Single made And Multi mode of Fiber Optic Cable

Single mode
In fiber-optic communication, a single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest. Single mode fibers are best at retaining the fidelity of each light pulse over longer distances and exhibit no dispersion caused by multiple spatial modes; thus more information can be transmitted per unit time giving single mode fibers a higher bandwidth in comparison with multi-mode fibers. A typical single mode optical fiber has a core radius of 5 to 10 µm and a cladding radius of 120 µm. Currently, data rates of up to 10 gigabits per second are possible at distances of over 60 km with commercially available transceivers.

Multi-mode optical fiber
(multimode fiber or MM fiber) is a type of optical fiber mostly used for communication over shorter distances, e.g. within a building. It can carry 1 Gbit/s for typical building distances; the actual maximum data rate (given the right electronics) depends upon the distance. Multi-mode fiber has a higher light-gathering capacity than single-mode optical fiber, making splicing less difficult, but its limit on speed × distance is lower. Because multi-mode fiber has a larger numerical aperture than single-mode fiber, it supports more than one propagation mode, resulting in larger modal dispersion and consequently higher pulse spreading rates, limiting information transmission capacity. Multimode fibers are useful for carrying larger amounts of power than single mode fibers. In such fibers, mode-filling becomes important, and mode scrambling attempts to fill the fiber to capacity, achieving an equilibrium mode distribution that utilizes all available fiber modes and has a more uniform energy density. These fibers are used when an intense beam is needed, as in optical pumping, laser welding, cutting, and marking.

Fiber Optic Cable

The transport fibres of glass or plastic that are enclosed by material of a lower index of refraction and that transmit light throughout their length by internal reflections. These fibres are bundled into cables and are capable of transmitting very large amounts of digital information (data) in both directions with very little loss in signal quality. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communication which permits transmission over longer distances and at higher data rates than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss, and they are immune to electromagnetic interference . Optical fibers are also used to form sensors and in a variety of other applications.
Light is kept in the "core" of the optical fiber by total internal reflection This causes the fiber to act as a waveguideFibers which support many propagation paths or transverse modes are called multimode fibers (MMF). Fibers which support only a single mode are called singlemode fibers (SMF). Multimode fibers generally have a large-diameter core, and are used for short-distance communication links or for applications where high power must be transmitted. Singlemode fibers are used for most communication links longer than 200 meters.
Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then spliced together either mechanically or by fusing them together with an electric arc.Special connectorsare used to make removable connections.

Ability to Assist Needs

It’s important to set objectives and be able to measure your progress. Successful managers establish specific measurements that tell them and others how well the organization is doing and provide feedback that helps managers zero in on issues that will improve the organization’s performance.

Answer..
Hard work and good intentions do not always achieve them. To achieve mission objectives, nonprofits and foundations must be able to define their strategy, analyze their progress and make improvements. The end result is a renewed focus on outcomes both for the organization and the beneficiaries of the organization’s mission.
This training will endow to upper management staff with the ability to craft a performance measurement and management system that links directly to your strategic goals and mission. After implementation of a performance measurement system, the key to an effective Performance management framework is for organizations to learn how to use the information provided from those measures to guide strategy, resources and execution.

PUNCH DOWN TOOL

A punch down tool, also called a punchdown tool or a Krone tool is a small screw-driver sized tool used for connecting wiring to a punch down block. The tool consists of a handle with a spring mechanism inside and at the tip a small square piece of metal with a square hole in it. To use the punch down tool, a wire is inserted in between the two metal blades on a punch down block and the punch down tool is pressed down on top of the wire and the two blades on the punch down block. This requires a bit of pressure until with an audible snap the wire is stripped and contact made as it is pushed down between the two punch down block blades.

PATCH PANEL

A patch panel or patch bay is a panel, typically rackmounted, that houses cable connections. One typically shorter patch cable will plug into the front side, while the back will hold the connection of a much longer and more permanent cable. The assembly of hardware is arranged so that a number of circuits, usually of the same or similar type, appear on jacks for monitoring, interconnecting, and testing circuits in a convenient, flexible manner.
Patch panels offer the convenience of allowing technicians to quickly change the path of select signals, without the expense of dedicated switching equipment. This was first used by early telephone exchanges, where the telephone switchboard (a massive array of patch panels) and a large room full of telephone operators running it was ubiquitous.

Different between the CSMA/CD to CSMA/CA

CSMA/CD (Carrier Sense Multiple Access / Collision Detection) is the protocol used in Ethernet networks to ensure that only one network node is transmitting on the network wire at any one time. Carrier Sense means that every Ethernet device listens to the Ethernet wire before it attempts to transmit. If the Ethernet device senses that another device is transmitting, it will wait to transmit. Multiple Access means that more than one Ethernet device can be sensing (listening and waiting to transmit) at a time. Collision Detection means that when multiple Ethernet devices accidentally transmit at the same time, they are able to detect this error.

CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance), a network contention protocol that listens to a network in order to avoid collisions, unlike CSMA/CD that deals with network transmissions once collisions have been detected. CSMA/CA contributes to network traffic because, before any real data is transmitted, it has to broadcast a signal onto the network in order to listen for collision scenarios and to tell other devices not to broadcast.