Ring (software)

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Ring VOIP logo.svg
Original author(s) Savoir-faire Linux Inc.
Stable release
1.0 / 21 July 2017; 13 months ago (2017-07-21)
Preview release
Beta 2[1] / 3 November 2016; 22 months ago (2016-11-03)
Written in C / C++
Operating system Linux, FreeBSD, Microsoft Windows, OS X, Android
Platform x86, x86-64, 32- and 64-bit ARM, powerpc, sparc,
Available in English, French, German, Spanish, Russian, Chinese, Italian, Vietnamese
Type VoIP, telephony, softphone, SIP
License GNU General Public License 3
Website ring.cx

GNU Ring (formerly SFLphone) is a SIP-compatible softphone and SIP-based instant messenger for Linux, Microsoft Windows, OS X and Android. Developed and maintained by the Canadian company Savoir-faire Linux,[2][3] and with the help of a global community of users and contributors, Ring positions itself as a potential free Skype replacement.[4]

Ring is free and open-source software released under the GNU General Public License. In November 2016, it became part of the GNU Project.[1]

Two account types are currently available, and many of each type can be configured concurrently. Both types offer similar features including messaging, video and audio. The account types are SIP and Ring. A SIP account enables the Ring softphone to connect to a standard SIP server and a Ring account can register (or use an account set up) on the decentralised Ring network which requires no central server.

By adopting distributed hash table technology (as used, for instance, within the BitTorrent network), Ring creates its own network over which it can distribute directory functions, authentication and encryption across all systems connected to it.[5]

Packages are available for all major Linux distributions including Debian, Fedora, and Ubuntu.[6] Separate GNOME and KDE versions are available.[7] Documentation is available on Ring's Tuleap wiki.[8]


SFLphone was one of the few softphones under Linux to support PulseAudio out of the box. The Ubuntu documentation recommended it for enterprise use because of features like conferencing and attended call transfer.[9] In 2009, CIO magazine listed SFLphone among the top five open-source VoIP softphones to watch.[10]

One step beyond SFLphone, Ring retained SIP compatibility and support, while adding a new communication platform that does not require a centralized server to establish communication.


Ring is based on a MVC model, with a daemon (the model) a client (the view) communicating. The daemon handles all the processing including communication layer (SIP/IAX), audio capture and playback, and so on. The client is a graphical user interface. D-Bus can act as the controller enabling communication between the client and the daemon.


  • SIP-compatible with OpenDHT support[7][11]
  • Unlimited number of calls
  • Instant messaging
  • Searchable call history
  • Call recording[7]
  • Attended call transfer
  • Automatic call answering
  • Call holding
  • Audio and video calls with multi-party audio[7] and experimentally video conferencing[12]
  • Multi-channel audio support (experimental)
  • Streaming of video and audio files during a call
  • TLS and SRTP support
  • Multiple[7] audio codecs supported: G711u, G711a, GSM, Speex (8, 16, 32 kHz), Opus, G.722 (silence detection supported with Speex)
  • Multiple SIP accounts support, with per-account STUN support and SIP presence subscription
  • DTMF support
  • Automatic Gain Control
  • Account assistant wizard
  • Global keyboard shortcuts
  • Flac and Vorbis ringtone support[12]
  • Desktop notification: voicemail number, incoming call, information messages
  • SIP Re-invite
  • Address book integration in GNOME and KDE
  • PulseAudio support
  • Jack Audio Connection Kit support
  • Locale settings: French, English, Russian, German, Chinese, Spanish, Italian, Vietnamese
  • Automatic opening of incoming URL
  • End-to-end encryption used for chat, video and voice[13]
  • Decentralised

See also[edit]


  1. ^ a b GNU Ring beta 2 release announcement
  2. ^ Free Software Foundation
  3. ^ Ring's Tuleap Server
  4. ^ Robertson, Donald. "The Licensing and Compliance Lab interviews Guillaume Roguez, Ring Project Director". Free Software Foundation. Retrieved 2016-02-19. 
  5. ^ Say Hello to Ring (Savoir-faire Linux)
  6. ^ Ring Download
  7. ^ a b c d e Sanders, James. "Privacy-focused Skype alternative Ring shows promise - TechRepublic". TechRepublic. Retrieved 2016-02-19. 
  8. ^ Ring's Tuleap wiki
  9. ^ Official Ubuntu documentation
  10. ^ "5 open source VoIP softphones to watch". CIO. Retrieved 2016-02-19. 
  11. ^ OpenDHT project on Github
  12. ^ a b Huber, Mathias. "Software-Telefon SFLphone KDE 1.3.0 veröffentlicht » Linux-Magazin". Linux-Magazin. Retrieved 2016-02-19. 
  13. ^ "Protocol". Once an encrypted and authenticated peer-to-peer communication channel is available, the SIP protocol must be used to place a call and send messages. 

External links[edit]