telecommunications hardware and operating software based on xDSL (high-speed Digital Subscriber Line) technology, namely, digital signal processors, software for data encoding/decoding and error detection/correction using adaptive signal processing; xDSL systems comprised of line units, remote units, doublers, central office shelves, remote enclosures, and network management software for use with telephone company central site operations in order to provide point-to-point, one site connecting to another site, and point-to-multipoint, one site connecting to multiple sites; xDSL systems comprised of hardware access platforms, line units, interface cards, desktop units, namely, computers and workstations, and network management software for use within campus/LAN (local area network) environments; electronic bridging units for coupling Ethernet networks, power supplies, and centralized SNMP (simple network management protocol) network software; integrated circuits containing single-chip xDSL circuits