Advantages and disadvantages of DSL
The Advantages Of DSL:
DSL provides many advantages. Because copper chain wear available means there is no need to install again the infrastructure so that DSL is becoming cheaper. In addition to this direct service DSL is always connected to the ISP and not pay per minute.
Us for the advantages of DSL are:
Simultaneous connections between internet with voice/fax via telephone wire
High access speed and always online
Use of cheap prices especially for housing
Data security preserved
DSL can meet the needs for data transmission at high speed as well as a variety of services but the procurement and maintenance of DSL service is not always easy. The problem that exists between other range limitations, after-sales service and technical support is not good for the customer. Which is also another advantage of DSL technology is the use of existing copper wires where the network had already reached the offices and homes so that the necessary infrastructure development to be not too expensive
Shortage Of DSL:
There are three obstacles confronting the current IE copper telephone cable length to customers, load coils and bridged taps, optical fibers are used for multiple phone lines.
These three barriers are:
Copper cable length from the CO to the customers. Example: If the length of the copper wires over 18.500 feet then service signal to noise ratio is too low and the strengthening of the signal becomes too large to be carried over ADSL speeds reasonable. If the customers are in 18.500 feet were not necessarily guarantee a good service and satisfying because it does not include branches of the copper wires to various customers.
The existence load coils and bridged taps. Local Exchange Carriers (LEC's) using a load coil to provide telephone service in areas that require extra equipment or the installation of the copper loop. Load coil is the equipment induction sound carrier frequency shift up. This was compensation for capacitance cables particularly to reach more than 18.000 feet. Unfortunately, replaceable frequencies to frequencies used for DSL, resulting in interference that cannot be tolerated. So this method makes the line was no match for ADSL. Bridged tap is part of the cable which are not on a line directly from the customer to the co. the Bridged tap makes it easy to LEC to provide copper loops without creating new paths along a distance of customers to the co. If the number is a little bit still allows those lines using DSL. But the echoes and additional noise arising due to the bridged tap can make DSL cannot be hurricane. Some LEC move this equipment but will need quite a long time to clean up the entire line.
The third obstacle is the optical fiber. DSL is a digital service that is made to be carried with the analog channels, namely copper wires. Therefore the signals cannot be sent through the media that use digital transmission such as fiber optics. Usually the optical fiber used for Digital Loop Carrier (DLC) or Subscriber Loop Carrier (SLC). Areas that use optical fibers cannot be served by DSL. To resolve this problem, the phone company test and wear a device called the mini-Remote Access Multiplexers (mini-RAMs) that will facilitate the DSL service for customers behind the DLC and can provide eight channels with DSL service. But it also has limited reach because the copper cable length is not measured from the customer to the co. but from RAM to the customer. In addition, it is not yet known for certain where and when the mini-RAMs should be installed.
DSL technology is the use of existing copper wires where the network had already reached the offices and homes so that the necessary infrastructure development to be not too expensive. But the use of an existing cable it should pay attention to several things related to the data signal. Such as attenuation, crosstalk and noise (noise). Attenuation is weakening the signal caused by the presence of an increasingly far distance that must be taken by a signal, and also because of the increasing frequency of the signal.
Due to the distance and frequency of the farthest distance that still probably is about 5.5 km with a bandwidth of about 1 MHz. Crosstalk will be brought about by the pair telephone wire is used. This disorder can occur due to signals with the same speed of each cable can influence each other, when these disorders are higher compared to the data signal then will arise many errors that slow down the speed of the flow of data. To • avoid the effects of crosstalk can be created for each cable in one direction, so that the signal on each cable is not mutually affect.
