Transcript Week 1
Week 1 Things you want to know Week 1 • This is a series of things you want to know as you walk away from the course. • What elements make up a communication system? • How do we classify communications systems? • Give examples of each switching technology. • Describe telecom standards bodies, give examples of standards. • What are the two types of standards? Elements of a Communication System • Source - the originator of the message, whether it is a person or machine. • Transmitter - the equipment that modifies the message (either data or voice) into the form required for transmission. • Communications channel - the means of carrying the signal from the source to the destination. Elements of a Communication System • Transmission media - may be physical, like a copper wire or fiber optic cable, or atmospheric, like radio waves. • Receiver - is the device that captures the message from the communications channel and converts it into a form that the person or machine at the destination can understand. • Destination - the person or machine to whom the message is directed Elements of a Communication System Flow of Messages • Simplex - the type of communication in which messages flow in only one direction, from source to destination. • Half-duplex communication - occurs when messages travel in both directions between the source and the destination, but in only one direction at a time. • Full-duplex communication - messages can travel over the communications channel in both directions simultaneously. Flow of Messages Relative Number of Sources and Destinations • One-to-one communication - a single source sends information to a single destination. • One-to-many communication - a single source simultaneously sends information to multiple destinations. • Many-to-many communication - occurs when many sources issue messages to many destinations. Relative Number of Sources and Destinations Classification of Data Networks by Ownership • Public Network – Owned by a common carrier • Private Network – Built for exclusive use by a single organization • Virtual Private Network – Encrypted tunnels through a shared private or public network 10 Classification of Data Networks by Switching Technology • Circuit Switching – Connection-oriented networks, ideal for realtime applications, guaranteed quality of service • Message Switching – Store-and-forward system • Packet Switching – Shared facilities, Used for data communications • Cell Switching – Fast processing of fixed length cells 11 Classification of Data Networks by Computing Model • Distributed Computing – Client/Server set-up • Centralized Computing – Thin-client architecture • Some Useful Telecom Terms – Scalability: Ability to increase the power and/or number of users without major redesigns – RAID (Redundant Array of Independent Disks) – UPS (Uninterruptible Power Supply) 12 Classification of Data Networks by Type of Information • Data Communications – Digital transmission of information • Voice Communications – Telephone communications • Video Communications – Cable TV or video conferencing 13 ANSI • The ANSI (American National Standards Institute) - an organization composed of over a thousand representatives from industry and government who together determine standards for the electronics industry. • ANSI does not dictate that manufacturers comply with their standards, but requests them to voluntarily comply. TIA and EIA • The EIA (Electronics Industry Alliance) - is a trade organization composed of representatives from electronics manufacturing firms across the United States. • TIA (Telecommunications Industry Association) - focuses on standards for information technology, wireless, satellite, fiber optics, and telephone equipment. IEEE • IEEE (Institute of Electrical and Electronic Engineers) - an international society composed of engineering professionals. • Its goals are to promote development and education in the electrical engineering and computer science fields. ATIS • ATIS (The Association for Telecommunications Industry Solutions) - a North American trade association made of thousands of companies that provide communications equipment and services. • Its membership reviews emerging technology and agrees on standards and operating procedures to ensure that services and equipment supplied by multiple companies can be easily integrated. ISO • ISO (International Organization for Standardization) - a collection of standards organizations representing 130 countries with its headquarters located in Geneva, Switzerland. • Its goal is to establish international technological standards to facilitate global exchange of information and barrier-free trade. ITU • The ITU (International Telecommunications Union) - a specialized United Nations agency that regulates international telecommunication usage, including radio and TV frequencies, satellite and telephony specifications, networking infrastructure, and tariffs applied to global communication. • Provides developing countries with technical expertise and equipment to advance their technological base. Standards • De facto Standards • Open Computing Week 1 Links • • • • • • www.privateline.com/TelephoneHistory/History1.htm www.bellsystemmemorial.com/westernelectric history.html www.bellsystemmemorial.com/bellsystem history.html www.tecomhistory.org www.museumphones.com/index.html#t www.althosbooks.com