PSTN-Public Switched Telephone Networks
PSTN. The POTS - Plain Old Telephone System or PSTN - Public Switched Telephone Network is the analog phone lines that are installed in most residences and businesses. It has two big advantages.
- it is available almost all over the world
- it is relatively inexpensive
- Using the existing telephone infrastructure to implement computer networking should make sense. Just about all that is required is a modem, to bridge the gap between digital computers and analog telephone lines, which are basically commodities.
Unfortunately, the original phone lines were not intended to carry the data rates required for many modern computer uses. This implies there are inherent limits to their capacity. Even with 56 Kbps modems, the capacity of many lines is 40 Kbps to 45 Kbps. The quality of the lines and transmissions is also a factor.
