COMS W1004 Chapter Notes - Chapter 7: Wireless Wan, Wireless Lan, Media Access Control
3 May 2016
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Document Summary
Switched, dial-up telephone lines were the most common way to transmit in the early days of networking. Circuit is temporarily established between the caller and call recipient, and lasts only for the duration of the call. Originally an analog medium for transmitting human voice. Modem is device that modulates amplitude of carrier wave to binary signal 0"s and 1"s. Demodulation performs the inverse of the operation: bandwidth is rate at which information could be sent and received, broadband to day replaced modems and analog phone lines for all data communications. It is a communication link with transmission rate exceeding 256000 bps. Dsl and cable modems: digital subscriber line (dsl) uses same wires for telephone signals, different frequencies and transmits digital rather than analog signals. Asymmetric, not the same transmission speed downloading that uploading, so. Dsl provides greater bandwidth coming into your computer than going out: cable modem, use links that deliver cable tv signals, always on, speed comparable to.
