Signaling modules

FreeTDM supports a wide range of analog and TDM protocols. Even for the same protocol (for example, PRI) there are several modules that implement it, each with different strengths and weaknesses. The following is a list of the most commonly used modules.

ISDN signaling modules

ISDN is a protocol still widely used over T1/E1, and BRI telephone lines. FreeTDM supports several ISDN stacks, most of them open source. This is the list of the modules you may come across and a brief description of their use case.

Sangoma ISDN Module (ftmod_sangoma_isdn)

This module offers telco-grade signaling support for both PRI and BRI signaling; however, it is only usable if you have Sangoma cards with the native Sangoma IO module (ftmod_wanpipe). The module is open source, but relies on a closed source binary library that can be downloaded for free from the Sangoma website (more details about this later in this chapter). This stack is fully supported by Sangoma.

LibPRI Modules (ftmod_libpri)

This...