|Samuel F. B. Morse conceived of
his version of an electromagnetic telegraph in 1832 and constructed an
experimental version in 1835. He did not construct a truly practical system
until 1844, when he built a line that carried electronic pulses from Baltimore to Washington, D.C.
a local area network (LAN).
Morse's invention transformed communications almost overnight. Within ten years after the first telegraph line opened, 23,000 miles of wire crisscrossed the country in a wide area network (WAN). The development of the telegraph had a significant impact on the development of the West, made railroad travel safer, and allowed businessmen to conduct their operations more quickly and profitably. Very few inventions have had such an immediate and long-lasting impact.
the first line was set up, do to the technology at the time(1844) Mores was only
able to send a electronic signal down the telegraph line approximately 30 miles(
the distance that an electronic signal will travel down a wire until the pulse
is no longer readable (attenuated) is called segment length.
|Telegraph Key/Transmitter ----->>||Segment Length Approximately 30 Miles------>>||Receiver Telegraph|
To go any further required another transmitter and receiver. A telegraph operator would receive the message turn around and key in on another transmitter down the other line the message that was to be sent. He repeated the message on the next circuit in line. In the early telegraph operators function as repeaters of the information to send the message down the next link in the network.
After a few months the telegraphic operator not only functioned as a repeater of the message but he also had to chose which (circuit) line (route) the message was to be sent on.
|Which Route to take?||Operator||Transmit||Receive- Albany|
The telegraph message in its header now had to say who it was going to and which route they could be found on. The telegraph operator now functions as a repeater and a router. As the telegraph reach the borders of the United States (Canada and Mexico) the telegraph operator not only had to repeat and route the message he had to be able to use the other countries hardware and translate the message from one language to another (protocol). Thus, the telegraph operator functioned as a gateway.
By 1861 the telegraph crossed the United States in a national network privately owned Intranet. The US was the first country to have trans continental electronic communication. Prior to 1861 a message sent from NY to SF could take anywhere from two months to seven months. With the telegraph a message could be sent in a matter of minutes. The civil war began also in 1861, at which time the telegraph was taken over by the federal government until the end of the war. Since the telegraph was now publicly owned it became an Internet for the duration of the war. Immediately a group of union soldiers were assigned the task of changing their electronic signals into code (encryption) and then decoding the message (decryption). Additionally they had to determine which messages were false (virus) that had been sent by the rebels. This group referred to them selves as the firewall brigade and functions to prevent unauthorized access and false messages being sent on the union telegraph. They functioned as a firewall.
One of the limitations of the early telegraph was the speed at
which a telegraph operator could key the message and the speed a which the
receiving operator could understand the message (bottle neck).
That is if the transmitting operator could key at 25 words a minute (frequency
per minute) and the receiving operator could only understand 20 words a minute
then the bandwidth of the closed circuit between the two would be only 20
words per minute. Thus the slowest operator on the network of circuits
determines the fastest speed at which information can be transmitted across the
network. At the beginning of the electronic telecommunications industry the only
transmission device used was copper wire.
In 1890 Marconi developed the first electro magnetic wireless transmitter. By 1920 the first voice transmission was achieved. In the early thirties coaxial cable was developed and was used for electronic communication. In the sixties the military began using satellites to send signals by transmitting up to the satellite from a ground station (uplink) and then transmitting from the satellite to ground stations (downlink). In the early eighties fiber optic cable was developed which used light particles (photons) instead of electrons for data transmission. Today copper wire in the form of twisted pair and and coaxial are used for electron transmission at a speed of 80,000 miles per second, fiber optic is used for photon transmission at 186,000 miles per second, and electromagnetic wireless methods of data transmission at 186,000 miles per second are used in our world wide internet (publicly owned). Twisted pair cable has the lowest bandwidth and segment length (about 300 ft). Coaxial cable bandwidth is higher but the segment length is about the same. Fiber Optic cable band with is much higher and the segment length is 1000 miles. Wireless bandwidth is unlimited and segment length is limited by the transmitters power and the receivers power.
In summary today computers have taken over the functions of human operators and operate as repeaters, routers, gateways and firewalls using twisted pair and coaxial wire for electron transmission of data, fiber optic for photon transmission of data, and wireless for magnetic pulse transmission of data over LAN, WAN, Intranet (privately owned) and Internet (publicly owned). Attenuation refers to the loss of signal in a circuit and segment length refers to the distance a signal will travel before attenuation occurs. Bandwidth refers to how much data can be transmitted at once using electronic, photonic or magnetic pulse. In the computer world bandwidth equals the highest frequency minus the lowest frequency that a conductor will support. Frequency is measured in hertz. 1 hertz equals one cycle per second. In the computer world, when you have a CPU speed of 1 giga hertz the speed is a 1000 million cycles per second.
In the future micro laser tunneling technology will improve security and experimentation with particle transmission that is faster than the speed of light will improve bandwidth and speed.