Sip-Tools - Automated calls and answering machine

sipcall - Automated calls over SIP/VOIP with TTS
sipserv - Answering machine for SIP/VOIP with TTS

What is very important is that when building kernel for RaspberryPi, you can't just use any version of it. Only special version that is ported to RaspberryPi will work. Unfortunately, current upstream version (found on kernel.org site) is not compatible with RaspberryPi. Also, versatil_config is not good for RaspberryPi, you should use bcmrpi_defconfig instead (found on RaspberryPi compatible kernel sources) or bcmrpi_emergency_defconfig if your plan on using buildin initramfs.

ARCH=arm CROSS_COMPILE= make modules_install INSTALL_MOD_PATH=