I put a 1747-DPS1 in line with a Pro-face AGP4105-G1-D24 HMI and a MicroLogix 1000. It has allowed me to be online with the MicroLogix without unplugging the HMI. It is working great. I tried to put one in between a 1747-NET-ENI and a MicroLogix 1500. The 1747-NET-ENI is hooked to an Hirschmann Spider 5TX swith which in turn is connected to a PanelView 700+, an SLC 5/05, PowerFlex 70, and a PC via ethernet. strange results. The PanelView still worked great and I was able to get online with my laptop using the DPS1. The 5/05 and the PowerFlex 70 did not communicate with the 1500 however. My local AB "expert" is at a loss and is contacting AB. Will let you know what I find out.