so the dial up modem allows you to access the Internet by converting digital data into analog signals that can travel through the telephone lines , and on the receiving end that modem will convert thous analog signals into digital data which your computer can understand so my question is does cable modem work the same way ?

2 Answers 2


The basic principle of converting digital 1s and 0s into frequencies is identical, but almost all of the details are different.

  • The frequencies which encode the digital signal are different
  • The signalling rates are different
  • The electrical interface to the telephone network is different to that of the cable network
  • The interface to the computer: in the dial-up modem there is normally an RS-232 interface to connect to the computer; in the cable modem it's usually ethernet
  • The dial-up modem is only connected some of the time; the cable modem is always connected
  • The dial-up modem was basically a serial communicating device, not necessarily anything to do with the internet or any kind of packet-based communication
  • The cable modem is pretty much only for internet and packet-based communication
  • The methods of authentication are completely different, as the dial-up systems normally authenticated before any packet-mode was initiated

"Modem" is a portmanteau word for MOdulator/DEModulator. In a nutshell, digital data is modulated into an analog signal by the transmitter, transmitted over a line, and demodulated back into digital data on the receiver side.

There are numerous ways to do this, depending on what kind of transmission line you have.


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