IP Telephony applications.
FreeSWITCH http://www.freeswitch.org
Asterisk http://www.asterisk.org
Callweaver http://www.callweaver.org
SER http://iptel.org/ser/
OpenSIPS http://www.opensips.org
SipX http://www.sipfoundry.org
ReSIProcate http://www.resiprocate.org
Gnugk http://www.gnugk.org
OpenSBC http://www.opensipstack.org
Asterisk Gui interfaces.
FreePBX http://freepbx.org
Vicidial (Astguiclient) http://astguiclient.sourceforge.net
VoiceOne http://www.voiceone.it
Billing Systems.
Asterisk2billing (a2billing) http://www.asterisk2billing.org
ASTPP http://www.astpp.org
AstBill (AstBilling) http://astbill.com
Freeside http://www.sisd.com/freeside
CDRTool http://www.ag-projects.com/CDRTool.html
Ispbs http://ispbs.hostplus.net/
Trabas http://www.trabas.com/opensource/
CitrusDB http://www.citrusdb.org/
