Elie,
This is a generation 1 unit that is no longer produced or supported by quintum. Quintum does have software available on their web site, but it is only beta software, meaning it has not been fully tested and if there are any problems they will not fix it. Many have tried using this software and I think that success is about 50% or so. So you can give it a try or see about getting a generation 2 quintum unit that does support sip.
MikeM
mike_voip@hotmail.com