For G.992.3 (ADSL2), the maximum bandwidth is (256 × 4.3125 ÷ 1000) = 1.104 MHz
For G.993.2 (VDSL2, Profile 17a), the maximum bandwidth is (4096 × 4.3125 ÷ 1000) = 17.664 MHz
Classical telephony uses the range 300 Hz to 3.4 kHz (i.e. a bandwidth of 3.1 kHz) which is less than one xDSL subcarrier's width (4.3125 kHz).
The following image (from Wikipedia) shows a generalised view (which ignores some of the minor details), using G.993.2, Profile 12a as the VDSL2 example --