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Encyclopedia > DSL modem
Westell Model 6100 ADSL modem
Westell Model 6100 ADSL modem

An asymmetric digital subscriber line transceiver, also known as an ADSL modem or DSL modem, is a device used to connect a single computer to a DSL phone line, in order to use an ADSL service. Some ADSL modems also manage the connection and sharing of the ADSL service with a group of machines: in this case, the unit is termed a DSL router or residential gateway. A DSL modem acts as the ADSL Terminal Unit or ATU-R, as the telephone companies call it. The acronym NTBBA (network termination broad band adapter, network termination broad band access) is also common in various countries. Because a DSL modem is a bridge, it has no interface and the IP address that is configured to the computer it is attached to is assigned to the device. Image File history File links Download high-resolution version (1638x1596, 385 KB)[edit] Summary A picture I took of a Westell Model 6100 ADSL modem/router to replace the low-res, suspected copyvio on the page. ... Image File history File links Download high-resolution version (1638x1596, 385 KB)[edit] Summary A picture I took of a Westell Model 6100 ADSL modem/router to replace the low-res, suspected copyvio on the page. ... The NASA Columbia Supercomputer. ... A DSL Modem DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. ... Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ... A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Linksys befsr41 DSL Router DSL Routers are a type of router that connect a LAN to the Internet via a DSL connection. ... A residential gateway is a hardware device connecting a home network with a wide area network (WAN) or the Internet. ...

Contents

Compared to voiceband modem

The two devices serve fundamentally the same purpose, but differ in important ways. A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ...

  • DSL modems are rarely internal to the computer but instead are wired to the computer's Ethernet port, or occasionally its USB port, while voiceband modems are usually built inside the computer.
  • MS Windows and other operating systems do not recognize DSL modems, hence have no Property Sheet or other internal method to configure them. This is because the transceiver and computer are considered separate nodes in the LAN, rather than the transceiver being a device controlled by the computer (such as webcams, mice, keyboards etc.). Routers can be configured manually, for example using a Web page provided by the modem via the ethernet the router is connected to. DSL modems rarely need to be configured, because they are part of the physical layer of computer networks. They are only forwarding ones and zeros from one medium (CAT5) to another one (telephone line).
  • DSL modems use frequencies from 25 kHz to above 1MHz (see Asymmetric Digital Subscriber Line), in order not to interfere with voice service which is primarily 0-4 kHz. Voiceband modems use the same frequency spectrum as ordinary telephones, and will interfere with voice service.
  • DSL modems vary in data speed from hundreds of Kilobits per second to many Megabits, while voiceband modems are limited to approximately 50 kbit/s.
  • DSL modems exchange data with only the DSLAM to which they are wired, which in turn connects them to the Internet, while most voiceband modems can dial directly anywhere in the world.
  • DSL modems are intended for particular protocols and sometimes won't work on another line even from the same company, while most voiceband modems use international standards and can "fall back" to find a standard that will work.
Inside component (chip) of a typical ADSL modem.

Most of these differences are of little interest to consumers, except the greater speed of DSL and the ability to use the telephone even when the computer is online. Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ... Note: USB may also mean upper sideband in radio. ... It has been suggested that Maintenance OS be merged into this article or section. ... A screenshot of a web page. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ... This article does not cite any references or sources. ... “Computer Networks” redirects here. ... Cat5 patch cable Category 5 cable, commonly known as Cat 5, is a twisted pair cable type designed for high signal integrity. ... A telephone line (or just line) is a single-user circuit on a telephone communications system. ... Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ... In electronics, voiceband means the typical human hearing frequency range that is from 20Hz to 20KHz. ... A digital subscriber line access multiplexer, (DSLAM) is a multiplexer located in the telephone company exchange that provides consumers access to DSL services over twisted pair copper cabling. ... Image File history File links Metadata No higher resolution available. ... Image File history File links Metadata No higher resolution available. ...


Because a single phone line commonly carries DSL and voice, filters are used to separate the two uses. (See DSL filter) A DSL filter is an analog low-pass filter installed on telephones and other analog devices to prevent interference between such devices and Digital Subscriber Line service operating on the same line. ...


Hardware components

As technology advances, functions that are provided by multiple chips can be integrated onto one chip. Higher levels of integration have benefited DSL just as they benefited other computer hardware. A DSL modem requires the following for its operation; exactly what is on the circuit card and how it is arranged can change as technology improves:

Figure 1:Three-phase pole-mounted step-down transformer. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ... For other uses, see Data (disambiguation). ... An analog or analogue signal is an allergy continuous in both time and amplitude. ... It has been suggested that this article or section be merged with embedded microprocessor. ... Television signal splitter consisting of a hi-pass and a low-pass filter. ...

