TDMoIP is mainly used to transmit voice signal over IP network. It has 1-4 E1 interface, 2 local Ethernet port and 1 uplink Ethernet port. TDMoIP-4 can connect TDM device and user’s Ethernet seamlessly and reliably on the standard low cost wireless or lineate Ethernet/IP configuration, without affecting the voice quantity. Being transparent to the TDM signal, this model assures connecting to physical E1 interface of any device seamlessly, such as PBX, mobile base station, SS7 signaling device and voice mail system. It can be used in the communication system based on E1, such as LAN, WAN, MAN and wireless network.