Thanks, yes I could see that this was handled with events. Could you please give more details (that does not seem obvious to me while looking at sofia_presence.c) When and why is the event triggered ? What information do I get with the event ? Then I have a design question, is it mandatory to (as this is done in mod_sofia but I guess for a lot of reasons) process the event in a separate thread ? Thanks for the information (and sorry if my questions are not relevant, I don't know the event system at all). François On Thu, 18 Feb 2010 00:13:08 -0500, Michael Jerris wrote: This all uses the event system. Take a look at how we handle the events in mod_sofia, it should be pretty easy to do the same in mod_openzap. Mike On Feb 16, 2010, at 4:33 AM, François Legal wrote: I was wondering whether or not a facility was available to send message waiting indicator (from mpd_voicemail) using openzap. I know this feature is not available in openzap (I'm in the process of coding it for analog channels) but as message indication can be sent via mod_sofia, I wonder if a frame is available in FS core.