Chapter 2.3 part 1
- 1. Chapter 2.3
- 2. Telecommunications Communication of information by electronic means Telecommunications System Components Computers to process information Terminals that send or receive data Communications processors Communications software
- 3. Functions of Telecommunications Systems Transmit information Establish network between receiver and sender Route messages Perform elementary processing Perform editorial tasks Convert message speed or format Control flow
- 4. Types of Signals: Analog and Digital Analog Signal Continuous waveform Passes through communications medium Used for video and audio communications Digital Signal Discrete waveform Transmits date coded into two discrete states Used for data communications Modems translate computer´s digital signals into analog and vice versa
- 5. Communication Channels Wired Transmission Twisted wire: Telephone systems Coaxial cable: cable television Fiber optics: Dense wave division multiplexing (DWDM) Wireless Transmission Microwave, Satellites, Cellphones Hertz Use 10^8-10^10 = cellular phones and mobile date networks 10^10-10^12 = microwaves (GRPS,GMS, 3rd generation, 3G) 10^13-10^14 = Wireless Media 10^15-10^16 = Fiber optics (visible area, from red to violet)
- 6. Communications Processors and Software Front-end processor: manages communications for host computer Concentrator: collects and stores messages Controller: supervises communication traffic Multiplexer: Enables single communication channel to carry data transmissions
- 7. Network Topologies Three different types of networks Star Network: all computers are connected to central host computer Bus Network: links computers by a single circuit Ring Network: all computers linked by a loop
- 8. LANs, WANs, VANs LAN (Local Area Network) Requires own channel Enclosed in a limited distance Gateway, router, Network Operating System WAN (Wide Area Network) Large distance span Consists of cable, satellite, and microwave technologies VAN (Value-Added Network) Private, multi-path, data only, third-party-managed
- 9. Electronic Commerce and Electronic Business Technologies Three different types of conferencing Teleconferencing: ability to talk with various people at the same time Data conferencing: two or more edit data files at the same time Videoconferencing: users can see each other on screens Electronic Data Interchange Direct exchange between organizations Customer can purchase orders or process payments Seller can provide shipping, price updates and invoices