Yate is a next-generation telephony engine. While currently focused on Voice over Internet Protocol (VoIP) and PSTN, its power lies in its ability to be easily extended. It supports SIP, H.323, IAX, MGCP, Jingle, Jabber, E1, T1, analogic, robbed bit, ISDN PRI, BRI, and SS7. YateClient is an Instant Messenger and Voice application for Jabber/Jingle IM, SIP, H.323, and IAX VoIP protocols.
Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one or more clients can attach to and detach from a central core, much like the popular combination of screen and a text-based IRC client, but graphical. In addition to this unique feature, it aims to be a comfortable chatting program.
Beem is an XMPP (Jabber) client for Android. Beem is compatible with any standard XMPP server or service (including Ejabberd, Openfire, Facebook, or Gmail). It supports SASL, proxying (Socks4, Socks5, HTTP), DNS SRV, and chatting with a specific resource. Beem is available on the Android market and on the software's own Web site.