Copy of the original phone of Alexander Graham Bell at the Musée des Arts et Métiers in ParisA replica of one of Chappe's semaphore towers.Digital television standards and their adoption worldwide.
Find exactly what you want now for networking - routers, switches, hubs, cables, UPS, APC, workstation components, memory, servers, security, storage equipments.

Telephone Systems, Telecom

Telecommunication is the transmission of signals over a distance for the purpose of communication. more...

Home
Cables, Connectors
Filers, Load Balancers
Home Networking, Cable & DSL
Hubs
KVM Switch Boxes, Cables
Mainframe, DEC, VAX, AS/400
Network Interface Cards,...
Networking, Telecom Tools
Other Networking Equipment
Print Servers, Wired
Racks, Mounts & Patch Panels
Router Components, Memory
Routers, Wired
Security, Firewall, VPN
Server Components, Memory
Servers
Software
Software, Operating Systems
Storage Equipment, NAS, SAN
Switch Components, Memory
Switches
Telephone Systems, Telecom
Concentrators, Terminal...
Conference Equipment
Converters
CSU, DSU, SMDSU
Fax Boards, Fax Modems
Modems, Modem Boards
Multiplexers
Music On Hold, MOH
Other
Parts, Components
Remote Access Devices
Skype Devices
Telephone Sets, Handsets
Telephone Systems, PBX
Voicemail, Voice Processing
VOIP, Internet Telephony
UPS, Power Protection, APC
Wholesale Lots
Wireless Networking, WiFi
Workstation Components,...
Workstations, Terminals

In modern times, this process almost always involves the sending of electromagnetic waves by electronic transmitters but in earlier years it may have involved the use of smoke signals, drums or semaphore. Today, telecommunication is widespread and devices that assist the process, such as the television, radio and telephone, are common in many parts of the world. There is also a vast array of networks that connect these devices, including computer networks, public telephone networks, radio networks and television networks. Computer communication across the Internet, such as e-mail and instant messaging, is just one of many examples of telecommunication.

Telecommunication systems are generally designed by telecommunication engineers. Major contributors to the field of telecommunications include Alexander Bell who invented the telephone (as we know it), John Logie Baird who invented the mechanical television and Guglielmo Marconi who first demonstrated transatlantic radio communication. In recent times, optical fibre has radically improved the bandwidth available for intercontinental communication, helping to facilitate a faster and richer Internet experience. And, digital television has eliminated effects such as snowy pictures and ghosting. Telecommunication remains an important part of the world economy and the telecommunication industry's revenue has been placed at just under 3% of the gross world product.

Key concepts

The basic elements of a telecommunication system are:

a transmitter that takes information and converts it to a signal for transmission; a transmission medium over which the signal is transmitted; a receiver that receives and converts the signal back into usable information;

For example, consider a radio broadcast. In this case the broadcast tower is the transmitter, the radio is the receiver and the transmission medium is free space. Often telecommunication systems are two-way and devices act as both a transmitter and receiver or transceiver. For example, a mobile phone is a transceiver. Telecommunication over a phone line is called point-to-point communication because it is between one transmitter and one receiver, telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous receivers.

Signals can either be analogue or digital. In an analogue signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values (e.g. 1's and 0's). Telecommunications devices convert different types of information, such as sound and video, into electrical or optical signals. Electrical signals typically travel along a medium such as copper wire or are carried over the air as radio waves. Optical signals typically travel along a medium such as strands of glass fibers. When a signal reaches its destination, the device on the receiving end converts the signal back into an understandable message, such as sound over a telephone, moving images on a television, or words and pictures on a computer screen.

Read more at Wikipedia.org


[List your site here Free!]

