(1) To phone someone. See
rotary dial.
(2) Using the switched telephone network to send data from a computer to a remote device. Using a modem, the computer's digital data are converted to analog signals in the same frequency range as human voice. At the other end, another modem converts the analog back to digital. For home users, dial-up was the first Internet access service available. It was followed by ISDN, DSL, cable and fiber. See
modem and
dial-up network.