Hi! I can advice u Elastix! Very good worked open source project! I builded about 10 call structures on this soft with cisco phone/softphone. I can do it on VM or dedicated or local server. System have CDR,IVR, power monitoring, audio records, voice mail and many impotent for the call-jobs things! For 10 users my setup price 100$,for 100 users 500$, for 1000users 1000$. 10$/h support. U welcome!!!