Is the `twisted-pair` line transfer `digital data` and `ADSL` line transfer the `modulated electrical signal`?

Question

From the WiKi:

Modem (modulator–demodulator) is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used with any means of transmitting analog signals, from light-emitting diodes to radio. A common type of modem is one that turns the digital data of a computer into modulated electrical signal for transmission over telephone lines and demodulated by another modem at the receiver side to recover the digital data.

From snapshot, is the twisted-pair line transfer digital data and ADSL line transfer the modulated electrical signal?

Answer 1

To answer your question, "yes".

In your image, the twisted pair connection is Ethernet, carrying digital information in the form of a square wave.

To be able to transmit this on a telephone circuit (ADSL) which is designed for analog transmission, the square wave needs to be modulated into an analog signal that is compatible with the phone line. The analog signals are above the human hearing range, but usually a DSL splitter is installed to pass the low frequencies to telephone equipment and to prevent interference with the higher frequencies, such as reflections and ringing (not phone ringing, but more like signals bouncing back and forth).

You can read more about modulation at Wikipedia.

Answer 2

ADSL is a set of standards for modulating digital data onto voice-grade twisted-pair cabling.

Ethernet (what you just call "twisted pair") modulates digital data onto data-grade twisted-pair cabling (category 5 or better). Ethernet also defines framing and addressing to connect a local network together.

Both use copper cabling and electrical signaling but they are quite different.