A common problem that many people run into involves the setup of their home wireless networks. Some people that use wireless internet routers/modems in conjunction with cordless phones have ongoing issues with voice quality during their phone calls (static and clicking), as well as intermittent data connections to their wireless routers. Not a good situation for anyone.
What gives? The answer is pretty simple.
The vast majority of the people with this issue are using 2.4 GHz cordless phones. The 2.4 GHz is the frequency that the telephone handset uses to communicate with the telephone base. The problem is that most wireless modems and routers operate on the same frequency, which can cause serious interference issues with both voice and data.
Your best bet?
Upgrade your phone. Choose one of the cordless phones currently available. As of this writing, 5.8 GHz and 6.0 GHz are the current offerings. As a rule of thumb, just stick with the highest number available to avoid any conflicts. You'll find that your new phone will sound clearer, and you'll be able to get online without any problems.
It pays to do a little inventory around the rest of your house, as well, checking for other devices that run on a wireless frequency, such as some types of alarms, baby monitors, etc. It's possible that any of these can cause interference with your cordless phone, wireless router, or both. A process of elimination should tell if any of these are causing issues. Other items, such as microwaves, may not interfere with your wireless routers, but be aware that they can cause interference on your cordless phone when they are in operation.