I have a project where I would like send some simple low rate data over an existing 12VAC power line. The devices connected to line will need to retrieve the data and respond accordingly. I have looked at the X-10 implementation but it appears they are using custom transformers to couple to the power lines. I do like the idea of the 120KHz busts to represent bits so I may adopt that. Does anyone know of a way to couple a 120KHz signal to an 12V 60Hz AC line and remain isolated? I don't mind using a transformer if it is an off the shelf part.