Flyback/Forward Transformers for PoE Coilcraft Flyback or Forward Transformers for Power over Ethernet (PoE) are transformers that offer dual outputs, which are configurable as one single higher power output. These transformers operate with a 9V to 57V input range (POE21, 22, 24, 33, 35, and 38). The flyback or forward transformers also operate with 33V to 57V input voltage range (POE23, 30, 36, 53, 70, and 72). Coilcraft Flyback or Forward Transformers are suitable for PoE applications up to 72W.