Its true that the specs are not symmetric in ADSL. The CO (Central Office) end is different from the CPE (Customer Premises Equipment) end, and two CPE devices cannot talk to each other. Among other things, the engineering work had to take into account that at the CO end a bunch of wires would come together and leak RF between each other.
G.SHDSL is more common in a 1:1 configuration (although I think the ends may still be not symmetric) because it was designed as a T1 replacement.
However some devices that could do a single line of CO were made, that can therefore talk to a CPE.
G.SHDSL is more common in a 1:1 configuration (although I think the ends may still be not symmetric) because it was designed as a T1 replacement.
However some devices that could do a single line of CO were made, that can therefore talk to a CPE.
See also https://www.revk.uk/2017/12/its-official-adsl-works-over-wet...