Strong interface capacity,Optimized call route,SMS functions,Caller's ID,Many more other functions ... access to PSTN, CDMA, GSM, and IP networks.2. Optimized call route: can access to different networks CDMA, GSM, PSTN etc ... , best solution to call cost. With IP-PBX, users can make international calls while enjoying local call payment, and make free call for company’s internal ...