This standard describes the electrical and functional characteristics of Very-high-bit-rate Digital Subscriber Line (VDSL). VDSL is designed to operate on a single pair of unshielded metallic cable. It offers a variety of bit rates (22/3 Mbps@ 6/6 Mbps@ 10/10 Mbps@ etc.) on loops that are typically shorter than 4500 ft. VDSL can operate over loops of various gauges@ including loops with bridged taps. Specifically@ this standard: ? Describes the reference configuration; ? Specifies the PSD and total power constraints that apply to VDSL systems; ? Specifies the modulation method; ? Specifies the transmission convergence layer (TC); ? Specifies the OAM requirements; ? Specifies the link activation and de-activation method; and ? Describes test procedures and requirements. Multi-mode ADSL/VDSL implementations are beyond the scope of this standard. Purpose This document specifies a minimal set of functional requirements to assure interoperability of equipment from various manufacturers. Particular implementations may have additional functions and capabilities that are beyond the scope of this document. The document also specifies the allowed spectrum use of the system.