RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Phonebooth - Phonebooth is one of the leading voip providers, providing phone systems & phone service for small businesses.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs
Eir SIP Voice - eir SIP Voice is revolutionizing the core communications tool of business that carries both calls and data over just one connection.