Modulating Demodulators (modems) modulate outgoing digital signals from a computer or other digital device to analogue signals for a conventional copper twisted pair telephone line and demodulates the incoming analogue signal and converts it to a digital signal for the digital device.
By modern standards the term 'modem' is much broader, yet still used due to being highly recognisable. It is typically a separate hardware peripheral, but can be managed through software and or built-in to a device/computer as well. Modems are one of the ways that computers can connect to the Internet, via either Dialup (Narrowband) or Broadband services.
Related Articles:
> Router
> Dongle