Noun
English Wikipedia has an article on:busy signalWikipedia
busy signal (plural busy signals)
(US, telephony) An audible signal to the calling party that indicates failure to complete the requested connection; an engaged tone
I got an answering machine for my phone.... Now, when I'm not home and somebody calls me up ... they hear a recording of a busy signal. Steven Wright
I'd either get a busy signal or a message saying to call back," said Jackson, of Mission Bend, who was furloughed from his contractor position with Wood Group Mustang Engineering in March. Source: Internet
That’s more or less the family, then there are the artists that we work with: Aidonia, Busy Signal, Masicka, RDX, Capleton, Beenie Man, Alozade, Elephant Man, and Chico. Source: Internet
For example, if a customer encountered a reorder tone (a fast busy signal), it could indicate "all circuits busy," or a problem in the destination exchange. Source: Internet
If the called party's line is in use, the exchange returns a busy signal to the calling party. Source: Internet
People talk about calling dozens, if not hundreds, of times and always getting a busy signal. Source: Internet