Local area network connecting computer products via long telephone lines

Claim 1

A local area computer network for connecting a plurality of computer products, the network comprising: a telephone cable containing four or more wires at least two of which are not used to transmit telephone signals, said telephone cable including at least two predetermined signal lines selected from the unused wires in the telephone cable that are unshielded and are used as a bus to transfer signals between computer products on the network while simultaneously allowing a telephone to use a remaining pair of wires in the telephone cable; and connector means associated with each computer product for connecting a computer product through the at least two predetermined signal lines to a second computer product that allows exchange of information between computer products in the network; wherein said connector means comprises: first interface means for receiving signals from and for passing signals to each of the two predetermined signal lines; voltage suppression means connected to the first interface means for limiting voltage surges and for suppressing any static voltage that appears at the first interface means; second interface means having at least two signal lines for being connected to a computer product for sending signals to, and for receiving signals from, said computer product according to the E.I.A. RS-422 standard; and isolation means connected to the first interface means and to the second interface means, for transferring signals between and for providing electrical isolation between the first and second interface mans, and for enhancing the sharpness of rise and of fall of the leading edge and the trailing edge of a signal passing between the telephone cable and said computer product in the network.