If you started a call with your cellphone close to a loudspeaker you could hear the connection being initiated through the speaker. Something like a tat-ara-tat sound.
Oh yeah. I totally forgot about that. Why did that stop? Phones started using different frequencies or something?
It’s actually a change in audio equipment. If you have old speakers you can still hear it.
I think they made a song with that noise, something dance or techno or house
Mario Piu - Communication?
https://youtu.be/CGHKb5LSKE0?si=zGhmQNtJoLRcaDyp&t=55
“They” probably made a bunch, but I’d recommend you to check out Venjent - Calling for You (ft. Oktae) (and anything else from him tbh).
some GSM phones would reboot PCs if a call came through and was situated near the PC.