A DSL modem (digital subscriber line modem) is
used to provide high data rates over standard telephone twisted
pair cables. A DSL modem supports one or
more of the DSL standards:
ADSL (asymmetric digital subscriber line)
SDSL (symmetric
digital subscriber line))
HDSL (high-speed DSL)
VDSL (very high speed DSL)
A DSL
modem may be an asymmetric modem or a
symmetric modem, depending on the type of DSL.
The transmission speed
depends on the length, quality and wire gauge of the
copper pair.