For Raspberry Pi GPIO header, for connecting sorts of RPi HATs
10/100M auto-negotiation Ethernet port, with PoE enabled
4x USB ports, allows connecting more USB devices
2x CSI camera interfaces
Onboard HDMI / DSI interfaces for connecting displays
Onboard USB TO UART, for serial debugging
Cooling fan interface, auto run on power up OR controlled by IO pins
Adopts isolated SMPS (Switching Mode Power Supply)