Free VoIP Or Paid VoIP
Source: VoIP Providers List
There are certain features that the paid VoIP provider might provide which a free one might not. One such feature is the 911 emergency call service functionality. This particular issue has to do with the difficulty of pinpointing a geographical location of a call that is being routed through the Internet. FCC has regulated in 2005 that all VoIP providers hooking up to PSTN network are required to comply with providing full 911 call compatibility or otherwise not to obtain new customers in areas where it is mandatory.