(or, well, one of their delivery services.)
🔊 Just a fair warning - there are some perhaps annoying glitch sounds in the attached recording. The volumes are normalized to limit loud spikes, as they were a lot worse in person. 😅
See also, the sequel: I broke Google TTS.
so, my phone service has a rather clever anti-spam tactic, which works like this:
- I receive a phone call from an unknown number, and it goes through screening when I answer it. It rings until the fifth ring, the voicemail greeting plays out, then I've got 30 seconds to judge if it's a spam robocall or if it's genuine
- If it's okay, I press 1, and it interrupts the ring/voicemail sequence and I answer the call like usual.
- If it's spam, I press ### (the # key by itself normally opens my PBX menu, so it doesn't go through) and hang up immediately.
Pressing ### and hanging up, will shove the call to voicemail, then launch a "DTMF bomb", which is a rapid sequence of over a hundred tones of DTMF keysmash, even including some of the "ABCD" keys. This has blown up spammers' cheapass PBXes, especially ones with poor security and too much trust given to the DTMF decoder on the call server.
So, when IKEA called from a random 1-877 number to confirm my furniture shipment worth $1200 (that's the equivalent of 
blåhaj!), the only thing it said is "To continue in English, please press 1."... and I had no idea who it was, immediately thought it was spam, and did the ### gesture. Oops.
What follows is a transcript of the call in the recording above.
Distorted voices and weird audio in this one, if that freaks you out.
The stack of effects on the clip is Maximus (an FL compressor, I think), Frequency Shifter, Parametric EQ, Delay and Convolver.