Extending the Subscriber Loop

In many situations, subscribers will reside outside of the maximum subscriber loop lengths described above. There are five generally accepted methods that can be used to extend these maximums. They are 1. Increase conductor diameter (covered above). 2. Use amplifiers and or range extenders.6 4. Use digital subscriber line (DSL) techniques (covered in Chapter 6). 5. Employ remote concentrators or switches (see Section 4.3). Amplifiers in the subscriber loop extend the transmission range. Perhaps...

Two Wire and Four Wire Transmission

A telephone conversation inherently requires transmission in both directions. When both directions are carried on the same pair of wires, it is called two-wire transmission. The telephones in our homes and offices are connected to a local switching center (exchange) by means of two-wire circuits. A more proper definition for transmitting and switching purposes is that when oppositely directed portions of a single telephone conversation occur over the same...

Regenerative Repeaters

Regenerative Repeater Block Diagram

As we are probably aware, pulses passing down a digital transmission line suffer attenuation and are badly distorted by the frequency characteristic of the line. A regenerative repeater amplifies and reconstructs such a badly distorted digital signal and develops a nearly perfect replica of the original at its output. Regenerative repeaters are an essential key to digital transmission in that we could say that the noise stops at the repeater. Figure 6.11 is a simplified block diagram of a...