Works is to install asterisk pbx on my server, install vTiger connector , configure it to make and receive call through vTiger, with existing voip provider and zoiper software.
vtiger is already existing, inbound call has to be redirect to one operatot
7 freelancers are bidding on average €125 for this job
I will do this in very less time. I have professional experience in VoIP industry and currently working with two international telecom companies. I will do your work in less amount about 80 .