The basic Barix boxes are one direction only. The new 1000 series pro stuff is bi-directional. For the record I have messed with intalling several Barix systems now and LOVE them. They are one of the best values in broadcasting today IMHO. I plan on buying some more for remote stations we are going to build around here and use a fiber-feed school internet system to get the audio to our stations. The cost and the reliablity of these darn things are almost hard to belive. At the low price they cost a guy can have two of them just in case!