PreViking is a telephony daemon written in C. It has been designed with a modular structure that easily allows the addition of different services and the support of different hardware. Current services include a calling card service and a call- back service. PreViking provides an API which includes many functions to do different telephony operations such as call switching, playing/recording messages, and listening/playing DTMF.
VOCP is a complete messaging solution for voice modems, with voicemail, fax, email pager, DTMF command shell and Text-to-Speech support, 4 graphical interfaces, and a Web interface. Callers navigate the system using a touch-tone phone and may send and receive faxes, voice mail, and pager messages, listen to text/HTML email messages, or execute configured programs on the host and hear the resulting output.
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.
PyGCID is a graphical CallerID application written in Python with the GTK toolkit. It uses an external program to fetch numbers from your CID hardware. It maintains a small database with the incoming calls, and has the ability to store a comment and a note on each call. It can also dial the numbers using an external program, and run a specific program for each number (for example, you can play different sounds for different numbers).
sms-queue handles an SMS queue for small networks or single user machines. It is designed for areas where many SMS messages are sent. It does not actually send the SMS itself, but instead calls an external application (depending on the SMS gateway you want to use) via a simple standard interface. The communication between client and server is based on a simple ASCII protocol over TCP/IP which should make it easy to develop your own frontend.