GNU Bayonne - Telephony Server of the GNU Project - GNU Bayonne, the telecommunications application server of the GNU project, offers free, scalable, media independent software environment for development and deployment of telephony solutions for use with current and next generation telephone networks.
LinuxTelephony - LinuxTelephony is a resource for those interested in Computer Telephony on Linux and Open-Source CT projects
Voxilla - The broad goal of voxilla.org is to host a complete set of telecommunications modules for use with the GNU/Linux operating system. To that end, voxilla.org tracks, archives, documents, and develops such software. At the time of this writing, voxilla primarily functions as an archive, but several developers use it for other resources. The minimum goals set for voxilla are to have a complete archive, and to be responsive to developers who need to host software. Much of the original development focus has shifted to the Gnucomm project.