RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
NextPlane - NextPlane offers cloud-based, scalable unified communications federation service for the enterprise.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Voxer - Turn your phone into a Walkie Talkie. Don't waste time on phone calls and voicemails.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs
Sameroom - Chat interoperability-as-a-service