The Telephone Network
A network is a series of interconnections that when all tied together form a cohesive and ubiquitous connectivity arrangement.
Whew! That sounds ominous, but to make this a little simpler, look at the components of what constitutes the telephone network. Generally, a network is a series of interconnection points. The telephone companies over the years have been developing the connections throughout the country and the world, so that a level of cost-effective service can be provided to its customers.
In order to build out this connectivity, the telephone companies install wires to the customer’s door, whether business or residential. The spot where these wires terminate is called the demarcation point. The position of the demarcation point depends on the legal issues involved. In the beginning days of the telephone network, the telephone companies owned everything, so they ran the wires to an interface point, then connected their telephone sets to the wires at the customer’s end.
This was the cradle to grave service that allowed them to proliferate the connections throughout their entire operating area. New regulation in the United States, in effect since the divestiture agreement changed this connection to a point at the entrance to the customer’s building. From there, the customers hook up their own equipment, items they purchase from a myriad of other sources. In the rest of the world, where full divestiture has not yet taken place, the telephone companies (or PTTs) still own the equipment.
Other areas of the world have a hybrid system, where customers might or might not own their equipment. The combinations of this arrangement are almost limitless, depending on the degree of privatization and deregulation. However, the one issue that is common in most of the world to date, the local provider owns the wires from the outside world to the entrance of the customer’s building.
This introduction is meant to teach you about the functions and technology of a Central Office.
Analog to Digital Bandwidth
The Telephone Network
A Topology of Connection
Network Hierarchy (pre 1984)
Network Hierarchy (post 1984)
North American Numbering Plan
The Subscriber Extension
Local Access and Transport Areas
Wiring Connections: Hooking Things Up
Types of Communication
Lines Vs. Trunks
Foreign Exchange Signal