dialling tone

US and Canadian dial tone

noun

a continuous sound, either purring or high-pitched, heard over a telephone indicating that a number can be dialledCompare ringing tone, engaged tone

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012