How is dsl connectivity difference dial up?

Dial up uses audio frequency tones to deliver data. 0 to 4000 Hertz

DSL uses higher frequencies in to deliver more data. 25,000 - 1,000,000's Hertz.

A low pass filter separates Audio frequency from the digital information.

DSL contains many subsets includes ADSL1, ADSL2, ADSL2+, VDSL and VDSL2.

DSL speed is also dependant on distance from the phone exchange and quality of the copper lines + connections to the premises.

DSL speed is also much lower when the cables are under water.