This refers to a detectable physical quantity or impulse (as a voltage,current, or magnetic field strength) by which messages or information can be transmitted via telegraphy, telephony, radio, radar, or television.

Electronics Transmitted Information

(voltages and currents in a circuit)

Electrical Signals

(audio or speech signals)

Acoustic Signals

(intensity variations in an image)

Video Signals

(sequence of bases in a gene)

Biological Signals

(interference – unwanted and undesired form of signal)

Noise

refer to disturbances in that energy to travel through a medium from one location to another.

Wave

refers to the horizontal distance of a wave from a point to the corresponding point on the next wave. This is measured in meters (m) in SI.

Wavelength

It refers to a vertical distance from a given point on the wave from the horizontal axis. In layman’s terms, it is the height above and below the x-axis.

Amplitude

It describes the position of the waveform relative to time zero; it is a measurement of the delay of the wave relative to some fixed reference point or another sine wave.

Phase

It refers to the number of waves made per second or as cycles per second.

Frequency

This refers to the amount of time (expressed in seconds) required to complete one (1) full cycle.

Period

It is a wave in which both the amplitude and time continuously vary over their respective intervals that results in a wavy characteristic. Examples of this wave include the human voice and music.

Analog Wave

It is a wave with several discrete (jumpy) states, such as high or low, and on or off. It hasfixed amplitude, but its pulse width and frequency can be changed.

Digital Wave

These networking media use cables and are limited by physical geography.

Wired or Bounded Media

In contrast to wired or bounded media, these networking media do not use any cables in transmitting data and is not bounded by physical geography

Wireless or Unbounded Media

is a connection wherein data flows in one (1) direction only (unidirectional).

Simplex Mode

is a connection wherein data can flow in both directions, but notsimultaneously (both at the same time) over a shared physical medium.

Half-Duplex Mode

is a connection wherein data simultaneously flows in both directions

Full-Duplex Mode

is a transmission in which data with each bit lining up in a series as the bits are sent over a single wire at a time.

Serial Transmission

is a transmission wherein a group of bits is sent simultaneously, but each uses a different channel.

Parallel Transmission

The most widely used standard for serial data communications is which is intended to operate over distances of up to 50 feet and has a communication speed that is equal to or less than 20Kbps.

Serial Cable

refers to two (2) conductors enclosed by an insulating protective coating.

Coaxial Cable

consists of two insulated strands of copper wire that are arranged in a regular spiral pattern

Twisted Pair Cable

refers to a bundle of extremely thin and cylindrically shaped glass fibers surrounded by a concentric layer of glass coating that can conduct modulated light transmissions

Fiber Optic Cable

refers to the innermost section that consists of one (1) or more very thin strands or fibers made of glass or plastic.

Core

refers to an outer optical glass or plastic coating that surrounds and traps the light in the core by the principle of total internal reflection.

Cladding

is made from plastic that helps to shield the core and cladding from damage

Coating

stand as protection for the core against compressive forces or crushing and tension or excessive pulling.

Strengthening Fibers

refers to an outermost layer that protects a buffer or a bundle of buffer- coated fibers against moisture, abrasion, crushing, and other environmental dangers.

Cable Jacket

This fiber optic cable type allows light waves to travel along a single path or in only one mode. It is used for high-speed transmission over long distances.

Single mode fiber optic cable

This fiber optic cable type allows light waves to travel into numerous paths through the core of the fiber at various angles. It is often applied to local area networks which encompass a much smaller transmission range.

Multimode fiber optic cable

It is a method by which radio waves travel from the transmitting antenna to the receiving antenna.

Line of Sight Propagation

It is a method by which radio waves are radiated directly towards the earth’s surface.

Ground Wave Propagation

It is a method by which radio waves radiate upwards from the transmitting antenna of the earth into a direction towards the ionosphere

Skywave Propagation

It is a method by which radio waves radiation exceeds 30 MHz up to 300 GHz.

SpaceWave Propagation

refers to a wireless medium that is used for short-range communication (e. g. remote control devices, intruder alarms, infra-red photography, and radiant heaters) in a closed area using line-of-sight propagation.

Infrared

refers to a wireless medium that is used for unicast communication such as wireless PAN (Bluetooth), broadband wireless access or wireless MAN (WiMAX), wireless WAN (2G/3G cellular networks), satellite networks and radar, and wireless LANs (Wi-Fi).

Microwave

is a short-range wireless communication technology that allows devices such as mobile phones, computers, and peripherals to transmit data or voice wirelessly over a short distance.

Bluetooth

in this type of topology, the computers are connected to a single hub through a cable. This hub is the central node while all other nodes are connected to it.

Star Topology

a network type in which every computer and network device is connected to a single cable

Bus Topology

forms a ring as each computer is connected to another computer, with the last one (1) connected to the first—exactly two (2) neighbors for each device.

Ring Topology

has a root node and all other nodes are connected to it forming a hierarchy.

Tree Topology

a point-to-point connection to other nodes or devices. All the network nodes are connected.

Mesh Topology

it consists of a mix of two (2) different types of topologies merging as one network.

Hybrid Topology

It is the end-device of the data communication system. It provides the necessary functions required by the user access protocol operations.

Terminal Device

It is a schematic description of a network arrangement, connecting various nodes (sender and receiver) through lines of

Network Topologies

It is the device closest to end-users, used to access the network and switch data frames.

Switch

It is a network-layer device that forwards data packets on the Internet.

Router

It is a network security device used to ensure secure communication between two networks.

Firewall

It generally covers an area of a few square kilometers.

Local Area Network

It is a large-sized LAN, requiring high costs but can provide a higher transmission rate.

Metropolitan Area Network

It generally covers an area of several kilometers or larger

Wide Area Network

is a descriptive network scheme. The OSI model describes how information or data makes its way from application programs through a network medium to another application program located on another network.

Open Systems interconnection (ISO) Model

It is a networking model with a set of communication protocols for the Internet and similar networks.

TCP/IP model

Which Statement is FALSE in Comparison of OSI Reference Model to TCP/IP Model

OSI model is developed by ISO (International Standard Organization), whereas TCP Model is developed by Microsoft (Advanced Research Project Agency Network).

In ISO Model, It is the OSI layer that is closest to the user.

Application Layer

In ISO Model, It ensures that the information that the application layer of one (1) system sends out is readable by the application layer of another system.

Presentation Layer

In ISO model, It defines how to start, control and end conversations (called sessions) between applications

Session Layer

In ISO model, it regulates information flow to ensure end-to-end connectivity between host applications reliably and accurately.

Transport Layer

In ISO model, It defines end-to-end delivery of packets.

Network Layer

In ISO model, It provides access to the networking media and physical transmission across the media and this enables the data to locate its intended destination on a network.

Data Link Layer

In ISO Model, deals with the physical characteristics of the transmission medium

Application Layer