ADSL

Asymmetric Digital Subscriber Line (ADSL) is a form of DSL technology. ADSL broadband is fast internet access over conventional telephone lines while allowing a simultaneous voice communication. The telephone line is actually quite capable of handling frequencies of several million Herz. In the system of analog signals handled by the POTS – Plain Old Telephone Service - the conventional telephone system, there would have been a chaos of interference and noise in a closely packed bundle of wires carrying voice communication. The POTS avoids this chaos by limiting the range of frequencies handled by its equipments and lines. But the lines by themselves are still capable of handling the large bandwidth.

ADSL technology makes use of this idle capacity of the telephone lines to provide a fairly economical system of internet connection. Due to the use of high frequency signals, ADSL technology system is limited to operation within a radius of a maximum of 5 km from the telephone company’s local office. At the telephone company’s office, the ADSL high frequency signal is stripped off and routed to the conventional internet network while any voice frequency signal is switched into conventional telephone network.

As the name implies, the ADSL system is asymmetric – it permits greater speed of data flow to the user (download) as compared to the other direction (upload). This system is immensely suited to the requirements of a home user who is more interested in downloading information, music, videos, etc. rather than sending massive data out. This asymmetric operation is accomplished by the use of two frequency bands; one for upstream or uploading and the other for downstream or downloading. Voice communication is restricted to frequencies up to 4 kHz, upstream from 25 to 138 kHz and downstream from 138 kHz to 1100 kHz. ADSL speed for downloading can be 1.5 to 8 Mbps while the ADSL speed for uploading could be from 16 to 832 kbps.

Since ADSL performance deteriorates as the user location is at a far distance from the local telephone company’s office, it is advisable that in doubtful cases ADSL speed check must be done after installation. This facility of conducting ADSL speed test is easily available at no extra cost. You may also find out about the ADSL broadband deals and find out more about ADSL web hosting and VGA ADSL from the service representatives.

Installation of ADSL system at the user ends requires ADSL modems (or ADSL routers / ADSL broadband routers) which connect user computers to the telephone line and ADSL filters (also called ADSL splitters) which separate voice frequency signals from the high frequency ADSL signals. It’s best you get your ADSL modem from your service provider.

ADSL is a fairly popular system and there are numerous ADSL broadband ISP (Internet Service Providers) such as Optus ADSL available.