, which is precisely what happens to light waves if they reflect, or "bounce," off the inner wall of the fiber strand as they travel. These zigzag paths also cause the signals to attenuate, lose power, and fade over shorter distances. The narrow core results in a narrower angle of acceptance. The small angle of acceptance of single-mode fiber keeps the light signal from bouncing across the diameter of the fiber's core. Thus, the straighter light signal travels faster and has less attenuation than if it had a bouncier ride through the core. When the light pulses travel in narrower paths, fewer amplifiers are needed to boost the signal. Single-mode fiber can be run for 49 to 74 miles without amplification (boosting). In contrast, signals on copper cabling need to be amplified after approximately 1.5 miles. For this reason, telephone companies originally used fiber for outside plant cabling with cable runs longer than 1.2 miles. However, the demand for higher capacity and the lower maintenance costs have resulted in carriers running increasing amounts of fiber cabling directly to homes and buildings. www.TechnicalPDF.com The main factor in the increased expense of single- mode fiber is the higher cost to manufacture more exact connectors for patch panels and other devices. The core is SO small that connections and splices require much more precision than does multi-mode fiber. If the connections on single-mode fiber do not match cores exactly, the light will not be transmitted from one fiber to another. It will leak or disperse out the end of the fiber core at the splice. Multi-mode fiber has a wider core than single-mode fiber. The wider core means that signals can only travel a short distance before they require amplification. In addition, fewer channels can be carried per fiber pair when it is multiplexed because the signals disperse, spreading more across the fiber core. Multi-mode fiber is used mainly for LAN backbones between campus buildings and between floors of buildings. Another factor in the expense of in