From Longman Dictionary of Contemporary Englishdial toneˈdial tone noun [countable] TCT American English the sound you hear when you pick up the telephone that lets you know that you can make a call SYN dialling tone British English
Examples from the Corpus
dial tone• When he called at noon, her answering machine emitted a long series of beeps followed by a dial tone.• When he tried to call again, he could no longer get a dial tone.• You should have heard a dial tone, a ringing sound, then burbling tones.• Previous years were ok once you got the sought after dial tone.• He lifted it carefully and got no dial tone then saw the plungers were taped down.• You should be able to feel the dial tone burr. 2.• There was a click, but she stood listening to the dial tone, steadied by its urgent drone. 