Members Thanks for your replies. I'm sorry for the delay - I only found that there were responses today when I brought up the forum page. I had specified in my profile to be notified by email whenever there were responses, so I have been watching my email - that didn't work out. Here is my setup. I wrote a vb.net Visual Basic application that runs on a windows 10 PC. The app sends USB serial port commands to a relay controller board to open/close 8 switches which control 8 12vdc relays on a board in the basement. These relays switch between 2 different antenna feedlines and insert various segments of feedline into the antenna feedlines to change the electrical length of the feedline for the selected antenna - thus tuning that antenna for the most efficient operation. I have a web site that explains the system with pictures and text. I can supply the URL, but it is a subscription service to amateur radio operators and requires membership for access. Getting back to the remoting: when a relay controller port upstairs closes or opens, I want a corresponding on/off switch in the basement to close which, when closed supplies 12vdc to the appropriate relay - current for a relay closure is only a couple of hundred milliamps. Currently, the relay controller is in the basement near the relays and a USB cable goes thru a 1" diameter hole i the floor and connects to the controller board. The controller and relay boards in the basement are only abouit 8 feet away from the upstairs radio operating location. The reason for the remoting project is the the proximity of the relay controller to the antenna feed lines causes the controller circuits to sometimes hang up due to the RF energy (100 watts). Therefore, I want to bring the controller circuit board upstairs and wirelessly send the open/close commands wirelessly to the relay boards in the basement. I'll close for now and let those who have responded digest this information.