In addition to the technology-independent SM classes described, the SM standard T1.417 also contains technology-specific guidelines. In the first issue of T1.417, there is one specific underlying technology, namely, pulse amplitude modulation; however, there are three distinct families of technology specific guidelines. The technology specific guidelines include 2B1Q-based SDSL, PAM per G.991.2 Annex A, and PAM per HDSL4 using 776/784 kb/s asymmetric PSDS.
|Frequency Band (kHz)||PSD (dBm/Hz)|
|0 < f < 4||−101, with max power in the in 0–4 kHz bands of + 15 dBm|
|4 < f < 25.875||−96 + 21.5 × log2(f/4)|
|25.875 < f < 138||−38|
|138 < f < 307||−38 −48 × log2(f/138) ...|