ADSL modem or DSL modem is a device used to connect a single computer or router to a DSL phone line, in order to use an ADSL service. Like other modems it is a type of transceiver. It is also called a DSL Transceiver or ATU-R. The acronym NTBBA (network termination broad band adapter, network termination broad band access) is also common in some countries.
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. DSL routers have a functional block which performs framing, while other functional blocks perform Asynchronous Transfer Mode Segmentation and Reassembly, IEEE 802.1D bridging and/or IP routing. Typical user interfaces are Ethernet and USB. Although an ADSL modem working as a bridge does not need an IP address, it may have one assigned for management purposes.
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:
- Power supply: Transformer and capacitor
- Data connection and power circuitry (for example, USB, Ethernet, PCI)
- DSL digital data pump
- DSL analog chip and line driver
- Micro controller
- Filter
Below lists manufacturers an array of designers :
- 2Wire (United States)
- 3Com (United States)
- A-Link (Finland)
- Actiontec (United States)
- Airties (Turkey)
- Alcatel-Lucent (France)
- Allied Telesis (Japan)
- Amplebit (India)
- AVM (Germany)
- Aztech (Singapore)
- Belkin (United States)
- Billion (Taiwan)
- Comtrend (Taiwan)
- D-Link (Taiwan)
- Draytek (Taiwan)
- Efficient Networks (Germany, related to Siemens)
- Fujitsu (Japan)
- Huwei (China)
- Intertex (Sweden)
- Linksys (United States)
- NEC (Japan)
- NetComm (Australia)
- LevelOne (Germany)
- Netgear (United States)
- Netopia (United States)
- Nokia (Finland)
- OvisLink (United States)
- Paradyne (United States)
- RealTime Systems (India)
- Sagem (France)
- Siemens (Germany-United States)
- Symphony
- Telewell (Finland)
- Thomson (France)
- UT Starcom (India)
- U.S. Robotics (United States)
- Westell (United States)
- XaviTech (Taiwan)
- ZTE (China)
- ZyXEL (Taiwan)
- Zoom Technologies (United States)