Originally Posted by
El_Duderito
Your assumption is wrong.
If you are interested you can learn about 'short stopping' here:
https://www.gsma.com/membership/reso...-destinations/
But the much more simple explanation is how phone networks actually work and the fact that they don't require a remote phone to be connected and/or ring to have the local phone play out a ring tone.
My wife worked in the North Tower of the World Trade Center. Sometime shortly after September 11, 2001 she told me to call her office phone. Yep, voicemail still working. I assume it was offsite somewhere but it was still creepy.