GSM Dongle based Software Development

Hi All Bidders, We need Experienced developer to develop GSM Based Software For Call Conference with multiple Dongles. This Software should have following functionalities. 1)Call Conference (Vise versa , Two way like phone calling.) 2)call history 3)mute un mute for separate & all Devices 4)call waiting 5)conference Auto Receive and join conference 6)Optional : hold number can be disconnected automatically) 7)white list 8)black list 9)contact list Experienced Bidder preferred.