... interface of PSTN and IP network; Detailed:VoIP Media Trunk Gateway contains a total of four models, ... -102 is a new generation of small-capacity media gateway,with a powerful processor, embedded operating system ... 2 ) and SIP protocol transform. as well as media transfers between the PSTN and IP network. it can ... net work for branches Figure 3 Media gateway of IPCC Figure 4 Conference Bridge Solution