How come my wireless internet connection keeps disconnecting

Is this a 2.4GHz cordless phone?

Yes it is

Well that's always going to be a problem. Your wireless router and phone share the 2.4GHz freq. Every time you use the phone, the phone grabs the freq. all for itself and completely blocks the wireless router until you hang up. You could try other channels and maybe find one that doesn't interfere. If not, you need to use a different phone, one based on a different freq., perhaps DECT (1.9MHz), 5.8MHz, etc.

http://en.wikipedia.org/wiki/Cordless_telephone#Frequen...