Noise When Someone Hangs Up the Phone
Puzzle 1 of Handmade Gifts Easy Pack
Question is: Noise When Someone Hangs Up the Phone
and the answer is: DIALTONE
Word Meaning:
DIAL TONE — A telephony signal, usually in the form of a sound, used to indicate that the telephone exchange is working, has recognized an off-hook, and is ready to accept a call.
Definitions from Wiktionary.