According to the request of corporation, industry and operator's voice service, CNG8000 is a trunk media gateway with high performance price ratio and good protocol compatibility. CNG8000 implements the transformation between ISDN PRI signaling and H. 323, SIP signaling, while transforming the media stream between PSTN carrying channel and IP network. CNG8000 supports the digital trunk E1/T1 interface adopting ISDN PRI signaling at telephone network, and accomplishes the controlling and maintenance of the users' call. It can be easily maintained and rapidly put into the use of corporation and operator's construction of (NGN). Voice interface: 1-16E1 VOIP Channels: 30-480 Trunk interface: BNC, RJ48 ( 75/120banlancing resistance ) Ethernet interface(RJ45): Two pieces of 10/ 100M Base-T Serial interface(RJ45): One piece of RS232(CONSOLE administration port) PSTN Protocol: ISDN PRI, support ITU PRI China No. 1. CAS, QSIG, DSS1 IP Protocol: Sip 2. 0 H323/V4(RAS, Q931, H235, H450)RTP/RTCP Codec: G. 723.1(5.3k 6.4kb/s); G.729A/B(8kb/s); G.711A /U(64Kb/s) Voice quality: TOS; Jiffer Buffer; VAD, CNG Network Protocol: HTTP, BOOTP, FTP, TFTP, IP, NAT, ICMP, ARP, DHCP, PPPoE, SWMP, Diff-serv Echo cancellation: G. 168(64-128ms) Fax: FRF, T38, T30, confidential fax