8x8 X Series - X Series connects teams across channels and around the globe, giving you access your most critical information securely, from any location.
XO Hosted PBX - Hosted PBX is a scalable UC solution that uses cloud technology to integrate HD voice & data services, mobility, along with advanced calling
Vonage Business Communications - Vonage Business Communications transforms communications and activates conversations anytime, anywhere. Learn more about unified communications now!
Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
Broadvoice - Cloud PBX solution for SMBs
Sipdroid - Free and open-source SIP/VoIP Client