Since both our facilities were installed with the same model of voice IP phone system (Samsung OfficeServ) a year ago we've continuted having the voice breaking-up issue while calling between the two facilities using four-digit extension. Both facilities have a connection of 3 T1s and reserve dynamic cQoS 1,536K for public voice and another 768K for site-to-site phone.
I want to know if the breaking-up issue on VOIP is "normal"? And we should live with it? What could be the cause and how to fixt it?