Need do develop a full IPRN billing [login to view URL] experience preferred but if you have worked on VOIP billing systems it will work.
Already have a working system needs changing on as [login to view URL] to start on an immediate basis
3 freelancers are bidding on average $2333 for this job
I have recently did this work for one of our clients using VOIP feel free to message me to see demo of our work. We might save your time because we already have source code