Table:
text: Asymmetric digital subscriber line
ADSL standards
ADSL standards
Version Standard_name Common_name Downstream_rate Upstream_rate
ADSL2+ ITU G.992.5 ADSL2+ 20.0 Mbit/s 1.1 Mbit/s
ADSL2+ ITU G.992.5 Annex M ADSL2+M 24.0 Mbit/s 3.3 Mbit/s
ADSL2++ (up to 3.75MHz) ADSL4 52.0 Mbit/s ? 5.0 Mbit/s ?

Question: What is the 20.0 Mbps downstream rate version under asymmetric digital subscriber lines?