Service Features

Apart from connecting to an ADSL service, many modems offer additional integrated features:

Many ADSL modems can have their firmware upgraded to support additional features or fix existing problems. This can be done over the network, or using a dedicated serial connection. This article needs to be wikified. ... TU G.992. ... It has been suggested that Routing protocol be merged into this article or section. ... In Computer Networking, the process of Network Address Translation (NAT, also known as Network Masquerading, Native Address Translation or IP Masquerading) involves re-writing the source and/or destination addresses of IP packets as they pass through a Router or firewall. ... IEEE 802. ... IEEE 802. ... Planet WAP-4000 Wireless Access Point In computer networking, a wireless access (WAP or AP) is a device that connects wireless communication devices together to form a wireless network. ... A network switch is a computer networking device that connects network segments. ... A Virtual Private Network, or VPN, is a private communications network usually used within a company, or by several different companies or organizations, communicating over a public network. ... (DHCP) is a set of rules used by a communications device such as a computer, router or network adapter to allow the device to request and obtain an IP address from a server which has a list of addresses available for assignment. ... Dynamic DNS is a system which allows the domain name data held in a name server to be updated in real time. ... IP Telephony, also called Internet telephony, is the technology that makes it possible to have a telephone conversation over the Internet or a dedicated Internet Protocol (IP) network instead of dedicated voice transmission lines. ... The abbreviation QOS could refer to one of several things: Quality of service, a measure of the reliability of a computer network Queen of the South F.C., a Scottish football club Quarterdeck Office Systems, a software company that is now part of Symantec This is a disambiguation page &#8212... In computing, firmware is software that is embedded in a hardware device. ...


Manufacturers

Currently, Taiwan manufactures most of the ADSL modems in the world, ODM plays a large role with designs from various parts of the world. Below lists an array of designers.

3Com (NASDAQ: COMS) is a manufacturer best known for its computer network infrastructure products. ... Alcatel SA is a global company, headquartered in France that provides hardware, software and services to telecommunications service providers and enterprises. ... Arteriovenous malformation - a congenital disorder of the veins and arteries that make up the vascular system Vision Macau (Associação Visão de Macau) - a political party in Macao AVM GmbH - a German producer of electronic devices Air Vice Marshal - A rank in the United Kingdom and many Commonwealth air... Aztech is a company which designs and manufactures voice and data communications products. ... Belkin International, Inc. ... Billion is a homosexual clothes manufacturer. ... D-Link Corporation is a Taiwanese company that manufactures wireless and Ethernet computer networking products for both consumer and SOHO users. ... Draytek are Manufacturers of a range of ISDN routers, terminal adaptors and PBXs and routers for broadband, cable and ADSL technology. ... Siemens AG (FWB: SIE, NYSE: SI) is the worlds largest electronics company. ... Siemens AG (ISIN: DE0007236101, FWB: SIE, NYSE: SI) is one of the worlds largest companies and Europes largest engineering firm. ... For the district in Saga, Japan, see Fujitsu, Saga. ... Huawei Technologies Co. ... Intertex was founded in 1982 by Karl-Erik Ståhl. ... NETGEAR, founded in 1996, is a manufacturer of computer networking equipment and other computer hardware. ... Netopia is a company, headquartered in Emeryville, California, that produces a variety of broadband products including modems, routers, gateways, and Wi-Fi devices. ... SAGEM (Société d’Applications Générales de l’Electricité et de la Mécanique) was a major French company involved in defence electronics, consumer electronics and communication systems. ... Siemens has the following uses: Siemens is a German family name carried by generations of the telecommunications industrialists, including Werner von Siemens, Sir William Siemens, Wilhelm von Siemens and Peter von Siemens Siemens AG is a German electrical and telecommunications company, founded as a telegraph equipment manufacturer by Werner von... This article is about the media and entertainment company. ... U.S. Robotics (popularly referred to by its acronym USR) is a company that makes computer modems and related technologies. ... Westell Technologies, Inc. ... ZTE Corporation (Chinese: 中兴通讯)(Zhong Xing Telecommunication Equipment Company Limited) SEHK: 0763, a state-owned corporation launched in 1985, is one of the largest telecommunications (GSM, 3G, WCDMA, CDMA, SDH, ADSL, IPTV, PSTN) manufacturers and wireless solutions providers in the Peoples Republic of China. ... ZyXEL Prestige 600 series modem. ... Zoom Technologies, Inc. ...

External links

  • Understanding the lights on your ADSL modem/router

  Results from FactBites:
 
Howstuffworks "How DSL Works" (567 words)
DSL is a very high-speed connection that uses the same wires as a regular telephone line.
DSL doesn't necessarily require new wiring; it can use the phone line you already have.
DSL exploits this "extra capacity" to carry information on the wire without disturbing the line's ability to carry conversations.
Digital Subscriber Line - Wikipedia, the free encyclopedia (1356 words)
DSL is the principal competition of cable modems for providing high speed Internet access to home consumers in Europe and North America.
DSL takes advantage of this unused bandwidth of the local loop by creating 4312.5 Hz wide channels starting between 10 and 100 kHz, depending on how the system is configured.
Like analog modems, DSL transceivers constantly monitor the quality of each channel and will add or remove them from service depending on whether or not they are usable.
  More results at FactBites »

 
 

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