*New* Nortel Norstar T7316E, T7316 E Telephone Phone $112.99 *New* Avaya Partner Acs 7.0 R7 Phone System w/10x 18D's $2,499.00
*New* Nortel Norstar Cics Phone System 4x16, 5-Phones! $1,049.95 New! Avaya/Lucent Partner Acs 7.0 / R7 Processor - Sale $505.00
*New* Nortel Norstar Mics 8x32 Phone System w/10-T7316E $2,999.00 Shoretel Shoreline Polycom Soundpoint Ip 530 Phone $19.99
Sprint Protege Ati Trunk Card $159.99 Panasonic Kx-T2135 Easa-Phone Handset Cords Guaranteed $14.99
Linksys Network Optimizer Gaming VoIp Model Ogv200 New $36.99 Panasonic Va-20840 Easa-Phone Extension Expansion Guara $39.99
Nortel Northern Telecom Meridian M7208 Nt8B31Ac-03 Nib! $59.98 Complete Merlin Legend Communications system, 54 phones $599.99
PolyCom Voice Station (conference phone) $100.00 X400M Fxo Module $50.00
Sprint Protege Phone System - Server & 29 Phones $595.00 Brand New 3Com Nbx 100 Voip Ip Phone System W/Module $999.99
Nec Electra Elite 48 8 Phone System Great Condition! $150.00 At&T Mls-18D Bu3151 Partner avaya Att Lucent Guaranteed $59.99
Samsung 24 Button Lcd Phone 24B keyset Dcs 24 B Display $99.00 Samsung Lcd 12B Keyset Dcs 12 Button Display Black $79.00
Rca Conference Phone 25001Re2-A $70.00 Pelco Simlex Color Multiplexer Mx4016Cs $799.99
*New* Nortel Call Pilot CallPilot 150 w/ 32 Mb - Rel 3 $1,549.00 *New* Nortel Meridian M3904 Phone - Rel 3 - 3904 !!! $165.00
New Nortel Bcm 400 4.0 T1x32 VoIp Business Phone System $9,899.95 *New* Avaya Partner Acs R6 Phone System w/5x 18D Phones $1,375.00
*New* Avaya Ip Office Ip406 Phone System w/ 5410 + 5420 $2,995.00 Nortel Meridian Caller Id LineCard Nt5B41Ga-93 Set of 3 $299.00
Avaya Ip Office 500 Ip500 Phone System 8x16 w/5410+5420 $3,995.00 *New* Cisco Cp-7940G Ip Phone - Global Spare 7940G 7940 $189.95
*New* Nortel Norstar T7208 Charcoal Phone Nt8B26 $95.00 *New* Aastra 57i Ip Phone 480i 55i 53i 9133i 9112i $212.95
Linksys Adsl Wall Mount Filter $3.99 New Logitech 980440-1403 Quickcall Usb Speakerphone $84.49
Nortel Meridian 1/Sl1 Console M2250 Operator Attendant $124.95 Avaya Transtalk 9031Dcp/Dz Wireless Phone 7815H09A $19.99
At&T Paradyne 3151-B3-010 T1/Csu/Dsu $25.00 SkypeKey Pc Mac Usb Pstn Rj11 phone adapter Skype Yahoo $20.00
Lot of 10 At&T Lucent 7303 Merlin 10 Button Phone Black $124.95 Usb Wireless Certified Skype Cordless Voip Phone Pc Us $44.99
2 Polycom Avaya 4690 Ip Conference Stations $150.00 Sony Evi-D30 Intelligent Communication Color Camera $199.00
Cisco 7921G Phone Standard Battery, Cp-Batt-7921G-Std $56.95 Cisco 7920 Wireless Voip Phone and Battery Bundle $249.95
Cisco 79Xx Series Locking Wall Mount Kit, Cp-Lckngwallm $24.95 Lot of 2 Nortel Networks T7316E Speakerphone w/ Display $19.95
Rad Vmux-110 Tdm Ip DrivenVoiceTrunk-Vmux-110 /Ac/T1/24/ $9.99 Avaya Tn2400 Net/Pkt Bp Conn Tn2401 Netcon/{ Intfc V3 $49.95
Lot of 4 Lucent Mlx-16 Dp Telephone Sets Merlin Legend $60.00 5 Toshiba Dkt-2010-S Dkt-2010S Dkt2010S Charcoal ref $225.00
5 Avaya Definity 6424D+ Phone Grey Refurbish $375.00 Toshiba Ekt 6510-H Telephone $30.00
Sangoma A104 Quad T1/E1/J1 Pci Card $900.00 6 pcs New Nortel Poe Ip Phone 1110 Ntys02Bae6 Graphite $780.00
Mt-16H Macrotel Hybrid Phone System $24.99 4 pcs Nortel M7310 + 1 pc M7324 Phone, Black, Refurbish $350.00
