Telecommunications Essentials

The PSTN Versus the Internet

In one very important fashion, the PSTN and the public Internet are one and the same thing: they both exist on the same physical infrastructure. There would be no Internet without the PSTN. The communications links, or backbones, that ISPs run on are delivered over the PSTN, and the access lines for entry into the Internet are all subscriber lines that are part of the PSTN. But what differentiates the PSTN and the Internet is the equipment that's attached to each network, its use, and how it formats the information it carries.

PSTN Characteristics

The PSTN basically includes telephones, fax machines, and circuit switches that set up continuous but temporary connections. In a PSTN environment, the circuit is established ...