TABLE OF CONTENTS The original development of Ethernet LANs was at a data rate of 10 Mbps, using two different types of coaxial cable media. As Ethernet technology evolved and LANs became an indispensable part of corporate networks, a demand for faster data transmission was initially solved by the use of different types of unshielded twisted pair (UTP) wiring. However, the use of UTP resulted in a distance constraint. To expand transmission distance, several types of fiber-optic repeaters were developed, which operated first at 10 Mbps and later at the Fast Ethernet data rate of 100 Mbps. Although such repeaters successfully extended the range of Ethernet networks, it was the development of Gigabit and 10 Gigabit networks that could use fiber as a transmission medium which provided both the high data rate and extended transmission distance required by many organizations. Although LEDs have been successfully used for several decades to extend the range of Ethernet and Fast Ethernet networks, unfortunately their maximum data rate with existing state-of-the-art technology is limited to 622 Mbps. Thus, although Gigabit and 10 Gigabit Ethernet networks cannot be driven through the use of LEDs at the present time, they represent a viable mechanism for extending the reach of other types of Ethernet networks.
In Section 5.2.1, we will commence our examination of the use of LEDs in Ethernet networks by briefly discussing how fiber-optic cable works. Once this is accomplished, we will describe and discuss the use of LEDs in certain types of Ethernet networking...
