MirX LAN Communication

I have a pair of 4ch wired network MirX relay boards.

They are on a closed LAN. I can only seem to get them to work if I have a DHCP server on the network, How do I get them to communicate with each other via a simple unmanaged network switch?

Hi,

These products are not recommended for unmanaged networks. We highly recommend you have a DHCP enabled router managing the network.