Page 138 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Unit 6: Data Communication

• A modem is a device that modulates an analog carrier signal to encode, digital information, Notes
and also demodulates such a carrier signal to decode the transmitted information.
• Wireless network refers to any type of computer network that is not connected by cables
of any kind.
• Wireless telecommunication network are generally implemented and administered using
a transmission system called radio waves.
6.7 Keywords

Computer networking: A computer network, often simply referred to as a network, is a collection of
computers and devices interconnected by communications channels that facilitate communications
among users and allows users to share resources. Networks may be classified according to a wide
variety of characteristics.

Data transmission: Data transmission, digital transmission, or digital communications is the
physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint
communication channel.
Dial-Up lines: Dial-up networking is an important connection method for remote and mobile users.
A dial-up line is a connection or circuit between two sites through a switched telephone network.
DNS: The Domain Name System (DNS) is a hierarchical naming system built on a distributed
database for computers, services, or any resource connected to the Internet or a private network.
DSL: Digital Subscriber Line (DSL) is a family of technologies that provides digital data
transmission over the wires of a local telephone network.
GSM: Global System for Mobile Communications, or GSM (originally from Groupe Spécial Mobile),
is the world’s most popular standard for mobile telephone systems.
ISDN Lines: Integrated Services Digital Network (ISDN) is a set of communications standards
for simultaneous digital transmission of voice, video, data, and other network services over the
traditional circuits of the public switched telephone network.
LAN: A local area network (LAN) is a computer network that connects computers and devices in
a limited geographical area such as home, school, computer laboratory or office building.
MAN: A metropolitan area network (MAN) is a computer network that usually spans a city or
a large campus.
Modem: A modem (modulator-demodulator) is a device that modulates an analog carrier signal to
encode digital information, and also demodulates such a carrier signal to decode the transmitted
information.

Network topology: Network topology is the layout pattern of interconnections of the various
elements (links, nodes, etc.) of a computer network.

PSTN: The public switched telephone network (PSTN) is the network of the world’s public
circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave
transmission links, cellular networks, communications satellites, and undersea telephone cables
all inter-connected by switching centers which allows any telephone in the world to communicate
with any other.
VPN: A virtual private network (VPN) is a computer network that uses a public telecommunication
infrastructure such as the Internet to provide remote offices or individual users secure access to
their organization’s network.

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