Dork. is right. If the phone ONLY affects the wireless network it has to be a wireless phone in the house, and it's because the phone is on the same frequency band as the wireless network. Your friend can change the channel he has his network set to, but most cordless phones use a variety of frequencies too, so that may not do the job. I'd recommend that they either deal with phone wires, or buy a phone on a different band, such as 5.2GHz.