to put a passive to active Ethernet midspan adapter in line between the Netonix and the radio.
I don't think Netonix claims to follow the 802.3 specification for POE - at least as rise time is concerned. However, is this something that could be addressed in firmware or is it tied to the hardware?