I have a customer who wants to install a wireless LAN at home but he is conscious about the bad health effect of having an always on wireless router or access point because he has children and a pregnant wife in the house. Is it possible to setup a wireless router or access point that when the wireless is not in used, ie data is being transmitted, the device is in "listen only mode" where it does not transmit anything. However, when a client is turned on and looks for a signal, this would "wake up" the wireless router/access point and it then begins to transmit. The client can find the wireless router/access point by the MAC address. I told the customer that this is impossible at this point because 802.11 spec says that in infrastructure mode, the wireless router/accesss point always transmits a beacon so that the clients can know what signal is there. Sure, one can disable the SSID broadcast, but the actual allegedly bad radio waves are still being tranmitted regardless whether it is being used to carry data or not. Is this true? How about ad-hoc mode? Come to think of it, this is like wake-on-LAN in the wired world where the PC will wake up from deep hibernation when an incomming "magic packet" arrives via the NIC from some computer in the LAN or from the Internet.