>PSTN - Public switched telephone network. Think all of the hardline telephones. It's that entire network. Still in use as my grandmother can attest to. It's n

>PSTN - Public switched telephone network. Think all of the hardline telephones. It's that entire network. Still in use as my grandmother can attest to. It's not that simple anymore. Now it's frequently packetized after the last mile so PSTN is just an illusion provided as a service to your phone jack.