With the beta of WP7 Mango, socket connections are possible with the WP7 Framework.
So I gave it a try and build a quick and dirty WP7 app to test it.
I use the socketserver by danssaertd ([forum.velbus.eu/t/a-velbus-server-mode-tool/4654/1))
At the moment I use a couple of customized classes from the Velbus library (the default library doesn’t work with the WP7 framework) and I do a connect-send-disconnect on every keypress, so no statuses at the moment.
I’m still trying to wrap my head around the new Socket class in WP7 to use a constant connection and get feedback.
If anyone is interested in the code or some hints/tips give me a shout.