Network Interface Box
In order to connect my Relay Box and Thermometer to the local network and the Internet, I built a special interface box using an RCM2200 microcontroller. I am not using anywhere near all of the available I/O lines, so this box is expandable by connecting another board to a DB25 connector.
A similar task could have been accomplished using a parallel, serial, or USB port on a standard PC.
I chose to use ethernet because network connectivity is almost universally available in modern operating
systems and programming environments. I have systems running Windows, Linux, and FreeBSD and I typically
write programs in C, Java, Perl, or LabVIEW. Ethernet makes it easy to interconnect everything, locally
Top view, with the cover removed
Bottom view, before the board was mounted in the case