I've run Cat5e network cable throughout an office and have a patch panel where ADSL & phones come in.
The wall sockets are all RJ45 so I can run either phone or ethernet over them.
If someone accidentally were to plug their computer into the wrong outlet (one which has the phone signal on it), will it do any damage to the ethernet card in the computer? I think in NZ the lines are up around 45V.
What about if the phone is ringing?
I was thinking of putting a reducer into those ports anyway so it'd be clear that the phone goes on those. i.e. http://www.jaycar.com.au/productView.asp?ID=YT6055