The GNU Gatekeeper is a free H.323 gatekeeper based on the OpenH323 project. You can use it to manage a Voice-over-IP network and let endpoints (e.g., Netmeeting) communicate through symbolic names. It also has an external interface for billing and other applications. It runs on a number of Unix versions (including Linux and Solaris) and Windows.
The REMWAVE Carrier Core platform is a stable platform to set up a voice over IP carrier (ITSP). It contains a complete billing, rating, and routing engine and is used by some of the largest ITSPs. The Carrier Core is free for deployment and contains a billing engine (based on Oracle express 10g edition, though larger editions are available), a SIP proxy and registrar, a customer care system, and templates to set up a customer self service portal.
Noojee Receptionist for Asterisk provides a software-based interface for receptionists. It provides the ability to dispatch calls using a database of all staff and external parties or by phone or extension number. When looking up internal extensions, the status of each extension is displayed, saving the receptionist time as they no longer have to dial the number to determine if the party is available. When an extension is busy, the call can be placed into a "hold and transfer" mode that will automatically transfer the caller when the extension becomes available. It can also periodically inform the caller that the party is busy and gives the option to continue waiting, leave a voice message, or be put back through to the receptionist.
The CommuniGate Pro Community Edition provides a single address and identity for all forms of Internet communications. You can check your e-mail, chat with colleagues via Instant Messaging and VoIP, view multiple calendars (and other presence features), maintain address books, and view streaming RSS news feeds, all through the powerful Flash-based interface.
Linphone is an audio and video Internet phone with GTK+ and console interfaces. It uses the SIP protocol, and is compatible with most SIP clients and gateways. It can use various audio and video codecs such as Speex, GSM, G711, G722, ilbc, amr, Theora, H263-1998, MPEG4, H264, VP8, and snow.
Bayonne is the telephony server of the GNU project. It offers a script-driven threaded multi-line state event telephony service on GNU/Linux, xBSD, and Microsoft Windows for building voice response systems, and uses telephony plugins for runtime driver configuration. It also features "TGI" for making Perl applications "telephony aware". It may be used to build telephony-based system administration, home automation, automated attendant, v-commerce, and voice messaging systems.
OTRS is a platform independent Web-based help desk system that supports service organization of any kind (e.g. IT service, customer and technical product service, complaint management, public services, etc.) to increase their efficiency. It increases transparency as well as service quality and lowers your total cost of ownership. It has been certified ITIL V3 compatible by PinkVERIFY for incident, problem, change, service asset and configuration, request fulfillment, and knowledge management. Other ITIL processes like service catalog and service level management are supported as well.
Baudline is a time-frequency browser designed for scientific visualization of the spectral domain. Signal analysis is performed by Fourier, correlation, and raster transforms that create colorful spectrograms with vibrant detail. Conduct test and measurement experiments with the built in function generator, or play back audio files with a multitude of effects and filters. The baudline signal analyzer combines fast digital signal processing, versatile high speed displays, and continuous capture tools for hunting down and studying elusive signal characteristics.
Speex is a patent-free compression format designed especially for speech. It is specialized for voice communications at low bit-rates in the 2-45 kbps range. Possible applications include Voice over IP (VoIP), Internet audio streaming, audio books, and archiving of speech data (e.g. voice mail).