Our network is really simple. All of the computers (7 of them) are connected to the network via Ethernet cards and a Linksys router. The CNC machines are connected to the computers via RS-232/Parallel connection. We only use it for Uploading/Downloading programs and printing inspection reports from the machine probe data but it works fine. We have from 1 to 7 CNC machines connected to each of the computers by using a series of A/B/C/D switch boxes to send the signal to the intended machine.