N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 2 - Data Communications Basics and Legacy Technologies                                                Slide 15 of 45 _________________                                                                                  __________

               Building Blocks - Transmission Media and Their Capabilities

                                                Copper Wire

                                                Coax Cable

                                                Optical Fiber

                                                Micro Waves

_________________                                                                                  __________

There are two types of physical media to carry data: bounded and unbounded. In bounded channel signals are confined to the medium except leakage of the signal and do not leave the medium. The examples of bounded medium are a pair of copper wire, coax cable and optical fiber. The atmosphere, the ocean and outer space are the examples of the unbound media (channels), where signals (electromagnetic) generated by the source radiate into the medium and spread throughout medium.

A Pair of Copper Wire - Most common type of medium used by the PSTN and for wiring within buildings. The wiring comes in 19, 22, 24 and 26 loaded (with coils to reduce signal loss) and unloaded for high speed data transmission. This medium used to carry data at 1.544 M bps and 45 M bps.

A Coax Cable - A copper wire suspended by insulation in the center of a copper tube used for transmitting TV signals and Internet signals is capable of transmitting up to 350 M bps.

Optical Fiber - A dielectric wave guide made of glass or plastic. The fibers comes in two types: Single Mode and Multi-Mode. The optical fiber guides light rays within the fiber material. With the latest progress in optical fiber technology tera bps data can be transmitted through a fiber.

Microwave - Waveguides are used to transmit microwave signals at G Hz frequencies. The fixed wireless systems are capable of transmitting in 50 - 60 M bps range. The satellite systems are capable of carrying TV, Voice and data signals.