ADSL vs SDSL – Difference and Comparison

What is ADSL?

ADSL stands for Asymmetric digital subscriber line. The upload and download speeds vary in this internet broadband connection. The download speeds are always at a higher place than the upload ones. 

It can have high transmission rates and can be used over normal copper telephone wires. This technology is called standardized technology and is used today, giving it a tag of the current technology. 

It is primarily utilized to obtain content from the internet, that is, by downloading them but serving content accessed by others on the internet. Generally, the ADSL systems are installed at a very short distance from telephone exchanges.ADSL provides continuous always available on broadband connections.

A DSL modem is primarily installed where the customer wants it to access an ADSL system. In addition, the installed modem transfers digital data over the local loop of a telephone network. Then a network gets established between the installed modem and the source of the telephone company. 

It operates in a loop of telephone network that connects the telephone company office with the customer’s location. The telephone company uses a DSLAM system to service multiple ADSL users.ADSL networks are full-duplex.ADSL drives a lot of internet connections globally in today’s date.

What is SDSL?

SDSL stands for Symmetric digital subscriber line. As the name suggests, the connection in the case of SDSL is symmetric in working. This means that the upload and download speeds provided by SDSL connections will be equal. DSL transmits digital data through copper wires. 

In the case of SDSL, the bandwidth in the downstream direction from the network provider to a subscriber is equal or symmetric to the bandwidth in the upstream direction from a subscriber to the network.

SDSL is said to be a legacy technology as it was never developed so much. It was founded as a proprietary system, but the standardization procedure never actually took place properly. This brings about certain restrictions in the usage of the SDSL system.

Generally, SDSL is used when data flow in both directions needs to be proper and fast. In situations where a lot of information is getting downloaded and uploaded simultaneously, SDSL plays a vital role. Due to this, SDSL can improve the quality of VoIP calls better than ADSL connections. 

In the case of SDSL, also distance plays a role in maintaining network speeds properly. Yet, due to lack of standardization, this technology is used less than the ADSL technology in today’s world. It is still considered a proprietary technology that does not support a telephone unit over the same line.

Difference Between ADSL and SDSL

  1. ADSL has asymmetric or unequal broadband speeds in uploading and downloading, whereas the speed remains equal in the case of SDSL.
  2. ADSL is a Standardized technology, whereas SDSL is Proprietary in nature.
  3. ADSL technology is used today, while SDSL technology is considered legacy and is used much less than ADSL.
  4. ADSL systems can support a telephone unit on the same line, while it is not possible in the case of SDSL.
  5. The upload speed is comparatively lesser in the case of an ADSL than that of SDSL, yet it does the job.

Comparison Between ADSL and SDSL

Internet speedsUpload and download speeds are differentUpload and download speeds are similar
 Telephone unitCan support a telephonic unit on the same lineDoes not support telephonic unit on the same line
Type of technology StandardizedProprietary 
AdaptationCurrent technology(used today)Legacy technology