Lot of 6 Lucent Merlin Legend Mlx-10 Dp Telephones $40.00 Compact Usb Micro 2 Port Kvm Switch Full Set Kit New $35.64
Merlin Avaya Pbx With 8 Lines , 10 Phones $400.00 New Dual Cordless Phone Landline+Skype Voip by Linksys $26.74
At&T Merlin 410 Control Unit & Cartridge Type Ii. $10.00 Brand New Motorola Vonage Router phone adapter Vt2142 $29.99
Usb 2.4G 2.4Ghz Wireless Skype VoIp Phone Handset Eh $28.89 Avaya Magic on Hold/with power supply $24.95
New Mini Rdr Wedge Track 1 2 & 3 White $57.24 New Magnetic Card Reader Wedge Track 2 Black $53.24
New Grandstream HandyTone Ht-486 VoIp router Spa2102-Na $44.43 Polycom ViewStation Pvs-14Xx Ntsc Uisc Interface $349.99
Nec Xen Ipk Telephone System w/ 5x Nec Dtr-16D Handsets $1,204.25 Netcomm V20 Dect Cordless Phone Kit + VoIp & Pstn Calls $19.22
New Polycom Cx700 Ip Phone $476.99 New Vsx Ceiling Microphone Array With 2Drop Cable... $812.99
New Targus Wireless Optical Mouse for Apple $45.24 New Wasp Wlr8905 Handheld Bar Code Reader $185.99
New Polycom SoundStation2W Conference Phone $429.99 New Microsoft Wireless Optical Mouse $39.95
New Polycom Microphone Cable $28.24 New Total Access 924E W/ Vpn Card Cpnt $2,428.99
Gentner Ti7200 Teleconferencing Interface $9.99 New D-Link Dph-540 Wi-Fi Phone $214.99
New Adesso CyberPad Digital Notepad $146.99 Three (3) 3Com 1102 Nbx Ip Voip Phones $99.00
Lot of 3 Lucent Merlin Mlx 20-L Telephones and 2 Dss $60.00 At&T 945 4-Line Corded Business System Speaker Phone $66.00
At&T Paradyne Acculink Access Controller 2525, Nr $49.00 Cisco 7961 New In Boxes $900.00
Dictaphone Dictation Hand Microphone 862300 $9.99 Dialogic D 240Sc-T1 Voice Interface Card Rev3 $99.99
Panasonic Dbs Vb 43220 22 Key Digital Phone $4.99 Vodavi 8 button phone 3012-71 ( black) $30.00
Partner Euro 18 Telephone At&T Lucent Avaya Nice Phone $29.95 Panasonic Kx-T7441 Dss Console $30.00
Brooktrout Vantage Pci/8L Plug-In Card Voice Interface $99.99 VoIp Skype Stereo Pc Headset Headphone w/Mic Microphone $9.95
Avaya Partner 18D Display Phone Lucent At&T Euro Att $64.95 Digium Te110P T1 Card $200.00
Voip Usb 2.0 Internet/Ip Phone For Skype Msn/Caller Id $4.38 Digium Tdm11B Analog Card $150.00
Office Phone System - Nec Dx7Na-48 Model $879.00 Usb Internet Voip Skype Adapter to Cordless Home Phone $9.99
Click to see more Telephone Systems, Telecom items
Prices current as of last update, 07/03/08 3:31pm.


See also...
Concentrators, Terminal Access, Telephone Systems, Telecom
Conference Equipment, Telephone Systems, Telecom
Converters, Telephone Systems, Telecom
CSU, DSU, SMDSU, Telephone Systems, Telecom
Fax Boards, Fax Modems, Telephone Systems, Telecom
Modems, Modem Boards, Telephone Systems, Telecom
Multiplexers, Telephone Systems, Telecom
Music On Hold, MOH, Telephone Systems, Telecom
Other, Telephone Systems, Telecom
Parts, Components, Telephone Systems, Telecom
Remote Access Devices, Telephone Systems, Telecom
Skype Devices, Telephone Systems, Telecom
Telephone Sets, Handsets, Telephone Systems, Telecom
Telephone Systems, PBX, Telephone Systems, Telecom
Voicemail, Voice Processing, Telephone Systems, Telecom
VOIP, Internet Telephony, Telephone Systems, Telecom

Home Contact Resources Exchange Links eBay