said by NOCMan:The device makes a connection to an arbiter device on the network's edge where they have a softswitch deal with the voice and data traffic. In the end, not only does it eat your bandwidth, but it also has to traverse back to your carrier and be processed and retransmitted anyways.
The primary function of any femtocell device is to increase your signal quality because many homes are hostile to wireless signals from cell towers, most newer homes with energy efficient attic barriers and windows can actually block or make your signal worse. The addition of a femtocell would fix your indoor problems.
This applies to all carriers, AT&T's decision to make you pay, and use your minutes is probably not smart, since you're likely to use half the resources you should get some sort of benefit such as 3:1 ratio of minutes used when you're on a femtocell.
They should do this, because for a few ten millions of dollars in hardware and contracts, they're essentially masking cellular congestion without paying out the billions it actually costs to build out new networks. Towers are not cheap in an era where cities demand hundreds of thousands of dollars in concessions from the cellular provider and in many cases weaken the improvements with height restrictions where the cell phone company now pays a lot of money and the tower does not benefit the residents of the area as much as if they were allowed to keep the requested height.
I challenge anyone who has crappy signals in a urban area and look at your city council requests of the cellular providers. You'll see that what the provider requests and the city's demands can actually work against you getting better cellular service.
VOIP is CHEAP really CHEAP!