Recommendation ITU-T G.9700 specifies power spectral density (PSD) mask requirements for fast access to subscriber terminals (FAST), a set of tools to support reduction of the transmit PSD mask, profile control parameters that determine spectral content, including the allowable maximum aggregate transmit power into a specified termination impedance, and a methodology for transmit PSD verification. It complements the physical layer (PHY) specification in Recommendation ITU‑T G.9701.