Andres Torre
Lab 4:
4.1.1: Stability, Consistency, Minimization of packet errors.
4.1.2: Because the voltage (or current) used to transmit data needs only be high enough for the receiver to detect it. Making the voltage (much) higher would make the receiver electronics more difficult.
4.1.3: A shielded cable is an electrical cable of one or more insulated conductors enclosed by a common conductive layer. The shield may be composed of braided strands of copper (or other metal, such as aluminium), a non-braided spiral winding of copper tape, or a layer of conducting polymer. Usually, this shield is covered with a jacket. The shield acts as a Faraday cage to reduce electrical noise from affecting the signals, and to reduce electromagnetic radiation that may interfere with other devices (see electromagnetic interference). The shield minimizes capacitively coupled noise from other electrical sources. The shield must be applied across cable splices.
4.1.7: Short for unshielded twisted pair, a popular type of cable that consists of two unshielded wires twisted around each other. Due to its low cost, UTP cabling is used extensively for local-area networks (LANs) and telephone connections. UTP cabling does not offer as high bandwidth or as good protection from interference as coaxial or fiber optic cables, but it is less expensive and easier to work with.
4.2.1: In fiber-optic communication, a single-mode optical fiber (SMF) is an optical fiber designed to carry only a single ray of light (mode). Modes are the possible solutions of the Helmholtz equation for waves, which is obtained by combining Maxwell's equations and the boundary conditions. These modes define the way the wave travels through space, i.e. how the wave is distributed in space. Waves can have the same mode but have different frequencies. This is the case in single-mode fibers, where we can have waves with different frequencies, but of the same mode, which means that they are distributed in space in the same way, and that gives us a single ray of light. Although the ray travels parallel to the length of the fiber, it is often called transverse mode since its electromagnetic vibrations occur perpendicular (transverse) to the length of the fiber. The 2009 Nobel Prize in Physics was awarded to Charles K. Kao for his theoretical work on the single-mode optical fiber.[1]
4.2.2: Why Fiber Optic cables over copper?

1 Fiber Optic is so much more efficient and secure than copper cabling. In comparison, Fiber Optic cables can transmit far more information, and with a greater degree of fidelity. In fact, fiber links offer over 1,000 times as much bandwidth over distances over 100 times further than copper. Fiber Optic cabling also offers extra security for the data being transmitted, since it is far more difficult to tap than copper cable.

2 Only Fiber Optics can go the distance. Not only is Fiber Optic cable capable of carrying far more data than copper, it also has the ability to carry that information for much longer distances. Indeed, a Fiber Optic cable can easily transmit a signal as far as 80 km or more without the need for amplification.

3 Fiber Optics can't be interfered with! Because Fiber Optic cables are glass-based, they don't conduct electricity. This eliminates the need for grounding, and makes them immune to any type of electrical interference - even lightning. Since Fiber Optic cabling is so resistant to interference and atmospheric conditions, it can be used outdoors - and in close proximity to electrical cables - without concern.

4 Fiber Optic cables don't mind roughing it. Glass fibers don't only escape interference but they are also virtually free from the threat of corrosion, too! While copper cabling is sensitive to water and chemicals, Fiber Optic cabling runs almost no risk of being damaged by harsher elements. As a result, Fiber Optic cables can easily endure living conditions that coaxial cable just cant, such as being put in direct contact with soil, or in close proximity to chemicals.

5 You may be surprised by Fiber Optics, but you won't be shocked. A major benefit of Fiber Optic cabling is that it doesn't pose a threat of physical injury to the user if it breaks. Since Fiber Optic cabling transmits light and not electricity, the people handling it run no risk of injury from fire, sparking or electrocution.

Fiber Optic cabling has advantages over standard copper coaxial cables, in that it can transmit larger quantities of data with far less loss, is able to maintain signals over long distances, carries little risk of corrosion, and is virtually free from interference.