When you're looking at land lines, I think the potential exposure to radio frequency fields is not an issue. As I said previously, the things people talk about when we look at wireless are hand-held mobile phones, where the device is held close to the body. As I commented earlier, base station transmitters' field strengths or ambient levels where populations reside are far lower than anything you would experience from a hand-held device.
There are other potential sources of exposure starting to become more common, such as wireless computer networks. We may be in the presence of wireless communications right now, if there's a local area wireless network. But again, the field strengths there would be more akin to those you might experience from a base station transmitter, and much lower than you would experience from a hand-held device.
So all the focus, from a health point of view, has really been on the mobile phones themselves.