http://projects.ag-projects.com/projects/documentation/wiki/Repositories
https://wiki.asterisk.org/wiki/display/AST/Secure+Calling+Tutorial
http://sylkserver.com/download/
https://forum.mikrotik.com/viewtopic.php?t=137634
provisioning
https://github.com/lynt-smitka/Cisco-SPA-CZ-provisioning
webrtc phone
https://wiki.freepbx.org/display/FPG/WebRTC+Phone-UCP
to be continue …