Gostaria de saber se é talvez impossível?
- O Anexo A é ADSL sobre POTS
- O Anexo B é ADSL sobre ISDN
- O Anexo J é ADSL2
pode ser possível se você puder encontrar um firmware revisado para o seu modem.
DSL: Anexo A versus B
It's a different DSL protocol defining how the internet circuit is combined with the phone circuit on a telephone line. Modems for Annex A can't be used on Annex B lines and vice versa. Annex B was designed to work in collaboration with ISDN telephone lines (and can be used on normal POTS lines) which is why it became the standard in Germany. UK has/had very little ISDN services, so they adopted Annex A.
Traditionally the protocol was hard-coded into the modem firmware, so could not be changed, but more modern modems can sometimes be re-flashed or re-programmed, (sometimes with hacks) with different firmware so can be changed. Manufacturers don't encourage or support changing the protocol because of support issues.
Fonte DSL: Anexo A versus B