The first is the Aviosys ethernet controller in a box. The DB15HD connector to the far left connects to the relay board. The D-series connector in the middle does nothing.
The image below is what switches the 230VAC devices (lighting in this case). The transformer on the left has a primary of 230VAC and a secondary of 24VAC. One side of the 24VAC secondary is commoned along all the coil (K1) side of these Omron LY2 relays. Caution, these are 24VAC relays.
This is the Aviosys relay control board, As you can see, the other side of the 24VAC secondary from the 24VAC transformer is commoned up to a NO (normally open) contact (in this case, the common contact). These boards have two NO (normally open) contacts, and two NC (normally closed) contacts. I had to remove the relays, cut a couple of tracks, and solder a couple of wires to the NO side to make it work at the screw terminals.
The four wires you see heading up actually connect to the other side of the 24VAC coil (K2) on the relays. Pretty simple stuff.
As a result, when the board is sent a specific URL, the output address is triggered which will pull in the smaller relay, which will pull in the higher current rated relays, and in turn switch on and off the device connected at the contact.
Hope this is of some use to you, and some other Geekzoners out there who are looking to control a basic device or two.