I'll just put this out there for those of you attempting to use this module:
I alluded to an issue in the original post, where on some softphone clients it would duplicate the message 120+ times. It will then usually crash/freeze the freeswitch process. It turns out, this was not a problem with the softphone client. It is a problem with Freeswitch. And apparently, not even with the SMS module itself.
This bug report indicates that it is an issue with the underlying handler. In spite of the lack of any apparent definite resolution to that bug report, we have only replicated the problem under 1.6.x versions of Freeswitch and not 1.8.x, so it looks like the problem has been fixed. I believe
@MTR has also experienced similar results.
Unfortunately, our production systems are currently running 1.6.x, so we have had to disable the module while prepping a transition. There are some complicating factors that make this transition difficult, which I won't go into.
Suffice it to say that I strongly recommend that if you are considering using this module, make sure that you on Freeswitch 1.8.