How do DSL Modems Operate

When trying to decide what kind of modem to buy, it can be helpful to understand. How do DSL Modems Operate or how they all work. The purpose of a modem is to connect computers or networks to the internet, but this is done slightly differently with different modems.

A DSL modem creates an internet connection through copper telephone lines, but there are different types of DSL, and each one operates slightly differently as well. ADSL (asymmetric digital subscriber line) modems are the most common form of DSL. The “asymmetric” aspect refers to the fact that information flows faster from the internet to the user than it does from the user back to the internet.

What is DMT

Most ADSL modems today operate using a DMT (discrete multitone) system. This separates signals from the telephone line into 247 different channels. In a very basic sense, each channel acts as a connection between the user and the internet.

If there is interference on a channel, then the modem will just switch to another channel, allowing clearer transmission and reception.

The channels at the lower end of the line can be bidirectional, which means that they take information from the server to the user and from the user back to the server. The rest of the channels are one-way.

Most DSL modems (not just ADSL ones), will have a small filter attached to them. This blocks all signals that are above a certain level (4KHz). All voice calls are transmitted below 4KHz), so the rest of the signals are blocked, to avoid interference.

This is the difference between DSL and dial-up internet – with the latter, you couldn’t take calls and use the internet, because of interference. The filter prevents this issue and allows you to take calls while simultaneously surfing the net.

What is DSLAM

The ADSL modem you possess is actually a transceiver, which is connected to a receiver on the phone company’s end. This is where your computer connects directly to the DSL line and receives data from the phone/internet company.

The receiver at the phone company (also known as a DSLAM, or digital subscriber line access multiplexer) is capable of handling numerous transceivers, without overloading the access port to the internet.

This means that no matter how many DSL modem users are trying to use the internet at a given time, there is no way that this will affect the speed of the internet. Inevitably, there are still some situations that can cause the internet to be slow on a DSL modem, but an increasing number of simultaneous users is not a factor.

Downsides to DSL modems and internet speed

Understanding how a DSL modem operates can help you to understand. If it is the right option for you, and also help you to understand its shortcomings. Because DSL modems use copper telephone wires to transfer signals, they are susceptible to any problems with these wires.

The copper wires work as excellent conductors, but the further your home is from a telephone exchange, the slower your internet is likely to be. You cannot alter this fact, so it’s worth finding out the distance in your specific situation, to see if your location prohibits you from making the most of DSL internet.


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