Description of technology

IP-telephony is a technology based on real-time voice and facsimile transmissions by means of digital packets in networks using the IP protocol (LANs, Internet).

IP-telephony is used in networks with circuit switching (voice transmission) and in networks with packet switching (data transmission). Voice recognition and transmission from one network to another uses special devices called gateways. Each gateway is linked to phone lines at one end and the IP-network at the other. This lets the gateway connect one phone to any other, as well as to any computer connected to the Internet.

Analog voice signals are transferred via the telephone network to the gateway linking the IP-network and the telephone network. The gateway digitizes and compresses the voice signal. It is split into IP-packets and transferred via Internet to the destination. Packets arriving at the gateway nearest the other subscriber are converted back to analog (voice signal) and fed to the phone line. Packets may travel simultaneously in both directions from one subscriber to the other.

Connection to MTU-Inform's IP-telephony network is implemented in the following way: Internet access uses the Ethernet 10/100 Base-T interface, and phone numbers use the standard FXS interface. Phone numbers are allocated at the company's switching node. Phone traffic transfer uses VoIP technology in the TCP/IP network, through the gateway between the telephone and TCP/IP networks. The Cisco 5350 multi-service access hub used as a gateway is connected to the company's switching node by E1 digital data streams (2 Mbps).