Printer Friendly
The Free Dictionary
1,087,855,465 visitors served.
?
Dictionary/
thesaurus
Medical
dictionary
Legal
dictionary
Financial
dictionary
Acronyms
 
Idioms
Encyclopedia
Wikipedia
encyclopedia
?

communications

   Also found in: Dictionary/thesaurus, Acronyms, Wikipedia, Hutchinson 0.07 sec.

In the electronic world, it is the transfer of data and information from one location to another. "Data communications" or "datacom" refers to digital transmission. "Telecommunications" or "telecom" refers to voice or a mix of voice and data, both analog and digital. Although all long distance trunks are digital, and digital lines get closer to the end user all the time, there is still analog service into homes and offices.

"Networking" refers specifically to a local area network (LAN); however, a wide area network (WAN) is commonly called a telecom network.

The term "communications" may refer only to telecom-related subjects such as PBXs, modems, call centers and the like. However, the word is also a common English word such as in the "Analog Vs. Digital Communications" headline below. Thus, "communications" is used specifically in some cases and generically in others.

The Protocol
The way data communications systems "talk to" each other is defined in a set of standards called "protocols." Protocols work in a hierarchy starting at the top with the user's program and ending at the bottom with the plugs, sockets and electrical signals. See communications protocol and OSI.

Analog Vs. Digital Communications
Prior to the Internet, the world's largest communications system was the telephone network, a mix of analog and digital communications. The system, which used to be entirely analog transmitting only voice frequencies, is now almost entirely digital. The only analog part is the line between your telephone and a digital conversion point (digital loop carrier) within a mile or so of your house. Analog systems are error prone, because the electronic frequencies get mixed together with unwanted signals (noise) that are nearby.

Amplifiers Boost the Noise
In analog telephone networks, amplifiers were placed in the line every few miles to boost the signal, but they could not distinguish between signal and noise. Thus, the noise was amplified along with the signal. By the time the receiving person or machine got the signal, it may have been impossible to decipher.

Repeaters Regenerate
In a "digital" network, only two (binary) distinct frequencies or voltages are transmitted. Instead of amplifiers, repeaters are used, which analyze the incoming signal and regenerate a new outgoing signal. Any noise on the line is filtered out at the next repeater. When data are made up of only two signals (0 and 1), they can be more easily distinguished from the garble. Digital is simple.

The First Analog Communications
In 1876, Alexander Graham Bell sent the first electronic communications over a wire when he said, "Mr. Watson. Come here! I want you!" (Image courtesy of AT&T.)



How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
?Page tools
Printer friendly
Cite / link
Email
Feedback
? Mentioned in ? References in classic literature
 
Once or twice lately I have had it reported to me that communications from the other side to Mr.
Their hunters and advanced troops held the first communications with the savage occupants, and the earliest written accounts we possess of these vast regions, are from the pens of their missionaries.
Oliver, quite elated and honoured by a sense of his importance, faithfully promised to be secret and explicit in his communications.
 
Encyclopedia browser? ? Full browser
 
Communication Workers' Union (UK)
Communication Zone Rear (Combat Military Zones)
Communication Zone West
Communication(s)
Communication(s) Handling Facilities
Communication, Assessment, and Prioritization Program
Communication, Command, and Control
Communication, Computing and Technology in Education
Communication, Culture & Technology
Communication, Culture & Technology
Communication, Culture & Technology (CCT)
Communication, Culture & Technology (CCT)
Communication, Electronics, and Navigation
Communication, Link, Information & Entertainment (Sony PDA)
Communication, Transport and General Workers Union
Communication-based train control
Communication-Electronic-Meteorological
Communication/Computer Vulnerability Program
Communication/Rendezvous (Plan, DOD Flight Information Publication)
communicational
communicational
communicational
communicational
communicational
communications
Communications & Computing Infrastructure
Communications & Entertainment Inc. (Atlanta, GA)
Communications & Information Systems
Communications & Information Technology Association (UK)
Communications & Jamming
Communications & Liaison (Internal Revenue Service division)
Communications & Power Industries
Communications & Power Industries International
Communications & Systems Management
Communications & Tracking Simulator
Communications (jazz album)
Communications / Network Riser
Communications Abstracts (magazine)
Communications Access (line)
Communications Access for Everyone
Communications Access Method Identification
Communications Access Processor
Communications Access Protocol
Communications Access Unit
Communications Accounting System (Highland Lakes)
Communications Act
Communications Act
Communications Act 2003
Communications Act of 1934
 
Encyclopedia
?

Disclaimer | Privacy policy | Feedback | Copyright © 2008 Farlex, Inc.
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.. Terms of Use.