A data transmission system forming a network including transmission line sections comprising traditional infrastructure such as AC power line (mains), twisted-pair (e.g. CAT-5) and coaxial cable wiring interconnected with a novel adapter to form a data system also providing data transfer over an extended length and diversity of connected equipment. Further combined with a data bridge connected to conventional format data (e.g. Ethernet) and to the traditional data infrastructure wiring, the novel adapter permits connection to any 2 of twisted pair/multi-pair, coaxial and power mains for data flow therebetween.