Softphones offer the flexibility of making a call without the need for a dedicated device. If you’re a Skype user you’re probably used to the benefits of free and cheap international calls. Unlike their proprietary counterparts, open source softphones can be deployed on as many devices as required throughout the enterprise, without additional licence fees.
1. QuteCom
QuteCom is cross-platform (Windows, Linux, Mac OS X) and integrates voice and video calls and instant messaging. The number of protocols supported is on the same level as other multi-protocol IM clients. The application is developed with the Qt cross-platform toolkit.
URL: http://www.qutecom.org/
Licence: GPL
2. SIP Communicator
SIP Communicator is a cross-platform VoIP and instant messaging client developed in Java. Like other multi-protocol IM clients, SIP Communicator supports the popular protocols like Jabber, AIM, ICQ, MSN and Yahoo! Messenger. As the name indicates, voice communication is done with SIP and file transfers between clients is now supported for the XMPP, MSN, Yahoo! Messenger, ICQ and AIM protocols.
URL: http://sip-communicator.org
Licence: LGPL
3. SFLphone
SFLphone is a SIP and IAX2 (Asterisk) compatible softphone for Linux developed by Canadian Linux consulting company Savoir-Faire Linux. Its main features include support of unlimited number of calls, multi-accounts, call transfer and hold. Call recording is another useful feature.
SFLphone has clients for GNOME (integrated options), KDE and Python and it now supports the PulseAudio sound server, so users can experience additional functionality like sound mixing and per-application volume control. The softphone is designed to connect to the Asterisk open source PABX.
URL: http://www.sflphone.org/
Licence: GPL3
4. Empathy
Empathy is a unified communications client that supports text, voice, and video chat and file transfers over a variety of protocols. Empathy uses Telepathy for protocol support and is the default chat client for the GNOME desktop. Fedora Linux has also adopted Empathy as its default UC client. Being multi-protocol Empathy supports popular messaging services like XMPP (Jabber/Google Talk), MSN, IRC, Salut, AIM, Facebook, Yahoo!, Groupwise and ICQ. Voice and video call support is also multi-protocol and can us SIP, XMPP, Google Talk and MSN. Empathy’s other features include sharing and viewing of location information, group chat, and support for collaborative applications.
URL: http://live.gnome.org/Empathy
Licence: GPL
5. Ekiga
Ekiga is an open source VoIP and video conferencing application for the GNOME desktop, but it can be used with KDE as well. Ekiga uses both H.323 and SIP for voice and has a number of enterprise features like integration with Novell Evolution and LDAP support. Administrators can block some settings if required. To improve the user experience, Ekiga supports jitter buffering, echo cancellation and wideband codecs. Simultaneous account registration is supported as is multiple network interfaces Ekiga.net also offers free SIP accounts for VoIP.
URL: http://www.ekiga.org/
Licence: GPL
