Most animals and even some plants have limited powers of communication to signal other members of their species, either for breeding or to sound a warning.
Animal communication may use any of sound, chemicals released into the air or placed on surfaces to be smelled or tasted, visual signals, and touch.
Communication is one of the things that makes us human, and since it allows us to adapt our behaviour, it has played and plays a major role in human evolution.
One definition of modern humans is that they were the first of the great apes which had a complex speech, able to support planning and passing on ideas.
Writing has developed a number of times around the world. Writing may involve symbols that represent sounds or ideas, and both forms have been used.
In history, writing systems have been understood by small numbers of people, unlike the situation this century, where reading and writing are common skills.
In 1799, a dark granodiorite slab, the Rosetta stone, with inscriptions in Greek and Egyptian hieroglyphic and demotic scripts, was found in Egypt, and stolen.
Languages tend to borrow words from each other, and languages change over time. Only the linguistically foolish object to loan words and useful neologisms.
A modem must be used to send digital signals over analog lines by converting the digital signal of a computer to 'sounds' and back again at the other end.
The Internet relies on packet switching, where a signal is converted into packets of information that are sent separately, and reassembled at the other end.
Good communication depends on a high signal-to-noise ratio: noise in this sense can include chatter, spam, advertising and other forms of barbarity.
A lot of international communication is by satellite, but with packet switching, satellites and optic fibre may be seamlessly and invisibly combined.
Light can be 'piped' through optic fibre, which is a transparent solid fibre, designed to keep light running straight down the middle of the fibre.
Fibre optics methods can carry very large amounts of digital information, and do not need a modem, since the actual transmission is digital, light or no light.
Special methods used to add and multiplex signals so they can be sent over the same system, as in the use of several colours on a single optic fibre.
Separate technologies tend to be combined, in a process called convergence, as in the addition of Internet access and digital cameras to mobile phones.
Transmission errors may be reduced by a parity check, which is a quick test to see if a received packet is likely to have suffered degradation along the way.
Parity checks that are used in the transmission of data are imperfect, and in critical and life-threatening situations, need to be double or triple-checked.
No system is ever entirely fail-safe. All we can ever do is make them as safe as we can, by redundancies, cross-checks, and the careful logging of changes.
No system has yet been made that is entirely fool-proof from misuse and tampering, because one determined fool can beat one hundred highly-trained experts.
An automatic telephone exchange was an early form of computer: in a very real sense, the world's telephone systems today make up a giant computer.
The murderer, Dr. Crippen, was captured in 1910 by the use of radio signals, while attempting to escape on the Montrose, demonstrating a loss of isolation.
When the Titanic was holed in 1912, most of the survivors lived thanks to the use of radio signals to send a distress call, demonstrating a loss of isolation.
Radio signals travel on a carrier wave, using one of two forms of modulation: they use either amplitude modulation or frequency modulation of the carrier.
In 1960, the first weather, communications, and navigation satellites were launched. These primitive models were soon replaced by more effective satellites.
This file is http://members.ozemail.com.au/~macinnis/scifun/splatcomms.htm, first created on February 16, 2008. Last recorded revision (well I get lazy and forget sometimes!) was on February 16, 2008.