At least as described by you.
The fix for him was a router firmware update and moving from the crowded channel 11 to channel 1. He's on DSL and we had to double check those line filters.
Have a dell wireless router (Truemobile 1184) and everytime I buy a cordless phone with addl handsets it knocks the internet out . It works fine with our old 2.4gz cordless but the phone is not keeping a battery. First we tried a new 2.4 and it knocked out internet everytime the phone rang. Then tried several 5.8 and it does the same thing. Finally figured out to change channels on the router and getting inconsistant results( new laptop sometimes works old are fine). All the forums I read say to change to 5.8 which are wirless friendly, but this is not working for us.