SIP IP PABX Phone system with 4 to 96 FXS/FXO ports SIP ... Attendant, 3-way-conference; Embedded SoHo IP PBX phone system with 4,8 or 16 FXO analog ports, and 8 ... it allow extensions to be boundled with cell phone, and it also directly integrates with VoIP service provider networks. Depending on ... 60 remote extensions, and 8 to 16 analog trunks. With its flash memory capacity, RT20 also supports built-in ...