Describes the physical medium characteristics for: - twisted pair multipoint interconnections in either 2-wire or 4-wire network topology in order to provide for half duplex or duplex data transmission capability, respectively; - a binary and bi-directional signal transfer of the interconnected endpoint systems; - the electrical and mechanical design of the endpoint system branch cables and the common trunk cable, which may be up to 500 m in length; - the component measurements of the integrated circuit type generators and receivers within the endpoint systems; - the applicable data signalling rate up to 1 Mbit/s.