Definitions
Asymmetrical Digital Subscriber Line (ADSL) is one of the DSL broadband communication expertise that involves the use of copper telephone lines to send out information that exceeds the capacity of a dial-up modem over the internet (Dhawan 1998, p.5).
Asymmetrical in ADSL refers to the difference that exists between upstream data and downstream data. The upstream data rates are lower compared with the downstream data since the web page requests do not require much bandwidth (Dhawan 1998, p.7).
Digital: ADSL involves the transfer of purely digital information which at the end gets converted to analog signals (Dhawan 1998, p.7).
Subscriber Line: the information is transmitted on copper lines to the customer’s premises (Dhawan 1998, p.7).
ADSL Speed
The speed of the ADSL is affected by the following factors:
- The distance from the local exchange the greater the distance the slower the connection (Carlson, Crilly and Rutledge 2009, P. 37).
- The speed is also affected by the type and the thickness of the wire the thicker the wire the higher the speed (Ginsburg 1999, P. 39).
- The number of joins that are available in the wire and the type of joins can affect the speed. The many they are the slower the speed (Ginsburg 1999, P. 39).
- The distance of the wire to those wires transmitting ISDN, ADSL and other non-voice signals (Carlson, Crilly and Rutledge 2009, P. 38).
- The closeness of the wires to radio transmitters (Ginsburg 1999, P.39).
Various Types of ADSL Standards and Their Speed
The table below shows various ADSL standards available in the market and their corresponding upstream and downstream speed rates (Harte 2004, P. 57).
ADSL Network Components
The ADSL network consists of the following: The ADSL modem (ATU-R) which should be at the subscriber’s place, modem (ATU-C) at the ISP office, Digital Subscriber Line Access Multiplexer (DSLAM), Broadband Access Server (BAS) and lastly Splitter: a filter that is used to split analogue from ADSL data frequencies (Carlson, Crilly and Rutledge 2009, P. 43).
How does ADSL work?
ADSL takes advantage of the idle analogue bandwidth that freely exists in the wires and by using a frequency splitter tool, it divides the conventional voice telephone line into two frequencies where one frequency is used by the telephone and the other by the internet enabling you to use the internet and talk on the phone at the same time (Goralski 2000, P.87).
ADSL Requirements
Following are the requirement needed in order to set up the ADSL services: Phone-line for ADSL, Filter which is used to divide internet from phone signals, ADSL modem, Subscription with an ISP supporting ADSL.
Advantages of Using ADSL
The advantages of using ADSL is their ability to enable you to use internet and telephone signals at the same time using a single telephone line, they contain Constant, high-speed Internet access that’s always online, it is inexpensive, has a high level of security on the data transmitted and lastly it is quick in downloading (Goralski 2000, P.126).
Disadvantages of Using ADSL
The ADSL has its own disadvantages in that its services are affected by the distance from the local hub, it is slow in uploading and the need for a Phone line makes it expensive (Harte 2004, P. 95).
Conclusion
Once you have power your computer on, it connects automatically unless you disconnect it manually using software or hardware (Harte 2004, P. 129).
List of references
Carlson, Crilly and Rutledge, J. (2009) Communication Systems. New York,McGraw-Hill Companies.
Dhawan, C. (1998) Remote Access Networks. 1st edition. New Delhi, Computing Mcgraw-Hill.
Ginsburg, D. (1999) Implementing ADSL. Boston, Addison-Wesley.
Goralski, W. J. (2000) ADSL and DSL Technologies. New Delhi, McGraw-Hill Companies.
Harte, L. J. (2004) Introduction to Transmission Systems, Pots, ISDN, DLC, DSL, OCX Systems and Technologies. New Delhi, Althos.