Digital closed network constructed from a telephone exchange and a key telephone system and signal transmission method of the digital closed network.

摘要

A digital closed network is constructed from a telephone exchange (10) and a plurality of telephones (20), wherein each telephone (20) is further for connection to a network device (30), such as a computer, hub, network printer etc. Over the closed network, data and video information are transmitted in the form of packets. Moreover, communicating voice signals are converted to the form of voice packets by the telephones (20), whereby the superior transmission quality is obtained. Furthermore, the transmission priority among the voice, data and video packets is controllable in the closed network, thus when there is a great quantity of packets being transmitted, the voice packets still possess high real time transmissions.