Ansible - Radically simple configuration-management, application deployment, task-execution, and multi-node orchestration engine
Tragofone - White-label VoIP Softphone with WebRTC and Auto-provisioning
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
PhonerLite - PhonerLite enables your PC to use it for internet telephony (VoIP , Voice over IP, SIP).
Puppet Enterprise - Get started with Puppet Enterprise, or upgrade or expand.
tSIP - tomeko.net/software: SIP client for Windows.