It uses the internet for phone calls. If you have DSL then you need your phone line any way so why pay for another phone service. If you have cable modem then you could use it instead of your regular phone service but if your cable internet goes out or your power goes out and your PC
goes down or your cable modem or router goes down then your up the crick as they say with no paddle. The local 911 is an issue with most any VOIP service as when you dial 911 you need to hit your local 911 center but with most VOIP if you dial 911 you end up with the local 911 center for what ever location the VOIP hub is. After all at some point the VOIP calls must get converted back to standard phone signals so 99.5% of the worlds users can receve the call.