Free voicemail greetings
Flashing Busy Signal (Fake Error)
This is a genuine flashing busy signal from the 1970's, when they were nearly extinct. Unlike a regular busy signal, a flashing busy essentially picks up and hangs up the line with each tone, creating a thunking noise that modern phone systems no longer make. In addition, because it was dialed as a long distance call, you can hear an extra burst of 2600Hz tone with each flash. This was part of the trunk signaling protocol used in those days. (Sampled from Evan Doorbells library at phonetrips.com)