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.
PBXMate software Sip Trunk for improving Audio Quality. Removes noise originated from external mobile phones or from the call center, keeps audio level at a comfortable level and removes echo.