Difference Between ADSL and ADSL2 (With Table)

Staying connected to the internet has become almost similar to basic needs today. This brings us to getting an internet connection that guarantees a consistent and secure data rate. Broadband is one of the best ways in this regard. One of the most commonly used broadband technology is the ADSL or Asymmetric Digital Subscriber Line.


The difference between ADSL and ADSL2 is that ADSL2 is an upgraded version having a higher maximum speed, i.e., 12Mbps (Megabytes per second), whereas ADSL can go maximum up to 8Mbps only. ADSL2 also surpasses the basic model in terms of distance it can cover using the same number of copper wires or junction boxes.

ADSL is the foremost or basic model of broadband technology. It enables one to connect to the internet through the subscriber line, i.e., telephone. It is economical and easy to establish internet technology that is common in households as well as offices. It provides an internet connection through the copper wires present in any usual telephone landline.

ADSL2 is the improved version of ADSL broadband technology. It ensures a better and faster internet connection as compared to the former. ADSL2 uses the same technology as ADSL and is also backwards compatible with it. As an upgrade, ADSL2 comes with a higher data speed too.

Comparison Table Between ADSL and ADSL2

Parameters of ComparisonADSLADSL2
ApprovalThe first standard of ADSL got approval in 1998. The first standard of ADSL2 got approval from 2002 to 2007.
VersionIt is the most basic version of ADSL broadband technology. It is the first upgrade to ADSL broadband technology.
ReachIt has a comparatively shorter reach. It can cover a longer distance with the same wires.
Data SpeedThe maximum data speed is 8Mbps. The maximum data speed here is 12Mbps.
Noise Resistance ADSL is not very good at resisting noise. ADSL2 has better noise resistance.
CompatibilityIt is not compatible with ADSL2. It is backwards compatible with ADSL.

What is ADSL?

Nowadays, broadband technology has become a lifesaver, mainly in workplaces and households where heavy data rates are needed. ADSL is one such broadband technology that used the common 2-wire pair fitted in the telephone system to establish an internet connection. As the name suggests, ADSL has an asymmetric bandwidth and bit rate, i.e., they are greater towards downstream than upstream.

Primarily, ADSL serves as internet access that helps to download heavy contents. Although it can be used for surfing too, downloading has always been its main concern. Its maximum data rate is 8Mbps. This data speed is delivered through the spectrum above the used band during voice calls on telephones.

ADSL is installed for not very long distances from the telephone exchange. This is why ADSL2 surpasses the basic ADSL in terms of data rates, as it can cover longer distances, provided that all the other specifications are kept similar. ADSL can only resist a considerable amount of noise, while ADSL does a better job here.

Even after this, ADSL remains the most common choice across households. As ADSL provides a higher bit rate at the customer end, people prefer it over other modems. A better download speed being a priority for home users makes ADSL a suitable option. This can be achieved with the help of full-duplex communication, either by frequency division, echo cancelling or time division.

What is ADSL2?

With time, both scenario and demands of people change. What was the best yesterday might not be the best today! To suffice this, technological advancement is the only solution. Asymmetric Digital Subscriber Line 2 (ADSL2) is the first upgrade made to the ADSL broadband technology.

ADSL2 utilises the same technology as in the ADSL basic model and provides comparatively faster internet access. The downstream data rate is greater than the upstream, and the maximum data speed can go up to 12Mbps. The bandwidth used in ADSL2 is similar to that in ADSL. The improved version is backwards compatible with the basic one, i.e., all the available equipment of ADSL2 can work at ADSL specifications.

However, the upgraded version is more preferred for internet access over longer distances from the exchange. ADSL2 can cover longer distances with the same number of copper wires. Due to this, transmission rates and data speed are improved in ADSL2. Although it has advantages over the former model, its availability is comparatively lower. This is the reason why ADSL is more commonly used in households and offices.

ADSL2 is known for improving Modulation Efficiency, Signal Processing Algorithms, Seamless Rate Adaptation (SRA) etc. SRA allows adjustment in transmission rates based on changing networking requirements. Also, the synchronicity of the transmitted information is preserved in ADSL2.

Main Differences Between ADSL and ADSL2

  1. ADSL is the basic version, whereas ADSL2 is the improved version of ADSL broadband technology.
  2. The first standard of ADSL got approval in 1998, while that of ADSL2 got approval in 2002-2007.
  3. ADSL2 can cover longer distances as compared to ADSL using the same copper wires.
  4. The maximum data speed of ADSL is 8Mbps, which is lesser than that of ADSL2, having a data speed of 12Mbps.
  5. ADSL2 has better noise resisting capacity than ADSL.
  6. ADSL2 is backwards compatible with ADSL, i.e., all equipment of the upgraded version can be used with ADSL specifications, but the reverse is not possible.


The internet has become the life source of humans today. People cannot imagine their lives without it. Everything that we do, say or want to know is possible through internet access. Therefore, a fast and all-rounder internet connection is one of the basic things people wish for nowadays.

Broadband technology is very commonly used for providing internet access. There are various modems introduced for it, and ADSL is one of them. ADSL is the first model that was introduced, followed by its upgrade; ADSL2.

As an improved version, ADSL2 provides faster and better internet connectivity as compared to ADSL. Although ADSL2 has some technical advantages over the basic model, the technology used for both modems is similar.


  1. https://ieeexplore.ieee.org/abstract/document/1630319/
  2. https://digital-library.theiet.org/content/journals/10.1049/ce_20040304
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