SIP-compatible with OpenDHT support[16][20] Unlimited number of calls Instant messaging Searchable call history Call recording[16] Attended call transfer Automatic call answering Call holding Audio and video calls with multi-party audio[16] and video conferencing[21][22] Multi-channel audio support (experimental[citation needed])[clarification needed] Streaming of video and audio files during a call TLS and SRTP support Multiple[16] 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[21] 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[23] Decentralised (no internet connection necessary)