Subscriber-Loop Digital Transmission Using Opto-Electronic Transmitters and Receivers

The efficiencies of different methods for subscriber-loop digital transmission are compared, using as a criterion the cost per bit/second per kilometer of wire, denoted "CSP". Approaches to reduction of CSP are suggested, in particular the use of opto-electronic transmitters and receivers in a differential connection, resulting in a relatively noise-immune subscriber line. A graphic method for the analysis of opto-electronic digital transmission lines is described.