Data Communication and Computer Networks Vocabulary

Vocabulary flashcards defined verbatim from the Chapter 4 lecture notes on Data Communication and Computer Networks.

Data

Raw, unprocessed facts or information related to any object prior to sorting, arranging, or processing.

Data Communication

The complete setup and process of transferring data from a sender (person or device holding data) to a receiver.

Data Transmission

The technical term for sending data from a transmitting device across a medium to a receiving end.

Analog Signals

Continuous physical signals that vary continuously without a fixed range, representing physical quantities like sound, light, pressure, and temperature.

Digital Signals

Discrete signals generated using electrical on and off pulses (0 and 1) displayed in square or block wave formats.

Sine Waves

The continuous wave format used to visually represent analog signals.

Square Waves

The block wave format used to visually represent digital signals.

Data Rate (Bit Rate)

A unit of measurement in data communication calculated as the number of bits (0s and 1s) transferred per second.

Baud Rate

A unit of measurement in data communication that quantifies the number of signal changes or signal transmissions per second.

Signal-to-Noise Ratio (SNR)

A property of communication systems measuring the ratio of the transmitted signal relative to background noise.

Message

The specific data or information that needs to be transferred or communicated within a communication system.

Sender

The device or entity that transmits or sends the message in a communication system.

Receiver

The target device or entity that receives the transmitted message in a communication system.

Communication Medium

The physical path or wireless route through which data travels from the sender to the receiver.

Protocols

The rules, procedures, uniform codes, and programs that govern and enable data exchange between communicating devices.

Delivery

A fundamental requirement of a good communication system stating that transmitted data must successfully reach its intended destination.

Accuracy

A property of a good communication system ensuring data is delivered precisely to the correct designated address.

Timeliness

A property of a good communication system ensuring data is delivered within the expected or required timeframe.

Guided Medium

Wired communication channels, such as twisted pair, coaxial, and fiber optic cables, that physically connect devices.

Unguided Medium

Wireless communication channels that transfer signals through the air as electromagnetic waves without physical wires.

Twisted Pair Cable

A guided medium composed of thin copper wires twisted around each other to reduce noise and distortion.

Unshielded Twisted Pair (UTP)

A lower-cost twisted pair cable without extra shielding, optimal for small local area networks (LANs).

Shielded Twisted Pair (STP)

A twisted pair cable featuring an extra protective layer against outside interference and noise, used for broader networking like cable net services.

Coaxial Cable

A guided medium containing a central copper wire surrounded by insulating layers for high noise reduction, commonly used in television transmissions.

Fiber Optics Cable

The fastest guided media made of glass fibers that transmit data as light signals with minimal resistance.

Radio Waves

Omnidirectional wireless waves that easily pass through physical obstacles and travel in all directions.

Omnidirectional Signal

A signal that spreads outward in all directions simultaneously from a sending antenna.

Micro Waves

Directional wireless waves that travel line-of-sight in a single direction at a specific aligned angle.

Terrestrial Microwaves

Microwave communication systems where both sending and receiving antennas or towers are situated on Earth.

Satellite Microwaves

Microwave transmission systems that relay signals between Earth stations using orbiting satellites in space.

Infrared Waves

Weak, short-range wireless signals that cannot penetrate walls and rely on LEDs and photodiodes to transmit data.

Transmission Impairments

Defects or anomalies in a communication system causing the received data to differ from the original transmitted data.

Signal Attenuation

A transmission impairment where a signal loses energy as it travels through a medium, requiring amplifiers or boosters.

Distortion

A transmission impairment characterized by a change in the shape of a composite signal when its different frequency components arrive out of sync.

Noise

Any unwanted external signal that interferes with and degrades the quality of the original signal.