Carrier-class VoIP Media Gateway with 2/4/8 E1 optional, powerful DSP to support all time slots concurrent calling, dual-power TG1800 series is a carrier-class VoIP media gateway. There are three different models with 2*E1/T1, 4*E1/T1, and 8*E1/T1. It supports SIP-T/SIP/H.323 protocol to connect with SIP-T/SIP/H.323 soft switch, and supports PRI/SS7 signaling protocol to connect with PSTN. Up to ...