Freeswitch Freeswitch is a server for real time communication. Freeswitch can use several protocols for communication. It is written in C. Configuration The configuration is written in XML and files can be included. It has a root config file, which include all configuration files. The configuration files are include by a preprocessor. This is a example configuration for Freeswitch. The root config file includes the file vars.xml and the XML-files in the folder dialplan.