1,RoIP Gateway,GSM VoIP,sip gateway 2,Buildin GSM/CDMA Module 3 ... Mode 4,Link up radio RoIP Gateway,GSM VoIP,SIP Gateway Description:What is a Cross-Network Gateway? ... It enables voice communications among the Radio, VoIP, GSM, and Public Announce (PA) networks.It ... Protocol (RoIP) which converts radio voice communications into VoIP.It links up various radio networks together in ...