This document discusses the history and technologies of telecommunications and computer networking. It covers topics such as Morse code, the development of the telegraph and telephone, early computers, transmission media including twisted pair cable, coaxial cable, fiber optics, microwave, and satellite. It also defines related terms such as bandwidth, broadband, modem, multiplexer, and communications processor.

1. PRESENTED BY: CUETO, KENJIE

3. High speed data exchange between computers
and/or other electronic devices via cable or
wireless.

6. A code developed by Samuel
Morse used for transmitting
messages in which letters of the
alphabet and numbers are
represented by various sequences
of written dots and dashes, or
short and long signals such as
electric tones or voltages. Morse
code was used extensively in
telegraphy. In a format that has
been standardized for
international use, it is still
sometimes used for long distance
radio communication.

7.  By 1851, more than fifty
telegraph companies were in
operation.
 In 1874, a Frenchman Emile
Baudot invented a telegraph
multiplexer and developed a
code suitable for machine
encoding and decoding.

8.  In1876 telephone
was invented by Dr.
Alexander Graham
Bell. Founder of the
Bell Telephone
Company by the year
of 1877.

9.  (Universal Automatic Comp
uter) The first commercially
successful computer,
introduced in 1951 by
Remington Rand. Over 40
systems were sold. Its
memory was made of
mercury-filled acoustic
delay lines that held 1,000
12-digit numbers. It used
magnetic tapes that stored
1MB of data at a density of
128 cpi.

11. A medium through which a message is transmitted
to its intended audience, such as print media or
broadcast (electronic) media.

13.  A type of cable that consists of two
independently insulated wires
twisted around one another. The use
of two wires twisted together helps
to reduce crosstalk and
electromagnetic induction. While
twisted-pair cable is used by older
telephone networks and is the least
expensive type of local-area
network (LAN) cable, most
networks contain some twisted-pair
cabling at some point along the UTP CAT. 5E
network. Other types of cables used
for LANs include coaxial
cables and fiber optic cables.

15.  Coaxial cabling is the primary
type of cabling used by the
cable television industry and is
also widely used for computer
networks, such as Ethernet.
Although more expensive than
standard telephone wire, it is
much less susceptible to
interference and can carry much
more data. COAXIAL CABLE

16.  Fiber optics is a
particularly popular
technology for local-area
networks. In addition,
telephone companies are
steadily replacing
traditional telephone lines
with fiber optic cables. In
FIBER-OPTIC CABLE
the future, almost all
communications will
employ fiber optics

18.  Microwave communication is
the transmission of signals
via radio using a series of
microwave towers.
Microwave communication is
known as a form of "line of
sight" communication,
because there must be
nothing obstructing the
transmission of data
between these towers for MICROWAVE DATA
signals to be properly sent TRANSMISSION
and received.

19.  Satellite is a specialized wireless
receiver/transmitter that is
launched by a rocket and placed
in orbit around the earth. There
are hundreds of satellites
currently in operation. They are
used for such diverse purposes as
weather forecasting, television
broadcast, amateur
radio communications, Internet
communications, and the Global SATELLITES
Positioning System, (GPS).

21. In telecommunications, data transfer is usually
measured in bits per second. For example, a typical
low-speed connection to the Internet may be
33.6 kilobits per second (Kbps). On Ethernet local
area networks, data transfer can be as fast as
10 megabits per second. Network switches are
planned that will transfer data in the terabit range.

23. Bandwidth describes the maximum data transfer rate
of a network or Internet connection. It measures how
much data can be sent over a specific connection in a
given amount of time.

24. Baseband refers to the original frequency range of a
transmission signal before it is converted, or
modulated, to a different frequency range.

25. refers to high-speed data transmission in which a single cable
can carry a large amount of data at once. The most common
types of Internet broadband connections are cable modems
(which use the same connection as cable TV) and DSL
modems (which use your existing phone line). Because of its
multiple channel capacity, broadband has started to replace
baseband, the single-channel technology originally used in
most computer networks.

26.  The word modem is actually
short for
Modulator/Demodulator. A
modem is a communications
device that can be either internal
or external to your computer. It
allows one computer to connect
another computer and transfer
data over telephone lines. The
original dial-up modems are
becoming obsolete because of
their slow speeds and are being
replaced by the much faster cable INTERNET MODEM
and DSL modems.

27.  An external modem is a box that
attaches to a computer's COM
port via cables.
EXTERNAL
MODEM

28.  A modem that resides on
an expansion board that plugs
into a computer.
INTERNAL MODEM

29.  A device you can attach to
a personal computer that enables
you to transmit and receive
electronic documents as faxes. A
fax modem is like a regular
modem except that it is designed
to transmit documents to a fax
machine or to another fax modem.
Some, but not all, fax modems do
double duty as regular modems. As
with regular modems, fax modems
can be either internal
or external. Internal fax modems FAX MODEM
are often called fax boards.

30. Multiplexer is a device that selects one of
several analog or digital input signals and forwards the
selected input into a single line.

31. A type of multiplexor that combines multiple channels onto a
single transmission medium in such a way that all the
individual channels can be simultaneously active.

32. This processor is a computer that handles communications
processing for a mainframe by connecting to the
communications lines on one end and the mainframe on the
other. It transmits and receives messages, assembles and
disassembles packets, and detects and corrects errors.
Sometimes it is synonymous with a communications
controller, although the latter is usually not as flexible.