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The DSLAM at the access provider is the equipment that really allows DSL to happen. While most of the ADSL transceivers sold by ISPs and telephone companies are simply transceivers, the devices used by businesses may combine network routers, network switches or other networking equipment in the same platform. According to equipment manufacturers, most of the ADSL equipment installed today uses DMT. The limit for ADSL service is 18,000 feet (5,460 meters), though for speed and quality of service reasons many ADSL providers place a lower limit on the distances for the service. Monitoring and sorting out the information on the bidirectional channels, and keeping up with the quality of all 247 channels, makes DMT more complex to implement than CAP, but gives it more flexibility on lines of differing quality. Thankfully, it can be revived once it dries out. By limiting the frequencies carried over the lines, the telephone ­system can pack lots of wires into a very small space without worrying about interference between lines. In this article, we explain how a DSL connection manages to squeeze more information through a standard phone line -- and lets you make regular telephone calls even when you're online.

The company that offers DSL will usually provide the modem as part of the installation. When you connect to the Internet, you might connect through a regular modem, through a local-area network connection in your office, through a cable modem or through a digital subscriber line (DSL) connection. CAP and DMT are similar in one way that you can see as a DSL user. DSLAMs are generally flexible and able to support multiple types of DSL in a single central office, and different varieties of protocol and modulation -- both CAP and DMT, for example -- in the same type of DSL. An earlier and more easily implemented standard was the carrierless amplitude/phase (CAP) system, which was used on many of the early installations of ADSL. ADSL is a distance-sensitive technology: As the connection's length increases, the signal quality decreases and the connection speed goes down. Each channel is monitored and, if the quality is too impaired, the signal is shifted to another channel.

The downstream channel (from the server to the user) begins at 240 KHz and goes up to a point that varies depending on a number of conditions (line length, line noise, number of users in a particular telephone company switch) but has a maximum of about 1.5 MHz (megahertz). The upstream channel (from the user back to the server) is carried in a band between 25 and 160 KHz. The DSLAM provides one of the main differences between user service through ADSL and through cable modems. ADSL technology can provide maximum downstream (Internet to customer) speeds of up to 8 megabits per second (Mbps) at a distance of about 6,000 feet (1,820 meters), and upstream speeds of up to 640 kilobits per second (Kbps). In practice, the best speeds widely offered today are 1.5 Mbps downstream, with upstream speeds varying between 64 and 640 Kbps. At the extremes of the distance limits, ADSL customers may see speeds far below the promised maximums, while customers nearer the central office have faster connections and may see extremely high speeds in the future.

This is a popular app for teenagers to log on after school and keep open while doing homework. You can leave your Internet connection open and still use the phone line for voice calls. ­ To understand DSL, you first need to know a couple of things about a normal telephone line -- the kind that telephone professionals goa call girls POTS, for Plain Old Telephone Service. Regardless of what it's called, it's the point where data from the user's computer or network is connected to the DSL line. A DSL internet connection is one of many effective communication tools for keeping employees in touch with the office. Unfortunately, these loading coils are incompatible with ADSL signals, so a voice coil in the loop between your telephone and the telephone company's central office will disqualify you from receiving ADSL. Precisely how much benefit you see from ADSL will greatly depend on how far you are from the central office of the company providing the ADSL service. For information on ADSL rates and availability in the United States, go to Broadband Reports. If you’re a member, you can access additional member only resources and information through the member portal. ADSL isn't the only type of DSL, and it's not the only way to get high-speed Internet access.