I designed a board hat that has 2 output relays, and an RJ45 jack.
The RJ45 brings:
5V supply to VIN
Ground to GND
Relay 1 common
Relay 1 Load
Relay 2 common
Relay 2 load
Because projects can get complex fast I added pin headers to select Relay 1 coil to be on Pin 2 or Pin 6 of the board and Relay 2 coil to be on Pin3 or Pin 7 of the board.
You can also select whether you want NO or NC contacts on the relay.
So you can break out Uart and a couple industrial control signals.