Finals: Communication system

In telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment (DTE) usually capable of interconnection and interoperation to form an integrated whole. The components of a communications system serve a common purpose, are technically compatible, use common procedures, respond to controls, and operate in unison. Telecommunications is a method of communication (e.g., for sports broadcasting, mass media, journalism, etc.).

A communications subsystem is a functional unit or operational assembly that is smaller than the larger assembly under consideration. Examples of communications subsystems in the Defense Communications System (DCS) are (a) a satellite link with one Earth terminal in CONUS and one in Europe, (b) the interconnect facilities at each Earth terminal of the satellite link, and (c) an optical fiber cable with its driver and receiver in either of the interconnect facilities. Communication subsystem (b) basically consists of a receiver, frequency translator and a transmitter. It also contains transponders and other transponders in it and communication satellite communication system receives signals from the antenna subsystem.

Examples

An optical communication system is any form of telecommunication that uses light as the transmission medium. Optical communications consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. Fiber-optic communication systems transmit information from one place to another by sending light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information. First developed in the 1970s, fiber-optic communication systems have revolutionized the telecommunications industry and played a major role in the advent of the Information Age. Because of its advantages over electrical transmission, the use of optical fiber has largely replaced copper wire communications in core networks in the developed world.

A radio communication system is composed of several communications subsystems that give exterior communications capablilities.[1][2][3] A radio communication system comprises a transmitting conductor[4] in which electrical oscillations[5][6][7] or currents are produced and which is arranged to cause such currents or oscillations to be propagated through the free space medium from one point to another remote therefrom and a receiving conductor[4] at such distant point adapted to be excited by the oscillations or currents propagated from the transmitter.[8][9][10][11]

Power line communications systems operate by impressing a modulated carrier signal on the wiring system. Different types of powerline communications use different frequency bands, depending on the signal transmission characteristics of the power wiring used. Since the power wiring system was originally intended for transmission of AC power, the power wire circuits have only a limited ability to carry higher frequencies. The propagation problem is a limiting factor for each type of power line communications.

A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. The term duplex is not used when describing communication between more than two parties or devices. Duplex systems are employed in nearly all communications networks, either to allow for a communication "two-way street" between two connected parties or to provide a "reverse path" for the monitoring and remote adjustment of equipment in the field.

A tactical communications system is a communications system that (a) is used within, or in direct support of, tactical forces, (b) is designed to meet the requirements of changing tactical situations and varying environmental conditions, (c) provides securable communications, such as voice, data, and video, among mobile users to facilitate command and control within, and in support of, tactical forces, and (d) usually requires extremely short installation times, usually on the order of hours, in order to meet the requirements of frequent relocation.

NETIQUETTECYBEBERSPACE is where the computer culture often based on the

technological limits of cyberspace-and common courtesy taken from the noncomputer world are mixed to form a special kind of etiquette network etiquette, or netiquette.

**THE CORE RULES of NETIQETTE **NetiquetteRULE1: Remember that the person reading your mail or posting that can

be hurt. Corollary1: It’s not nice to hurt other people's feelings. Corollary2: Never mail or post anything you wouldn't say to your

reader's face. Corollary3: Notify your readers when flaming.

RULE2: Adhere to the same standards of behavior online that you follow

in real life. Corollary1: Be ethical Corollary2: Breaking the law is bad netiquette

RULE3: Know where you in cyberspace. Corollary1: Netiquette varies from domain to domain. Corollary2: Lurk before you leap.

RULE4: Respect other people's time and bandwidth. Corollary1: its okay to think that what you're doing at the moment

is the most important thing in the universe, but don't expect anymore else to agree with you.

Corollary2:Post messages to the appropriate discussion group. Corollary3:Try not to ask stupid questions on discussion groups. Corollary4:Read the FAO(frequently asked questions)document. Corollary5:When appropriate, use private e-mail instead of posting

to the group. Corollary6:Don't post subscribe, unsubscribe, or FAQ requests.

Corollary7:Don't waste expert reader's time by posting basic

Information. Corollary8:If you disagree with the premise of a particular

Discussions group, don’t waste the time and bandwidth of

the members by telling them how stupid they are just stay

away. Corollary9: Conserve bandwidth when you retrieve information from a

host or server.

RULE5:Make yourself look good online. Corollary1: Check grammar and spelling before you post. Corollary2: Know what you're talking about and make sense. Corollary3:Don't post flame-bait.

RULE6: Help keep flame wars under control. Corollary1: Offer answers and help to people who ask questions on

Discussions groups. Corollary2: If you've received e-mail answers to a posted question

Summarize then and post the summary to the discussions

group.

RULE7:Help keep flame-bait under control. Corollary1:Don't respond to flame-bait. Corollary2:Don't post spelling or grammar flames. Corollary3: If you've posted flame-bait or perpetuated a flame

war, apologize.

RULE8:Respect other people's privacy. =Don't read other people's private e-mail.

RULE9:Don't abuse your power. =The more power you have, the more important it is that you use it

well.

RULE10: Be forgiving of other people's mistakes. =You were a network newbie one too!

The Ten Commandments of Computer Ethics

1. Thou shalt not use a computer to harm other people.

2. Thou shalt not interfere with other people's computer work.

3. Thou shalt not snoop (sneak) around in other people's computer files.

4. Thou shalt not use a computer to steal.

5. Thou shalt not use a computer to bear false witness.

6. Thou shalt not copy or use proprietary (licensed) software for which you have not paid.

7. Thou shalt not use other people's computer resources without authorization or proper compensation.

8. Thou shalt not appropriate (criticizing or correcting) other people's intellectual output.

9. Thou shalt think about the social consequences (cost) of the program you are writing or the system you are designing.

10. Thou shalt always use a computer in ways that insure consideration and respect for your fellow human.