T-Mobile began testing a new service late Wednesday that it says will cure many of the issues that plague cellphones. Dubbed Hotspot @ Home, the technology takes advantage of the increasing prevalence of broadband Internet access and home WiFi routers to potentially eliminate the need for more than a cellphone, according to T-Mobile. In the current Seattle-only trial, subscribers must own phones with built-in WiFi but can connect to either a wireless router at home or a T-Mobile public hotspot to switch from cellular networks to VoIP. The plan gives users unlimited calling time from these points and improves the often poor reception found in some indoor areas. These two advantages effectively allow a cellphone to replace a land line in some cases, T-Mobile says. HotSpot @ Home is currently available in the trial area for $20 per month in addition to a minimum $40 per month with a two-year contract; the two phones currently on offer sell for $50 each with these terms. T-Mobile hasn't provided details of a formal rollout beyond Seattle, but it isn't expected to be widely available until 2007.