Introduction to Data Communications

Study Notes

Introduction to Data Communications

Data refers to any information presented in an agreed-upon format by communicating parties.
Data communications involve the exchange of data between devices using a transmission medium, such as wired or wireless connections.
A data communications system consists of both hardware (physical devices) and software (programs).

Characteristics of Data Communications Systems

Delivery: Ensures data reaches the intended recipient without being intercepted.
Accuracy: Guarantees data is transmitted without errors or corruption.
Timeliness: Ensures prompt delivery of data, crucial for real-time applications (e.g., video calls).
Jitter: Minimizes variability in packet arrival times to maintain smooth audio/video playback.

Components of a Data Communications System

Message: The data or information that is communicated.
Sender: The device responsible for transmitting the message.
Receiver: The device that receives the message.
Transmission Medium: The physical pathway for the message to travel (e.g., cables, wireless signals).
Protocol: The set of rules governing the communication process, representing an agreement between devices.

Forms of Messages

Text: Represented as bit patterns; coding systems like Unicode (using 32 bits) can represent text symbols.
Numbers: Directly converted to binary numbers for ease of mathematical operations, differing from text representation.
Images: Represented as bit patterns; composed of pixels whose count is determined by the resolution.
Audio: Involves sound recordings; characterized as continuous data rather than discrete.
Video: Involves moving images; produced as continuous or a combination of static images.

Data Flow Types

Simplex: Unidirectional communication; one device transmits while the other only receives (e.g., keyboards, monitors).
Half-Duplex: Devices can both transmit and receive but not simultaneously; only one device can send at a time (e.g., walkie-talkies).
Full-Duplex: Devices can transmit and receive simultaneously, similar to a two-way street (e.g., telephone networks).

Overview of Networks

A network is an interconnected set of devices capable of communication, including hosts (computers, phones) and connecting devices (routers, switches, modems).
Key network criteria include performance, reliability, and security.

Network Criteria

Performance: Affected by user count, transmission medium, hardware capabilities, and software efficiency. Measured by:
- Transit Time: Time taken for a message to travel between devices.
- Response Time: Time elapsed between an inquiry and the corresponding response.
Reliability: Assessed by failure frequency, recovery time from failures, and robustness under severe conditions.
Security: Entails protecting data from unauthorized access and ensuring safe communication protocols.

Description

Explore the essential concepts of data communications, including the critical characteristics and components of a communication system. Understand the roles of delivery, accuracy, timeliness, and jitter in ensuring effective data exchange. This quiz covers the foundations necessary for a solid understanding of how data is transmitted between devices.