You can backpower SwitchBlox via one of its PoE ports, however there are a few caveats here.

1. SwitchBlox uses passive PoE, which just applies a 44-57V on the ethernet lines without first doing any autonegotiation. This passive PoE is unlike PoEBlox which uses active PoE which is incompatible with passive PoE

2. The current version of SwitchBlox ships with components DNP'd that disables PoE by default. If you remember we were getting issues with the shared ground on SwitchBlox causing issues in systems where other devices did not have full transformer isolation. This means to enable PoE, you'd need to resolder these components. They are:

• U8, U9 and U10: ZXMS6004DN8Q
• SW2: DSHP05TSGET
• R43: 0603 0R resistor

The schematic of the PoE circuitry is below.

3. When backpowering SwitchBlox with PoE via one of its ports, you must:

• Not use any of the other ports to output PoE
• Not use the 5V rail on SwitchBlox
• Not plug in another supply to the main Vin port
• Not use the Vin port to supply other devices

The reason for these restrictions is the limited current capability through the U8/U9/U10 MOSFETs.