Page 63 - DCAP406_DCAP_207_Computer Networks

Computer Networks/Networks

Notes
Figure 4.7: Cellular Network Connection to Telephone Exchange

The forward cell can reuse frequencies used in the previous cell. This helps in sharing the same
frequency band. Many calls can be handled by one frequency especially where digital phones
are used.

4.5 Cable Television

Cable television or Cable TV uses coaxial cable as the transmission media to transmit television
programs to televisions at home or office. Conventional television uses over-the-air broadcasting
of signal using radio waves to transmit television programs to television receivers. This system
requires a television antenna. On the other hand, cable television system uses radio frequency
signals over fixed optical fibers or coaxial cables to transmit television programs to the consumers.
Other applications of cable television are FM radio programming, high-speed Internet, telephony,
etc.

Did u know? Using coaxial cables provide several advantages because of its huge bandwidth;
transmission of bi-directional signal and large amounts of data is possible. Cable television
signals require small bandwidth of coaxial lines. Hence, remaining bandwidth may be
used for other digital services such as broadband Internet and cable telephony.
Broadband Internet over Coaxial Cable: It is possible because of cable modems that convert the
internet data into digital signal that can be transferred over coaxial cable.
Cable Telephone Services: A special telephone interface is installed at the customer’s premises to
convert the analog signals from the customer’s in-home wiring into a digital signal. The analog
signal is then sent on the local loop to the switching center. Its advantages include need of less
bandwidth, better voice quality and integration to a VoIP network.
Cable Modem
Cable modem works on the principle of modems and provides access to data signal sent through
the cable television infrastructure. Cable modems delivers broadband Internet access in the
form of cable Internet, taking advantage of unused bandwidth on a cable television network
using coaxial cable or optical fiber cable. A cable modem works like a bridge in accordance with
IEEE 802.1D for Ethernet networking. The cable modem forwards Ethernet frames between a
customer LAN and the coaxial cable network.

Task Give a brief description of the application and limitations of the wireless
communication and compare it with bounded transmission media.

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