Because Google Voice provides such a competitive and feature-rich service that not only includes free VoIP and SIP calls across North America and internationally at fantastic rates, in addition to a huge range of services such as voicemail, conference calls and voice transcription, it was inevitable that since its inception it would attract the ire of other competitors who would block it, or sue in courts to have the government legislate against it.
Offers connections ranging from capability for a couple of simultaneous calls for small PBX-equipped businesses to an unlimited number of channels for larger businesses.