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Traditional Telephony VoIP and PoE Voice over IP is a network-based telephone service. Since VoIP doesn’t derive it’s power from the telephone company central office, other means of backup power are needed. Power Over Ethernet was originally intended to provide VoIP with a source of backup power. It simulates the traditional telephone’s availability during power outages and provide 911 service at all times. PoE-IEEE 802.3af provides 48Vdc power over 2 of 4 available pairs on Category UTP cable. After line loss, about 13W of power are available VoIP and Fiber VoIP and PoE are complimentary but they are not codependent.

Application Whether in fixed telephone networks or in the field of mobile telephony (with the new 3G systems), traffic in the network is constantly increasing. With more and more information being transported at higher and higher data speeds, synchronization of traffic in networks is becoming increasingly important. How can you verify that your network is synchronized? And what are the consequences if it is not? Synchronization of SDH Networks Telecommunications’ reliability is based on data signals being synchronized and clocked using the same clock throughout the network. The basic clock in European telecom networks (SDH, or Synchronous Digital Hierarchy networks)

Overview With the fiber optics revolution for telecommunications in the 1980s, fiber optical technology became increasingly more advanced and higher quality. The telecommunications boom in the late 1990’s resulted in a dramatic boost to the technical capability of fiber optical technologies and associated optoelectronics. Radical improvements were made in superb quality, very long lifetime, and reduced price for many components: pump diode lasers, coupling, beam combiners, rotators, Bragg fiber filters, modulators, and detectors. Also, the fibers themselves have seen significant innovation over the last decade, with commercial availability of larger cores for higher power, double-clad fibers for multimode pumping, producing

Pulse Spreading The data which is carried in an optical fiber consists of pulses of light energy following each other rapidly. There is a limit to the highest frequency, i.e. how many pulses per second which can be sent into a fiber and be expected to emerge intact at the other end. This is because of a phenomenon known as pulse spreading which limits the “Bandwidth” of  the fiber.The pulse sets off down the fiber with an nice square wave shape. As it travels along the fiber it gradually gets wider and the peak intensity decreases. Cause of Pulse Spreading

Reflection and Refraction of Light When light travelling in a transparent material meets the surface of another transparent material two things happen 1. some of the light is reflected 2. some of the light is transmitted into the second transparent material The light which is transmitted usually changes direction when it enters the second material. This bending of light is called refraction and it depends upon the fact that light travels at one speed in one material and at a different speed in a different material. As a result each material has its own Refractive Index which we use to