Linphone
Linphone is a free voice over IP softphone, SIP client and service. It may be used for audio and video direct calls and calls through any VoIP softswitch or IP-PBX. Linphone also provides the possibility to exchange instant messages. It has a simple multilanguage interface based on Qt for GUI and can also be run as a console-mode application on Linux.
Both SIP service and software could be used together, but also independently: it is possible to connect Linphone service with any SIP client, and to use Linphone software with any SIP service.
The softphone is currently developed by Belledonne Communications in France. Linphone was initially developed for Linux but now supports many additional platforms including Microsoft Windows, macOS, and mobile phones running Windows Phone, iOS or Android. It supports ZRTP for end-to-end encrypted voice and video communication.
Linphone is licensed under the GNU GPL-3.0-or-later and supports IPv6. Linphone can also be used behind network address translator, meaning it can run behind home routers. It is compatible with telephony by using an Internet telephony service provider.
Features
Linphone hosts a free SIP service on its website.The Linphone client provides access to following functionalities:
- Multi-account work
- Registration on any SIP-service and line status management
- Contact list with status of other users
- Conference call initiation
- Combination of message history and call details
- DTMF signals sending
- File sharing
- Additional plugins
Open standards support
Protocols
- SIP according to RFC 3261
- SIP SIMPLE
- NAT traversal by TURN and ICE
- RTP/RTCP
- Media-security: SRTP and ZRTP