ADSL Technology

ADSL is a modem technology on the access network, which changes the existing infrastructure of the copper pair from the customer's house and the entire communications network, into a broadband network from end to end. ADSL enables, under optimum conditions, the transfer of multimedia, video, audio, high-speed Internet, by means of the existing access network up to a speed of 8 Mbps from the exchange to the subscriber, and up to 768 Kbps from the subscriber to the exchange (hence the name "asymmetric subscriber line").

The basic idea behind the technology is the need to transfer large amounts of information from the exchange to the subscriber's home (downloads of games, movies, etc.) while in the upstream channel (from the subscriber's home to the x exchange) a slower channel is sufficient, enabling communication with the content provider, sending emails or uploading to FTP servers.

ADSL technology uses the existing copper infrastructure deployed all over the country, making the broadband network possible without having to set up a new infrastructure. The technology enables maximum utilization of the typical bandwidth of the copper lines by means of complex data processing and encoding. Instead of using frequencies of 4 kHz, as was done until now, we use a range of frequencies between 0 KHz and 1.1 MHz, where standard ADSL system use 256 frequency channels (for the information moving downstream to from the exchange to the subscriber and for the upstream channel) with a bandwidth of 4 KHz per channel, thus enabling the transfer of much more information.



Technical Characteristics of ADSL

v Asymmetric distribution of the rate – up to 8 Mbps on the downstream channel and up to 768 on the u[stream channel.

v The range of frequencies is higher than the basic telephone frequency and up to a 1 MHz frequency.

v It is enabled on a regular analog telephone line or on an ISDN line.

v All the features of the line are maintained (such as conference call, call waiting, etc.).

v It is possible to surf the Internet and talk on the same line simultaneously (the use of filters does away with the need for a separate line for the Internet).