Post on 02-Jun-2018
transcript
8/10/2019 Morse Telegraphs
http://slidepdf.com/reader/full/morse-telegraphs 1/5
Morse telegraphs (1838 AD)
In the United States, the telegraph was developed by Samuel Morse
and Alfred Vail. Samuel F. B. Morse independently developed an
electrical telegraph in 1836, an alternative design that was capable of
transmitting over long distances using poor quality wire. His assistant,
Alfred Vail developed the Morse code signaling alphabet with Morse.
This was a practical electrical telegraph system, and subsequently
electrical telegraph came to refer to a signaling telegram - a system
where an operator makes and breaks an electrical contact with a
telegraph key, which results in an audible signal at the other end
produced by a telegraph sounder, which is interpreted and transcribed
by a human.
8/10/2019 Morse Telegraphs
http://slidepdf.com/reader/full/morse-telegraphs 2/5
Telephone (1876)
The telephone , often colloquially referred to as a phone, is a
telecommunications device that transmits and receives sound, most
commonly the human voice. Telephones are a point-to-pointcommunication system whose most basic function is to allow two
people separated by large distances to talk to each other. It is one of
the most common appliances in the developed world, and has long
been considered indispensable to businesses, households and
governments.
A landline telephone is connected by a pair of wires to the telephone network,
while a mobile phone or cell phone is portable and communicates with the
telephone network by radio. A cordless telephone has a portable handset which
communicates by radio with a base station connected by wire to the telephone
network, and can only be used within a limited range of the base station.
8/10/2019 Morse Telegraphs
http://slidepdf.com/reader/full/morse-telegraphs 3/5
Radio (1896)
Radio is the transmission of signals by modulation of electromagnetic
waves with frequencies below those of visible light. Radio became
more useful after the invention of electronic devices such as thevacuum tube and later the transistor, which made it possible to amplify
weak signals. Today radio systems are used for applications from
walkie-talkie children's toys to the control of space vehicles, as well as
for broadcasting, and many other applications.
8/10/2019 Morse Telegraphs
http://slidepdf.com/reader/full/morse-telegraphs 4/5
Television (1927)
Television (TV) is a telecommunication medium for transmitting and
receiving moving images that can be monochromatic (shades of grey)
or multicolored. Images are usually accompanied by sound.