dial up
phrasal verb with dial verb [ I or T ] uk/daɪəl/ usUK -ll- | US -l-
[ I or T ] COMMUNICATIONS
to call a telephone number:
I dialled up the answering service and found two messages.
Someone had found his office number on an internet phone directory and dialed him up.
[ I or T ] INTERNET, COMMUNICATIONS
to connect to a network or to the internet using a dial-up modem:
The broadband connection is always on, so there's no need to dial up any more.