DIALTONE

6 recorded uses

Date	Clue
2019-10-12	Sound around a cradle
2016-06-08	Feature of a landline, but not a cellphone
2013-07-03	Landline sound
2008-09-23	Sound after a hang-up
2005-05-08	Indication of service availability
2001-09-14	It may follow a click