[Freeswitch-users] FreeTDM + libsng_isdn in Windows - can't get it to work (causes FS crasch)

Peter Olsson peter.olsson at visionutveckling.se
Fri Feb 11 09:28:30 MSK 2011

I'm trying to get FreeTDM and libsng_isdn working in a Windows environment, but with no success. This is what I've been trying to do;

First of all - I'm using lastest git HEAD (as of right now), latest Sangoma driver (, latest libsng_isdn (7.1.0), I build everything in Visual Studio 2008.

At first I got lots of side-by-side errors (VC runtime errors) when loading mod_freetdm. I found that the reason for this was ftmod_sangoma_isdn.dll was compiled with _DEBUG, even in release mode (which is what I'm using), I changed this to NDEBUG instead, and that got rid of the error (I guess this should be updated in the project file though).

After this I got this error (even though the libsng_isdn was installed on the computer), the reason for this seems to be it can't find libsng_isdn.dll;
2011-02-11 07:02:32.591375 [ERR] ftdm_io.c:4989 Error loading C:\freeswitch\mod\ftmod_sangoma_isdn.dll [dll open error [126l]

Then I simply copied libsng_isdn.dll into the freeswitch folder, and after this FS crasches immediately when trying to load mod_freetdm.

So I guess by now it finds all files and dependencies, but instead it causes a crasch. Did I do something wrong, or is there something in the code that needs to be updated to get things working in Windows? This is just on a lab system, so I'm able to do whatever tests you want me to.


Peter Olsson

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