Abstract: A data communications system which comprises at least one group of subscriber data interface elements, with each interface element having at least one data input port and a data output port, and each output port being electrically connectable to a subscriber line of the telephone network to transmit data thereon without interfering with any telephone service that may be present on these subscriber line. A network data interface element, for each group of subscriber data interface elements, being located within a short distance from the farthest subscriber data interface element. Each subscriber data interface element having a data input port and a data output port, and each input port being electrically connectable to a subscriber line of the telephone network and in communication with these subscriber data interface elements thereover.